6SL3053-0AA00-3AA1 - SIEMENS

siemens.com/drives

Version

6.5

SINAMICS Drives

Edition

July

2017

SINAMICS - Low Voltage

Engineering Manual

SINAMICS G130, G150, S120 Chassis,

S120 Cabinet Modules, S150

Supplement to Catalogs D 11 and D 21.3

Literary reference

The following title by Jens Weidauer, Richard Messer

Electrical Drives

Principles • Planning • Applications • Solutions

offers a wide-ranging, clear and comprehensible overview of modern drive systems.

The book covers all aspects of modern electrical drive systems from the viewpoint of the user. On the one hand, it is

aimed at practicians who want to understand, design, use and maintain electrical

drives. On the other, it will be a useful reference document for skilled workers,

technicians, engineers and students who wish to gain a broad general

understanding of electrical drive technology. The author explains the

fundamentals of electrical drives and their design, and goes on to describe

different applications as well as complex automation solutions. He presents the

entire spectrum of drive solutions with the relevant core applications in each

case. He gives special attention to the practice of combining multiple drives into

drive systems and to the integration of drives into automated systems.

In simple, plain language and illustrated by numerous graphics, complex

relationships are explained in a clear and coherent manner. The author

consciously avoids the use of complicated mathematical formulae, concentrating

instead on providing plain, comprehensible explanations of operating principles

and relationships. The book is designed to help readers to understand electrical

drive systems in their entirety and to solve the drive-related problems they may

encounter in their daily working lives.

Contents

1Overview

2Mechanical principles

3Electrical principles

4Fixed-speed and variable-speed drives with direct current motor

5Fixed-speed and variable-speed drives with asynchronous motor

6Servo drives

7 Stepper drives

8Electrical drives at a glance

9Fieldbuses for electrical drives

10 Process control with electrical drives

11 Motion control

12 EMC and electrical drives

13 Planning electrical drives

14 Troubleshooting on electrical drives

Print ISBN: 978-3-89578-434-7

ePDF ISBN: 978-3-89578-923-6

1st Edition 2014

Published by: Siemens Aktiengesellschaft, Berlin and Munich

Publishing house: Publicis Publishing, Erlangen

www.publicis-books.de

SINAMICS Engineering Manual – July 2017

Ó Siemens AG 3/554

sForeword

List of Contents

SINAMICS Low Voltage

Engineering Manual

Fundamental Principles and System Description

Version 6.5 – July 2017

Supplement to Catalogs D 11 and D 21.3

EMC Installation Guideline

General Engineering Information for SINAMICS

Converter Chassis Units

SINAMICS G130

Converter Cabinet Units

SINAMICS G150

General Information about Built-in and Cabinet Units

SINAMICS S120

General Information about Modular Cabinet Units

SINAMICS S120 Cabinet Modules

Converter Cabinet Units

SINAMICS S150

Disclaimer

We have checked that the contents of this document

correspond to the hardware and software described.

However, as deviations cannot be totally excluded, we are

unable to guarantee complete consistency. The information

given in this publication is reviewed at regular intervals and

any corrections that might be necessary are made in the

subsequent editions.

Subject to change without prior notice.

ã Siemens AG 2017

Description of Options for Cabinet Units

SINAMICS G150, S120 Cabinet Modules, S150

General Information about Drive Dimensioning

Motors

Foreword

Engineering Information

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To all SINAMICS customers!

This engineering manual is supplementary to the SINAMICS Catalogs D 11 and D 21.3 and is designed to provide

additional support to users of SINAMICS converters. It focuses on drives with units in Chassis and Cabinet format in

the output power range ≥ 75 KW and operating in vector control mode (drive objects of vector type).

All information in this engineering manual refers to device variants equipped with the following hardware and

software:

· Power unit with Control Interface Module CIM (article number ending in 3, e.g. 6SL3310-1GE38-4AA3)

· CU320-2 Control Unit

· Firmware version 4.3 or higher

The engineering manual contains a general analysis of the fundamental principles of variable-speed drives as well as

detailed system descriptions and specific information about the following units in the SINAMICS equipment range:

· Converter Chassis Units SINAMICS G130 (Catalog D 11)

· Converter Cabinet Units SINAMICS G150 (Catalog D 11)

· Modular Chassis Units SINAMICS S120 (Catalogs D 21.3

and D 21.4 / "SINAMICS S120 Drive System")

· Modular Cabinet Units SINAMICS S120 Cabinet Modules (Catalog D 21.3)

· Converter Cabinet Units SINAMICS S150 (Catalog D 21.3)

This engineering manual is divided into different chapters.

The first chapter "Fundamental Principles and System Description" focuses on the physical fundamentals of electrical

variable-speed three-phase AC drives and provides general system descriptions of products in the SINAMICS range.

The second chapter “EMC Installation Guideline” gives an introduction to the subject of Electromagnetic Compatibility

(EMC), and provides all information required to engineer and install drives with the aforementioned SINAMICS

devices in an EMC-compliant manner.

The following chapters, which describe how to engineer SINAMICS G130, G150, S120 Built-in units, S120 Cabinet

Modules and S150, focus on subjects relating to specific units in more detail than the general system descriptions.

This engineering manual can and should only be viewed as a supplement to catalogs D 11, D 21.3 and D 21.4 /

"SINAMICS S120 Drive System". The document does not therefore contain any ordering data. The manual is

available only in electronic form in German or English.

The information of this manual is aimed at technically qualified and trained personnel. The configuring engineer is

responsible for assessing whether the information provided is sufficiently comprehensive for the application in

question and, therefore, assumes overall responsibility for the whole drive or the whole system.

The information provided in this engineering manual contains descriptions or characteristics of performance which in

case of actual use do not always apply as described, or which may change as a result of further development of the

products.

The desired performance characteristics are firmly binding only if expressly agreed upon in the contract.

Availability and technical specifications are subject to change without prior notice.

EMC warning information

The SINAMICS converter systems G130, G150, S120 Chassis units, S120 Cabinet Modules and S150 are not

designed to be connected to public networks (first environment). RFI suppression of these converter systems is

designed for industrial networks (second environment) in accordance with the EMC product standard EN 61800-3 for

variable-speed drives. If the converter systems are connected to public networks (first environment) electromagnetic

interference can occur. With additional measures (e.g. EMC-filters) the converter systems can also be connected to

public networks

Foreword

Engineering Information

SINAMICS Engineering Manual – July 2017

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Overview of the most significant additions and modifications as compared

to version 6.4 of this Engineering Manual

1.1.3.5 Influence of the pulse frequency on the motor noise

à Additional information has been added to this section. It now includes an explanation of the

boundary conditions under which the pulse frequency on drives with square-law load characteristic

can be increased above the factory setting without the need to apply a current derating.

1.3.4 Three-winding transformers

à This section which defines the relevant boundary conditions for 12-pulse drive solutions, as well as

sections 1.15.3, 1.15.4 and 5.9.2 which specify the appropriate boundary conditions for the 12-pulse

operation of S120 Basic Line Modules, S120 Smart Line Modules and parallel connections of G150

converters, now contain additional information. In addition to the requirements of the three-winding

transformer, the cabling and the SINAMICS Infeeds, further conditions to be fulfilled by the supply

system are also defined (permissible harmonics).

1.4.6 Standards and permissible harmonics

à This section has been updated because standard IEEE 519 – 1992 (Recommended Practice and

Requirements for Harmonic Control in Electrical Power Systems) has been superseded by the current

version of IEEE 519 – 2014 which has resulted in a number of minor changes.

1.8.2.1 Connection of Motor Modules to the DC busbar, fuse protection and precharging

à An explanation as to how the precharging contactor and the contactor are controlled by the Motor

Module has been added to this section.

1.10.2.2 Supplementary conditions which apply when dv/dt filters are used

à A more precise description of the restrictions applicable to the dv/dt filter compact plus VPL at low

output frequencies has been added to this section.

1.10.3.2 Supplementary conditions which apply when sine-wave filters are used

à Additional information has been added to this section. The relevant boundary conditions which

must be taken into account when third-party filters are used in order to achieve a stable control-

behaviour in operation have been specified at the end of the section.

1.12 Power cycling capability of IGBT modules and inverter power units

à More precise information about the current derating curves for operation at low output frequencies

of < 10 Hz has been added to this section.

1.13 Load duty cycles

à The derating characteristics 1 to 3 for calculating the current derating factor kIGBT for periodic load

duty cycles have been updated in this section.

1.16 SINAMICS S120 liquid-cooled and water-cooled units

à This section has been revised because the coolant definitions, inhibitors and anti-freezes for liquid-

cooled units have been updated.

A description of the new water-cooled units equipped with a copper-nickel cooling circuit has also

been added.

7.3 Liquid-cooled SINAMICS S120 Cabinet Modules

à This section has been revised by the addition of the following new information/changes:

- The cooling water definition, inhibitors and anti-freezes have been updated

- The new Active Line Connection Modules have been added

- The new Motor Modules have been added

- The new Auxiliary Power Supply Modules have been added

- The description of the Heat Exchanger Modules has been updated

─The EU Directives have been updated

à The EU Directives cited in this document have been updated.

─Correction of errors

à Spelling and formatting errors have been corrected.

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List of Contents

1 Fundamental Principles and System Description .......................................................................... 16

1.1 Operating principle of SINAMICS converters .............................................................................................. 16

1.1.1 General operating principle ............................................................................................................ 16

1.1.2 Pulse modulation method ............................................................................................................... 16

1.1.2.1 Generation of a variable voltage by pulse-width modulation ............................................................. 17

1.1.2.2 Maximum attainable output voltage with space vector modulation SVM ........................................... 18

1.1.2.3 Maximum attainable output voltage with pulse-edge modulation PEM .............................................. 19

1.1.3 The pulse frequency and its influence on key system properties ...................................................... 21

1.1.3.1 Factory settings and ranges of pulse frequency settings .................................................................. 21

1.1.3.2 Interrelationships between current controller clock cycle, pulse frequency and output frequency ....... 21

1.1.3.3 Influence of the pulse frequency on the inverter output current ........................................................ 24

1.1.3.4 Influence of the pulse frequency on losses and efficiency of inverter and motor................................ 24

1.1.3.5 Influence of the pulse frequency on the motor noise ........................................................................ 24

1.1.3.6 Correlation between pulse frequency and motor-side options .......................................................... 27

1.1.4 Open-loop and closed-loop control modes ...................................................................................... 28

1.1.4.1 General information about speed adjustment .................................................................................. 28

1.1.4.2 V/f control modes ........................................................................................................................... 28

1.1.4.3 Field-oriented control modes .......................................................................................................... 30

1.1.4.4 A comparison of the key features of open-loop and closed-loop control modes ................................ 32

1.1.4.5 Load balance on mechanically coupled drives................................................................................. 32

1.1.5 Power ratings of SINAMICS converters and inverters / Definition of the output power ....................... 34

1.2 Supply systems and supply system types .................................................................................................. 36

1.2.1 General ......................................................................................................................................... 36

1.2.2 Connection of converters to the supply system and protection of converters .................................... 38

1.2.3 Short Circuit Current Rating (SCCR according to UL) ...................................................................... 39

1.2.4 Maximum short-circuit currents (SCCR according to IEC) and minimum short-circuit currents ..................... 40

1.2.5 Connection of converters to grounded systems (TN or TT) .............................................................. 45

1.2.6 Connection of converters to non-grounded systems (IT) .................................................................. 46

1.2.7 Connection of converters to supply systems with different short-circuit powers ................................. 50

1.2.8 Supply voltage variations and supply voltage dips ........................................................................... 52

1.2.9 Behaviour of SINAMICS converters during supply voltage variations and dips ................................. 53

1.2.10 Permissible harmonics on the supply voltage .................................................................................. 60

1.2.11 Summary of permissible supply system conditions for SINAMICS converters ................................... 61

1.2.12 Line-side contactors and circuit breakers ........................................................................................ 62

1.3 Transformers ............................................................................................................................................... 67

1.3.1 Unit transformers ........................................................................................................................... 67

1.3.1.1 General information about calculating the required apparent power of a unit transformer .................. 67

1.3.1.2 Method of calculating the required apparent power S of a unit transformer ....................................... 69

1.3.2 Transformer types .......................................................................................................................... 70

1.3.3 Features of standard transformers and converter transformers ........................................................ 71

1.3.4 Three-winding transformers ............................................................................................................ 72

1.4 Harmonic effects on the supply system ...................................................................................................... 74

1.4.1 General ......................................................................................................................................... 74

1.4.2 Harmonic currents of 6-pulse rectifier circuits .................................................................................. 76

1.4.2.1 SINAMICS G130, G150, S120 Basic Infeed and S120 Smart Infeed in motor operation ................... 76

1.4.2.2 SINAMICS S120 Smart Infeed in regenerative operation ................................................................. 78

1.4.3 Harmonic currents of 6-pulse rectifier circuits with Line Harmonics Filter .......................................... 79

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1.4.4 Harmonic currents of 12-pulse rectifier circuits .................................................................................81

1.4.5 Harmonic currents and harmonic voltages of Active Infeeds (AFE technology)..................................82

1.4.6 Standards and permissible harmonics .............................................................................................84

1.5 Line-side reactors and filters .......................................................................................................................88

1.5.1 Line reactors (line commutating reactors) ........................................................................................88

1.5.2 Line Harmonics Filters (LHF and LHF compact)...............................................................................89

1.5.2.1 Operating principle of Line Harmonics Filters (LHF and LHF compact) .............................................89

1.5.2.2 Line Harmonics Filter (LHF) with separate housing (6SL3000-0J_ _ _-_AA0) ...................................90

1.5.2.3 Line Harmonics Filter compact (LHF compact) as Option L01 for SINAMICS G150 ...........................92

1.5.3 Line filters (radio frequency interference (RFI) suppression filter or EMC filter) .................................94

1.5.3.1 General information and standards..................................................................................................94

1.5.3.2 Line filters for the "first" environment (residential) and "second" environment (industrial) ..........................97

1.5.3.3 Operating principle of line filters ......................................................................................................97

1.5.3.4 Magnitude of leakage or interference currents .................................................................................98

1.5.3.5 EMC-compliant installation ..............................................................................................................99

1.6 SINAMICS Infeeds and their properties ...................................................................................................... 102

1.6.1 Basic Infeed ................................................................................................................................. 102

1.6.2 Smart Infeed ................................................................................................................................ 104

1.6.3 Active Infeed ................................................................................................................................ 107

1.6.4 Comparison of the properties of the different SINAMICS Infeeds .................................................... 112

1.6.5 – – –........................................................................................................................................... 114

1.6.6 Redundant line supply concepts .................................................................................................... 114

1.6.7 Permissible total cable length for S120 Infeed Modules feeding multi-motor drives ......................... 119

1.7 SINAMICS braking units (Braking Modules and braking resistors) ........................................................... 120

1.8 SINAMICS Inverters or Motor Modules....................................................................................................... 121

1.8.1 Operating principle and properties ................................................................................................. 121

1.8.2 Drive configurations with multiple Motor Modules connected to a common DC busbar .................... 122

1.8.2.1 Connection of Motor Modules to the DC busbar, fuse protection and precharging ........................... 122

1.8.2.2 Arrangement of Motor Modules along the DC busbar ..................................................................... 124

1.8.2.3 Permissible dimensions and topologies of the DC busbar .............................................................. 127

1.8.2.4 Short-circuit currents on the DC busbar ......................................................................................... 129

1.8.2.5 Maximum power rating of drive configurations at a common DC busbar ......................................... 131

1.9 Effects of using fast-switching power components (IGBTs) ..................................................................... 133

1.9.1 Increased current load on the inverter output as a result of long motor cables ................................. 133

1.9.2 Special issues relating to motor-side contactors and circuit breakers .............................................. 135

1.9.3 Increased voltage stress on the motor winding as a result of long motor cables .............................. 136

1.9.4 Bearing currents caused by steep voltage edges on the motor ....................................................... 141

1.9.4.1 Measures for reducing bearing currents......................................................................................... 142

1.9.4.1.1 EMC-compliant installation for optimized equipotential bonding in the drive system ........................ 143

1.9.4.1.2 Insulated bearing at the non-drive end (NDE) of the motor ............................................................. 147

1.9.4.1.3 Other measures............................................................................................................................ 147

1.9.4.2 Summary of bearing current types and counter-measures .............................................................. 148

1.10 Motor-side reactors and filters ................................................................................................................. 150

1.10.1 Motor reactors .............................................................................................................................. 150

1.10.1.1 Reduction of the voltage rate-of-rise dv/dt at the motor terminals.................................................... 150

1.10.1.2 Reduction of additional current peaks when long motor cables are used......................................... 150

1.10.1.3 Permissible motor cable lengths with motor reactor(s) for single- and multi-motor drives ................. 151

1.10.1.4 Supplementary conditions which apply when motor reactors are used ............................................ 154

1.10.2 dv/dt filters plus VPL and dv/dt filters compact plus VPL ................................................................ 155

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1.10.2.1 Design and operating principle ..................................................................................................... 155

1.10.2.2 Supplementary conditions which apply when dv/dt-filters are used ................................................ 156

1.10.3 Sine-wave filters .......................................................................................................................... 158

1.10.3.1 Design and operating principle ..................................................................................................... 158

1.10.3.2 Supplementary conditions which apply when sine-wave filters are used ......................................... 159

1.10.4 Comparison of the properties of the motor-side reactors and filters ................................................ 161

1.11 – – – ........................................................................................................................................................ 163

1.12 Power cycling capability of IGBT modules and inverter power units ..................................................... 163

1.12.1 General ....................................................................................................................................... 163

1.12.2 IGBT module with cyclically alternating current load ...................................................................... 163

1.12.3 Dimensioning of the power units for operation at low output frequencies ........................................ 164

1.13 Load duty cycles ...................................................................................................................................... 168

1.13.1 General ....................................................................................................................................... 168

1.13.2 Standard load duty cycles ............................................................................................................ 168

1.13.3 Free load duty cycles ................................................................................................................... 169

1.13.4 Thermal monitoring of the power unit ............................................................................................ 183

1.13.5 Operation of converters at increased pulse frequency ................................................................... 183

1.14 Efficiency of SINAMICS converters at full load and at partial load ......................................................... 187

1.14.1 Converter efficiency at full load ..................................................................................................... 187

1.14.2 Converter efficiency at partial load ................................................................................................ 188

1.14.2.1 – – – .......................................................................................................................................... 188

1.14.2.2 Partial load efficiency of S120 Basic Line Modules ........................................................................ 188

1.14.2.3 Partial load efficiency of S120 Smart Line Modules ....................................................................... 189

1.14.2.4 Partial load efficiency of S120 Active Line Modules + Active Interface Modules .............................. 189

1.14.2.5 Partial load efficiency of S120 Motor Modules ............................................................................... 190

1.14.2.6 Partial load efficiency of G130 / G150 converters .......................................................................... 191

1.14.2.7 Partial load efficiency of S150 converters ...................................................................................... 193

1.15 Parallel connections of converters .......................................................................................................... 196

1.15.1 General ....................................................................................................................................... 196

1.15.2 Parallel connections of SINAMICS converters ............................................................................... 196

1.15.3 Parallel connection of S120 Basic Line Modules ........................................................................... 198

1.15.4 Parallel connection of S120 Smart Line Modules ........................................................................... 201

1.15.5 Parallel connection of S120 Active Line Modules .......................................................................... 204

1.15.6 Parallel connection of S120 Motor Modules .................................................................................. 206

1.15.7 Admissible and inadmissible winding systems for parallel connections of converters ...................... 208

1.16 Liquid-cooled and water-cooled SINAMICS S120 units ........................................................................... 211

1.16.1 General ....................................................................................................................................... 211

1.16.2 Liquid-cooled SINAMICS S120 units ......................................................................................... 212

1.16.2.1 Design of the liquid-cooled units in Chassis format ........................................................................ 212

1.16.2.2 Cooling circuit and coolant requirements....................................................................................... 213

1.16.2.3 Example of a closed cooling circuit for liquid-cooled SINAMICS S120 units.................................... 216

1.16.2.4 Example of coolant temperature control for condensation prevention ............................................. 217

1.16.2.5 Information about cooling circuit configuration ............................................................................... 220

1.16.2.6 Information about cabinet design .................................................................................................. 229

1.16.3 Water-cooled SINAMICS S120 units for a common cooling circuit .......................................... 233

1.16.3.1 Design of the water-cooled units in Chassis format ....................................................................... 233

1.16.3.2 Cooling circuit and coolant requirements....................................................................................... 234

1.16.3.3 Example of a closed cooling circuit for water-cooled SINAMICS S120 units ................................... 237

1.16.3.4 Example of a half-open cooling circuit for water-cooled SINAMICS S120 units ............................... 237

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1.16.3.5 Example of coolant temperature control for condensation prevention ............................................. 238

1.16.3.6 Information about cooling circuit configuration ............................................................................... 241

1.16.3.7 Information about cabinet design................................................................................................... 248

2 EMC Installation Guideline ............................................................................................................249

2.1 Introduction ................................................................................................................................................ 249

2.1.1 General ........................................................................................................................................ 249

2.1.2 EU Directives ............................................................................................................................... 249

2.1.3 CE marking .................................................................................................................................. 249

2.1.4 EMC Directive .............................................................................................................................. 250

2.1.5 EMC product standard EN 61800-3 ............................................................................................... 250

2.2 Fundamental principles of EMC ................................................................................................................. 252

2.2.1 Definition of EMC ......................................................................................................................... 252

2.2.2 Interference emissions and interference immunity.......................................................................... 253

2.3 The frequency converter and its EMC ........................................................................................................ 253

2.3.1 The frequency converter as a source of interference ...................................................................... 253

2.3.2 The frequency converter as a high-frequency source of interference .............................................. 254

2.3.3 The frequency converter as a low-frequency source of interference ................................................ 258

2.3.4 The frequency converter as potentially susceptible equipment ....................................................... 259

2.3.4.1 Methods of influence..................................................................................................................... 259

2.3.4.1.1 Conductive coupling ..................................................................................................................... 259

2.3.4.1.2 Capacitive coupling ...................................................................................................................... 260

2.3.4.1.3 Inductive coupling ......................................................................................................................... 261

2.3.4.1.4 Electromagnetic coupling (radiative coupling) ................................................................................ 262

2.4 EMC-compliant installation ........................................................................................................................ 262

2.4.1 Zone concept within the converter cabinet ..................................................................................... 263

2.4.2 Converter cabinet structure ........................................................................................................... 264

2.4.3 Cables inside the converter cabinet ............................................................................................... 264

2.4.4 Cables outside the converter cabinet ............................................................................................. 265

2.4.5 Cable shields................................................................................................................................ 265

2.4.6 Equipotential bonding in the converter cabinet, in the drive system, and in the plant ....................... 265

2.4.7 Examples for installation ............................................................................................................... 267

2.4.7.1 EMC-compliant installation of a SINAMICS G150 converter cabinet unit ......................................... 267

2.4.7.2 EMC-compliant construction/installation of a cabinet with a SINAMICS G130 Chassis unit .............. 268

2.4.7.3 EMC-compliant cable routing on the plant side on cable racks and in cable ducts ........................... 269

3 General Engineering Information for SINAMICS...........................................................................271

3.1 Overview of documentation ....................................................................................................................... 271

3.2 Safety-integrated / Drive-integrated safety functions ................................................................................ 276

3.2.1 Safety Integrated Basic Functions Safe Torque Off (STO) and Safe Stop 1 (SS1)........................... 276

3.3 Precharging intervals of the DC link .......................................................................................................... 280

3.3.1 SINAMICS Booksize units ............................................................................................................. 280

3.3.2 SINAMICS Chassis units .............................................................................................................. 280

3.4 Operator Panels .......................................................................................................................................... 280

3.4.1 Basic Operator Panel (BOP20) ..................................................................................................... 280

3.4.2 Advanced Operator Panel (AOP30)............................................................................................... 280

3.5 CompactFlash Cards for CU320-2 Control Units ....................................................................................... 282

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3.6 Cabinet design and air conditioning.......................................................................................................... 283

3.6.1 Directives and standards .............................................................................................................. 283

3.6.2 Physical fundamental principles .................................................................................................... 285

3.6.3 Cooling air requirements and air opening cross-sections in the cabinet .......................................... 287

3.6.4 Required ventilation clearances .................................................................................................... 289

3.6.5 Required partitioning .................................................................................................................... 291

3.6.6 Prevention of condensation in equipment cooled by air conditioners and climate control systems ... 292

3.7 Installation fixture for power blocks and power units ............................................................................... 293

3.8 Replacement of SIMOVERT P and SIMOVERT A converter ranges by SINAMICS .................................... 294

3.8.1 General ....................................................................................................................................... 294

3.8.2 Replacement of converters in SIMOVERT P 6SE35/36 and 6SC36/37 ranges by SINAMICS ......... 294

3.8.3 Replacement of converters in SIMOVERT A range by SINAMICS ................................................. 296

4 Converter Chassis Units SINAMICS G130 .................................................................................... 298

4.1 General information ................................................................................................................................... 298

4.2 Rated data of converters for drives with low demands on control performance...................................... 301

4.3 Connection diagram of the Power Module ................................................................................................ 307

4.4 Incorporating different loads into the 24 V supply .................................................................................... 308

4.5 Factory settings (defaults) of customer interface on SINAMICS G130 ..................................................... 309

4.6 Cable cross-sections and connections on SINAMICS G130 Chassis Units .............................................. 314

4.7 Precharging of the DC link and precharging currents .............................................................................. 314

4.8 Line-side components ............................................................................................................................... 316

4.8.1 Line fuses .................................................................................................................................... 316

4.8.2 Line reactors ................................................................................................................................ 316

4.8.3 Line Harmonics Filters ................................................................................................................. 317

4.8.4 Line filters .................................................................................................................................... 317

4.9 Components at the DC link ........................................................................................................................ 318

4.9.1 Braking units ................................................................................................................................ 318

4.10 Load-side components and cables .......................................................................................................... 322

4.10.1 Motor reactors ............................................................................................................................. 322

4.10.2 dv/dt filters plus VPL .................................................................................................................... 322

4.10.3 Sine-wave filters .......................................................................................................................... 322

4.10.4 Maximum connectable motor cable lengths................................................................................... 322

5 Converter Cabinet Units SINAMICS G150 ..................................................................................... 324

5.1 General information ................................................................................................................................... 324

5.2 Rated data of converters for drives with low demands on control performance...................................... 324

5.3 Factory settings (defaults) of customer interface on SINAMICS G150 with TM31 .................................... 331

5.4 Cable cross-sections and connections on SINAMICS G150 Cabinet Units .............................................. 333

5.4.1 Recommended and max. possible cable cross-sections for line and motor connections ................. 333

5.4.2 Required cable cross-sections for line and motor connections ....................................................... 335

5.4.3 Grounding and PE conductor cross-section .................................................................................. 336

5.5 Precharging of the DC link and precharging currents .............................................................................. 337

5.6 Line-side components ............................................................................................................................... 339

5.6.1 Line fuses .................................................................................................................................... 339

5.6.2 Line reactors ................................................................................................................................ 339

5.6.3 Line Harmonics Filters ................................................................................................................. 340

5.6.4 Line filters .................................................................................................................................... 340

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5.7 Components at the DC link......................................................................................................................... 341

5.7.1 Braking units ................................................................................................................................ 341

5.8 Load-side components and cables ............................................................................................................ 345

5.8.1 Motor reactors .............................................................................................................................. 345

5.8.2 dv/dt filters plus VPL and dv/dt filters compact plus VPL ................................................................ 345

5.8.3 Sine-wave filters ........................................................................................................................... 345

5.8.4 Maximum connectable motor cable lengths ................................................................................... 346

5.9 SINAMICS G150 parallel converters (SINAMICS G150 power extension) .................................................. 346

5.9.1 6-pulse operation of SINAMICS G150 parallel converters .............................................................. 349

5.9.2 12-pulse operation of SINAMICS G150 parallel converters ............................................................ 350

5.9.3 Operation at motors with electrically isolated and with common winding systems ............................ 352

5.9.4 Special features to note when precharging SINAMICS G150 parallel converters ............................. 354

5.9.5 Overview of SINAMICS G150 parallel converters .......................................................................... 357

6 General Information about Built-in and Cabinet Units SINAMICS S120 ......................................358

6.1 General ....................................................................................................................................................... 358

6.1.1 Assignment table .......................................................................................................................... 358

6.2 Control properties ...................................................................................................................................... 358

6.2.1 Performance features of the CU320-2 Control Unit ........................................................................ 358

6.2.2 Control properties / definitions ....................................................................................................... 360

6.2.3 Control properties of the CU320-2 Control Unit .............................................................................. 361

6.2.4 Determination of the required control performance of the CU320-2 Control Unit .............................. 368

6.3 Rated data, permissible output currents, maximum output frequencies .................................................. 371

6.3.1 Permissible output currents and maximum output frequencies ....................................................... 371

6.3.2 Ambient temperatures > 40°C and installation altitudes > 2000 m .................................................. 372

6.4 DRIVE-CLiQ ................................................................................................................................................ 374

6.4.1 Basic information .......................................................................................................................... 374

6.4.2 Determination of component cabeling............................................................................................ 375

6.4.3 DRIVE-CLiQ cables supplied with the units ................................................................................... 376

6.4.4 Cable installation .......................................................................................................................... 377

6.5 Precharging of the DC link and precharging currents ............................................................................... 380

6.5.1 Basic Infeed ................................................................................................................................. 380

6.5.2 Smart Infeed ................................................................................................................................ 382

6.5.3 Active Infeed ................................................................................................................................ 384

6.6 Checking the maximum DC link capacitance ............................................................................................. 386

6.6.1 Basic information .......................................................................................................................... 386

6.6.2 Capacitance values ...................................................................................................................... 387

6.7 Connection of Motor Modules to a common DC busbar ............................................................................ 391

6.7.1 Direct connection to the DC busbar ............................................................................................... 391

6.8 Braking Modules / External braking resistors ............................................................................................ 392

6.8.1 Braking Modules for power units in Chassis format ........................................................................ 392

6.8.2 Braking resistors for power units in Chassis format ........................................................................ 395

6.8.3 SINAMICS S120 Motor Modules as 3-phase Braking Modules ....................................................... 396

6.9 Maximum connectable motor cable lengths .............................................................................................. 401

6.9.1 Booksize units .............................................................................................................................. 401

6.9.2 Chassis units ................................................................................................................................ 402

6.10 Checking the total cable length for multi-motor drives ........................................................................... 403

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6.11 Parallel connections of Motor Modules ................................................................................................... 404

6.11.1 General ....................................................................................................................................... 404

6.11.2 Minimum motor cable lengths for motors with common winding system ......................................... 404

7 General Information about Modular Cabinet Units SINAMICS S120 Cabinet Modules ............... 405

7.1 General ....................................................................................................................................... 405

7.2 Air-cooled SINAMICS S120 Cabinet Modules ............................................................................................ 406

7.2.1 General configuring process .................................................................................................................. 406

7.2.2 Dimensioning information for air-cooled S120 Cabinet Modules........................................................... 407

7.2.2.1 Derating data of air-cooled S120 Cabinet Modules ........................................................................ 407

7.2.2.1.1 Derating data for S120 Cabinet Modules with power units in Chassis format .................................. 407

7.2.2.1.2 Derating data for S120 Cabinet Modules with power units in Booksize format ................................ 408

7.2.2.2 Degrees of protection of air-cooled S120 Cabinet Modules ............................................................ 409

7.2.2.3 Required DC busbar cross-sections and maximum short-circuit currents ....................................... 409

7.2.2.4 Required cable cross-sections for line and motor connections ....................................................... 410

7.2.2.5 Cooling air requirements of air-cooled S120 Cabinet Modules ....................................................... 412

7.2.2.6 Auxiliary power requirements ....................................................................................................... 413

7.2.2.7 Line reactors ................................................................................................................................ 421

7.2.2.8 Line Harmonics Filter ................................................................................................................... 422

7.2.2.9 Line filters .................................................................................................................................... 422

7.2.2.10 Parallel configuration.................................................................................................................... 423

7.2.2.11 Weights of S120 Cabinet Modules ................................................................................................ 424

7.2.3 Information about equipment handling of air-cooled units .................................................................... 427

7.2.3.1 Customer terminal block -X55 ...................................................................................................... 427

7.2.3.2 Customer terminal blocks -X55.1 and -X55.2 ................................................................................ 429

7.2.3.3 Auxiliary voltage supply system .................................................................................................... 430

7.2.3.4 DRIVE-CLiQ wiring ...................................................................................................................... 432

7.2.3.5 Erection of cabinets ..................................................................................................................... 433

7.2.3.6 Examples of Cabinet Modules arrangements ................................................................................ 433

7.2.3.7 Door opening angle ...................................................................................................................... 434

7.2.4 Line Connection Modules ....................................................................................................................... 435

7.2.4.1 Design ......................................................................................................................................... 435

7.2.4.2 Planning recommendations, special features ................................................................................ 436

7.2.4.3 Assignment to the rectifiers / Line Modules ................................................................................... 436

7.2.4.4 Parallel connections ..................................................................................................................... 437

7.2.4.5 DC busbar ................................................................................................................................... 438

7.2.4.6 Circuit breakers ........................................................................................................................... 438

7.2.4.7 Short-circuit strength .................................................................................................................... 440

7.2.5 Basic Line Modules ................................................................................................................................. 441

7.2.5.1 Design ......................................................................................................................................... 441

7.2.5.2 DC link fuses ............................................................................................................................... 442

7.2.5.3 Parallel connections of Basic Line Modules................................................................................... 442

7.2.6 Smart Line Modules ................................................................................................................................ 443

7.2.6.1 Design ......................................................................................................................................... 443

7.2.6.2 DC link fuses ............................................................................................................................... 444

7.2.6.3 Parallel connections of Smart Line Modules .................................................................................. 444

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7.2.7 Active Line Modules + Active Interface Modules .................................................................................... 445

7.2.7.1 Design ......................................................................................................................................... 445

7.2.7.2 DC Link fuses ............................................................................................................................... 447

7.2.7.3 Parallel connections of Active Line Modules + Active Interface Modules ......................................... 447

7.2.8 Motor Modules ......................................................................................................................................... 449

7.2.8.1 Design ......................................................................................................................................... 449

7.2.8.2 DC link fuses ................................................................................................................................ 449

7.2.8.3 Parallel connections of Motor Modules .......................................................................................... 450

7.2.8.3.1 General ........................................................................................................................................ 450

7.2.8.3.2 Minimum motor cable lengths for motors with common winding system .......................................... 450

7.2.9 Booksize Base Cabinet / Booksize Cabinet Kits ..................................................................................... 451

7.2.9.1 Design ......................................................................................................................................... 451

7.2.9.2 Booksize Base Cabinet ................................................................................................................. 451

7.2.9.3 Booksize Cabinet Kits ................................................................................................................... 451

7.2.9.4 DC link fuses ................................................................................................................................ 452

7.2.9.5 Planning recommendations, special features ................................................................................. 452

7.2.10 Central Braking Modules ....................................................................................................................... 456

7.2.10.1 Design ......................................................................................................................................... 456

7.2.10.2 Position in the DC link configuration .............................................................................................. 459

7.2.10.3 DC Link fuses ............................................................................................................................... 459

7.2.10.4 Parallel configuration of Central Braking Modules .......................................................................... 459

7.2.10.5 Braking resistor ............................................................................................................................ 459

7.2.11 Auxiliary Power Supply Modules ........................................................................................................... 461

7.2.11.1 Design ......................................................................................................................................... 461

7.3 Liquid-cooled SINAMICS S120 Cabinet Modules ....................................................................................... 463

7.3.1 General configuring process ................................................................................................................... 463

7.3.2 Dimensioning information for liquid-cooled SINAMICS S120 Cabinet Modules ..................................... 464

7.3.2.1 Degrees of protection of liquid-cooled S120 Cabinet Modules ........................................................ 464

7.3.2.2 Required DC busbar cross-sections and maximum short-circuit currents ........................................ 464

7.3.2.3 Required cable cross-sections for line and motor connections ........................................................ 465

7.3.2.4 Cooling air requirements of liquid-cooled S120 Cabinet Modules.................................................... 467

7.3.2.5 Auxiliary power requirements ........................................................................................................ 468

7.3.2.6 Line reactors ................................................................................................................................ 471

7.3.2.7 Line Harmonics Filter .................................................................................................................... 472

7.3.2.8 Line filters .................................................................................................................................... 472

7.3.2.9 Parallel configuration .................................................................................................................... 473

7.3.2.10 Weights of S120 Cabinet Modules ................................................................................................ 473

7.3.3 Information about equipment handling of liquid-cooled units................................................................ 475

7.3.3.1 Customer terminal block ............................................................................................................... 475

7.3.3.2 Auxiliary voltage supply system ..................................................................................................... 475

7.3.3.3 DRIVE-CLiQ wiring ....................................................................................................................... 475

7.3.3.4 Erection of cabinets ...................................................................................................................... 476

7.3.3.5 Examples of Cabinet Modules arrangements ................................................................................. 477

7.3.3.6 Door opening angle ...................................................................................................................... 477

7.3.4 Information about the cooling circuit and the cooling circuit configuration .......................................... 478

7.3.4.1 Design of the liquid-cooled Cabinet Modules ................................................................................. 478

7.3.4.2 Required converter-side deionized water circuit ............................................................................. 478

7.3.4.3 Required plant-side raw water circuit ............................................................................................. 480

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7.3.4.4 Derating data of liquid-cooled S120 Cabinet Modules.................................................................... 480

7.3.4.5 Information about cooling circuit configuration ............................................................................... 481

7.3.4.6 Procedure of cooling circuit configuration ...................................................................................... 483

7.3.4.7 Example of a cooling circuit configuration ..................................................................................... 485

7.3.5 Basic Line Connection Modules ............................................................................................................. 489

7.3.5.1 Design ......................................................................................................................................... 489

7.3.5.2 DC link fuses ............................................................................................................................... 491

7.3.5.3 Parallel connections of Basic Line Connection Modules ................................................................ 491

7.3.6 Active Line Connection Modules ............................................................................................................ 492

7.3.6.1 Design ......................................................................................................................................... 492

7.3.6.2 DC link fuses ............................................................................................................................... 494

7.3.6.3 Parallel connections of Active Line Connection Modules ............................................................... 494

7.3.7 Motor Modules ........................................................................................................................................ 495

7.3.7.1 Design ......................................................................................................................................... 495

7.3.7.2 DC link fuses ............................................................................................................................... 497

7.3.7.3 Parallel connections of Motor Modules.......................................................................................... 497

7.3.7.3.1 General ....................................................................................................................................... 497

7.3.7.3.2 Minimum motor cable lengths for motors with common winding system ......................................... 497

7.3.8 Auxiliary Power Supply Modules ............................................................................................................ 498

7.3.8.1 Design ......................................................................................................................................... 498

7.3.9 Heat Exchanger Modules ........................................................................................................................ 500

7.3.9.1 Design and operating principle ..................................................................................................... 500

7.3.10 Braking Modules ................................................................................................................................... 503

8 Converter Cabinet Units SINAMICS S150 ..................................................................................... 504

8.1 General information ................................................................................................................................... 504

8.2 Rated data and continuous operation of the converters ........................................................................... 505

8.3 Factory settings (defaults) of customer interface on SINAMICS S150 with TM31 .................................... 509

8.4 Cable cross-sections and connections on SINAMICS S150 cabinet units................................................ 511

8.4.1 Recommended and max. possible cable cross-sections for line and motor connections ................. 511

8.4.2 Required cable cross-sections for line and motor connections ....................................................... 512

8.4.3 Grounding and PE conductor cross-section .................................................................................. 513

8.5 Precharging of the DC link and precharging currents .............................................................................. 513

8.6 Line-side components ............................................................................................................................... 514

8.6.1 Line fuses .................................................................................................................................... 514

8.6.2 Line filters .................................................................................................................................... 515

8.7 Components at the DC link ........................................................................................................................ 515

8.7.1 Braking units ................................................................................................................................ 515

8.8 Load-side components and cables............................................................................................................ 515

8.8.1 Motor reactors ............................................................................................................................. 515

8.8.2 dv/dt filters plus VPL .................................................................................................................... 516

8.8.3 Sine-wave filters .......................................................................................................................... 516

8.8.4 Maximum connectable motor cable lengths................................................................................... 516

8.9 Option L04 (Infeed Module dimensioned one rating class lower) ............................................................. 517

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9 Description of Options for Cabinet Units ......................................................................................519

9.1 Option G33 (CBE20 Communication Board) ................................................................................. 519

9.2 Option G51 – G54 (Terminal Module TM150) ............................................................................... 520

9.3 Option K82 (Terminal module for controlling the “Safe Torque Off” and “Safe Stop1” functions) ..... 522

9.4 Options K90 (CU320-2 DP), K95 (CU320-2 PN) and K94 (Performance expansion) ...................... 527

9.5 Option L08 (Motor reactor) / L09 (2 motor reactors in series) ......................................................... 528

9.6 Option L25 (Circuit breaker in a withdrawable unit design) ............................................................ 528

9.7 Option L34 (Output-side circuit breaker) ....................................................................................... 529

9.8 Option L37 (DC interface incl. precharging circuit) ........................................................................ 530

9.9 Option M59 (Closed cabinet doors) .............................................................................................. 531

9.10 Option Y11 (Factory assembly into transport units) ........................................................................ 532

10 General Information about Drive Dimensioning .........................................................................534

10.1 General ........................................................................................................................................ 534

10.2 Drives with quadratic load torque .................................................................................................. 535

10.3 Drives with constant load torque ................................................................................................... 537

10.4 Permissible motor-converter combinations .................................................................................... 538

10.5 Drives with permanent-magnet three-phase synchronous motors ................................................... 539

11 Motors ...........................................................................................................................................545

11.1 SIMOTICS SD & SIMOTICS TN series N-compact 1LA8 self-cooled asynchronous motors ............ 545

11.2 SIMOTICS TN series N-compact 1PQ8 forced-cooled asynchronous motors .................................. 545

11.3 SIMOTICS TN series N-compact 1LL8 open-circuit self-cooled asynchronous motors .................... 546

11.4 Converter-optimized SIMOTICS FD asynchronous motors ............................................................. 546

11.5 SIMOTICS TN series H-compact PLUS modular asynchronous motors .......................................... 550

11.6 SIMOTICS M compact asynchronous motors ................................................................................ 551

11.7 SIMOTICS HT series HT-direct 1FW4 synchronous motors with permanent magnets ..................... 551

11.8 Special insulation for higher line supply voltages at converter-fed operation ................................... 552

11.9 Bearing currents ........................................................................................................................... 553

11.10 Motor protection ........................................................................................................................... 553

Fundamental Principles and System Description

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1 Fundamental Principles and System Description

1.1 Operating principle of SINAMICS converters

1.1.1 General operating principle

The converters in the SINAMICS product range are PWM converters with a voltage-source DC link. At the input side,

the converter consists of a rectifier (shown in the schematic sketch as a thyristor rectifier) which is supplied with a

constant voltage VLine and a constant frequency fLine from a three-phase supply. The rectifier produces a constant DC

voltage VDCLink, i.e. the DC link voltage, which is smoothed by the DC link capacitors. The 2-level IGBT inverter on

the output side converts the DC link voltage to a three-phase system with a variable voltage VMotor and variable

frequency fMotor. This process operates according to the principle of pulse-width modulation PWM. By varying the

voltage and the frequency, it is possible to vary the speed of the connected three-phase motor continuously and

virtually without losses.

Block diagram of a PWM converter with voltage-source DC link

1.1.2 Pulse modulation method

The power semiconductors of the IGBT inverter (IGBT = Insulated Gate Bipolar Transistor) are high-speed, electronic

switches which connect the converter outputs to the positive or negative pole of the DC link voltage. The duration of

the gating signals in the individual inverter phases and the magnitude of the DC link voltage thus clearly determine

the output voltage and therefore also the voltage at the connected motor.

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If we consider all three phases, there is a total of 2³ = 8 switching states in the inverter, and the effect of these states

in the motor can be defined by voltage phasors.

Switching states of the

inverter

Phase

+ - -

+ + -

- + -

- + +

- - +

+ - +

+ + +

- - -

If, for example, phase L1 is connected to the positive DC link voltage, and phases L2 and L3 to the negative voltage

so as to produce switching state V1, the resultant voltage phasor points in the direction of motor phase L1 and is

designated phase I. The length of this phasor is determined by the DC link voltage.

Representation of resultant motor voltages as phasor

If the switching state changes from V1 to V2, then the voltage phasor rotates clockwise by an angle of 60°el. due to

the change in potential at terminal L2. The length of the phasor remains unchanged.

In the same way, the relevant voltage phasors are produced by switching combinations V3 to V

. Switching

combinations V7 and V8produce the same potential at all motor terminals. These two combinations therefore produce

voltage phasors of "zero" length (zero voltage phasor).

1.1.2.1 Generation of a variable voltage by pulse-width modulation

Voltage and frequency must be specified in a suitable way for a certain operating state of the motor, characterized by

speed and torque. Ideally, this corresponds to control of the voltage vector V(wt) on a circular path with the speed of

rotation w = 2 *p*f and adjusted absolute value. This is achieved through modulation of the actual settable voltage

space vectors (pulse-width modulation). In this way, the momentary value V(wt) is formed by pulses of the adjacent,

actual settable voltage space vectors and the voltage zero.

The solid angle is set directly by varying the ratio of the ON durations (pulse-width) of adjacent voltage vectors, the

desired absolute value by varying the ON duration of the zero voltage vector. This method of generating gating

signals is called space vector modulation SVM. It is used in all units described in this engineering manual. Space

vector modulation provides sine-modulated pulse patterns.

The following diagram illustrates how the voltages in phases L1 and L2 plus output voltage VL1-L2 (phase-to-phase

voltage) are produced by pulse-width modulation or space vector modulation and shows their basic time

characteristics. The frequency with which the IGBTs in the inverter phases are switched on and off is referred to as

the pulse frequency or clock frequency of the inverter.

Fundamental Principles and System Description

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Timing of the gating signal sequence for the IGBTs in the inverter phases L1 and L2 plus the associated output voltage

(phase-to-phase voltage) VL1-L2. The amplitude of the voltage pulses corresponds to the DC link voltage.

The diagram below shows the time characteristic (in blue) of one of the three output voltages of the inverter (phase-

to-phase voltage) and the resulting current (in black) generated in one of the three motor phases when a standard

asynchronous motor with a rated frequency of 50 Hz or 60 Hz is used and the inverter is operating with a pulse

frequency of 1.25 kHz. The diagram shows that the smoothing effect of the motor inductances causes the motor

current to be virtually sinusoidal, despite the fact that the motor is supplied with a square-wave pulse pattern.

Motor voltage (phase-to-phase) and motor current with space vector modulation

1.1.2.2 Maximum attainable output voltage with space vector modulation SVM

Space vector modulation SVM generates pulse patterns which approximate an ideal sinusoidal motor voltage through

voltage pulses with constant amplitude and corresponding pulse-duty factor. The peak value of the maximum

(fundamental) voltage that can be attained in this way corresponds to the amplitude of the DC link voltage VDCLink.

Thus the theoretical maximum motor voltage with space vector modulation which results is:

DCLink

SVM VV ×= 2

max

The amplitude of the DC link voltage VDCLink is determined by the method of line voltage rectification. With line-

commutated rectifiers used with SINAMICS G130 and G150 and also with S120 Basic Line Modules, it averages

1.41*VLine with no load, 1.35*VLine with partial load and 1.32*VLine.with full load. Thus with the true DC link voltage

amplitude of VDCLink ≈ 1.32*VLine at full load, the motor voltage theoretically attainable at full load with space vector

modulation without overmodulation is:

VSVM max = 0.935 * VLine .

As a result of voltage drops in the converter and minimum pulse times and interlock times in the gating unit

responsible for generating the IGBT gating pulse pattern, the values in reality are lower. In practice, therefore, the

value for space vector modulation without overmodulation must be assumed to be as follows:

VSVM max ≈ 0.92 * VLine

This value applies precisely to pulse frequencies of 2.0 kHz or 1.25 kHz according to the factory setting. At higher

pulse frequencies, it decreases by approximately 0.5 % per kHz.

Fundamental Principles and System Description

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1.1.2.3 Maximum attainable output voltage with pulse-edge modulation PEM

It is possible to increase the inverter output voltage above the values attained with space vector modulation (SVM) by

pulsing only at the edges of the fundamental-wave period rather than over the entire fundamental-wave period. This

process is referred to as pulse-edge modulation (PEM). The basic waveform of the motor voltage is then as shown

below.

Motor voltage with pulse-edge modulation PEM

The maximum possible output voltage is attained when clocking is performed with the fundamental frequency only,

i.e. when "pulsing" ceases altogether. The output voltage then consists of 120° rectangular blocks with the amplitude

of the DC link voltage. The fundamental frequency RMS value of the output voltage can then be calculated as:

LineLineDCLink

rect VVVV ×=××=×= 03.132.1

So it is possible with pure rectangular modulation to achieve a motor voltage which is slightly higher than the line

voltage. However, the motor voltage then has an unsuitable harmonic spectrum which causes major stray losses in

the motor and utilizes the motor inefficiently. It is for this reason that pure square-wave modulation is not utilized on

SINAMICS converters.

The pulse-edge modulation method used on SINAMICS converters permits a maximum output voltage which is only

slightly lower than the line voltage, even when allowance is made for voltage drops in the converter:

VPEM max ≈ 0.97 * VLine

The pulse-edge modulation method uses optimized pulse patterns which cause only minor harmonic currents and

therefore utilize the connected motor very efficiently. Commercially available standard asynchronous motors for

50 Hz or 60 Hz operation utilized according to temperature class 130 (previously temperature class B) in operation

directly on line can be utilized according to temperature class 155 (previously temperature class F) when operated

with pulse-edge modulation at the nominal operating point up to rated torque.

Pulse-edge modulation is available as standard in vector control mode (drive object of vector type) on all SINAMICS

units described in this engineering manual:

· SINAMICS G130 *) Chassis

· SINAMICS G150 *) Cabinets

· SINAMICS S150 *) Cabinets

· SINAMICS S120 *) Motor Modules / Chassis format

· SINAMICS S120 *) Motor Modules / Cabinet Modules format

For SINAMICS G130 and G150 converters, the modulator mode (parameter p1802) is automatically preset to value 9

(pulse-edge modulation) since "Pumps and fans" is the default technological application (parameter p0500 = 1). This

is because SINAMICS G converters are predominantly deployed in conjunction with asynchronous motors without

speed encoder as independent single drives for applications with simple control requirements. At a low output

frequency and low depth of modulation (output voltage < 92 % of input voltage), these converters utilize space vector

modulation SVM and switch over to pulse-edge modulation PEM automatically if the depth of modulation required at

higher output frequencies is so high that it can no longer be provided by space vector modulation SVM (output

voltage > 92 % of input voltage). The minor irregularities in the torque characteristic caused by transient phenomena

during transition between different modulation systems are virtually irrelevant for applications with simple control

requirements of the kind mentioned above.

Fundamental Principles and System Description

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Maximum attainable motor voltage with space vector modulation SVM and pulse-edge modulation PEM

For SINAMICS S120 Motor Modules and SINAMICS S150 converters, the modulator mode (parameter p1802) is

automatically preset to the value 4 (space vector modulation without overmodulation) in vector control mode because

the default technological application is "Standard drive vector" (parameter p0500 = 0). In this case, these units utilize

only space vector modulation SVM because, and this applies particularly to SINAMICS S120 Motor Modules, they

are predominantly used in coordinated multi-motor drive systems with sophisticated control technology which

demand very high control quality (e.g. strip finishing lines, paper-making machines and foil-drawing machines). These

types of application can rarely tolerate the minor irregularities in the torque characteristic caused by transient

phenomena during transition between different modulation systems. If SINAMICS S120 Motor Modules and

SINAMICS S150 converters are required to operate with pulse-edge modulation PEM, the modulator mode

(parameter p1802) must be set to 9 (pulse-edge modulation) during commissioning.

Basically, it would also be possible to achieve depths of modulation or output voltages in excess of 92 % through

overmodulation of the space vector modulation SVM (by setting parameter p1802 to values 0, 1, 2, 5, 6). While it is

possible by this method to prevent the slight irregularities in the torque characteristic on transition between

modulation systems, it also causes the harmonics spectrum in the motor current to increase, resulting in higher

torque ripples and higher motor losses. With a very high level of overmodulation (maximum modulation depth setting

in parameter p1803 > approx. 103 %), the control quality decreases significantly. Pulse-edge modulation PEM with its

optimized pulse patterns therefore offers obvious advantages in this case, as it enables a high depth of modulation

(high output voltage) combined with good drive behavior (in terms of torque accuracy and motor losses) to be

achieved.

*) Exceptions regarding the use of pulse-edge modulation:

Pulse-edge modulation must not be selected on converters with a sine-wave filter at the output.

If a Basic Infeed or a Smart Infeed is used to supply the inverter, the DC link voltage at full load is VDCLink = 1.32 x

VLine or V

DCLink = 1.30 x VLine. When space vector modulation without overmodulation (p1802=3) is selected and a

sine-wave filter is installed, the maximum motor voltage is then limited to approximately 85 % of the line input voltage

on converters with a supply voltage of 380 V - 480 V 3AC or to approximately 83 % of the line input voltage on

converters with a line supply voltage of 500 V - 600 V 3AC.

If the Infeed is an Active Infeed, the DC link voltage is as follows due to the operation of the Active Infeed in step-up

converter mode: VDCLink > 1.42 x VLine with factory setting VDCLink = 1.5 x VLine. When this factory setting for the Active

Infeed is used and space vector modulation without overmodulation (p1802=3) is selected and a sine-wave filter is

installed, the maximum motor voltage is limited to approximately 95 % of the line input voltage. Values of 100 % or

more can be achieved if the ratio VDCLink / VLine for the Active Infeed is parameterized to values higher than the factory

setting 1.5 as described in subsection "Active Infeed" of section "SINAMICS Infeeds and their properties".

Note:

Pulse-edge modulation PEM is available only for vector-type drive objects (vector and V/f control modes) in

combination with current controller clock cycles of ≥ 250 μs and is generally utilized on drives with asynchronous

motors. With servo-type drive objects (servo control mode), converters always operate with space vector modulation

SVM with automatic overmodulation. The reason for this is the slower dynamic response of the drive in operation with

pulse-edge modulation PEM. This is acceptable for many applications with vector control, but not for highly dynamic

applications with servo control.

Fundamental Principles and System Description

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1.1.3 The pulse frequency and its influence on key system properties

The pulse frequency of the inverter corresponds to the frequency at which the IGBTs are turned on and off in the

inverter phases in operation with space vector modulation SVM. It is an important parameter which has a significant

influence on various properties of the drive system. It can be varied within certain given limits. It might be useful to

increase the pulse frequency from the factory-set value in order, for example, to reduce motor noise. However, it

might also be essential to increase the pulse frequency, for instance, when higher output frequencies are required or

to allow the use of sine-wave filters at the converter output.

An overview of the following aspects of the pulse frequency is given below:

· The pulse frequency factory settings,

· the permissible pulse frequency adjustment limits,

· the interrelationships between current controller clock cycle, pulse frequency and output frequency,

· the effects of the pulse frequency on various properties of the drive system, and

· the important points to note in relation to motor-side options (motor reactors, motor filters).

1.1.3.1 Factory settings and ranges of pulse frequency settings

The factory setting of the pulse frequency fPulse of the motor-side inverter for SINAMICS G130, G150, S150 and S120

(Chassis and Cabinet Modules formats) with vector-type drive objects (vector and V/f control modes) is 2.0 kHz with a

current controller clock cycle TI = 250 μs or 1.25 kHz with a current controller clock cycle TI = 400 μs in accordance

with the following table.

Line supply voltage Output power Rated

output current

Factory setting of

pulse frequency fPulse

and current controller

clock cycle T

Maximum possible

pulse frequency of power

unit

380 V to 480 V 3AC ≤ 250 kW ≤ 490 A 2.00 kHz / 250 μs8.0 kHz

≥ 315 kW ≥ 605 A 1.25 kHz / 400 μsUnit-specific 7.5 or 8.0 kHz

500 V to 600 V 3AC All power ratings All currents 1.25 kHz / 400 μs7.5 kHz

660 V to 690 V 3AC All power ratings All currents 1.25 kHz / 400 μs7.5 kHz

1) Details can be found in Catalogs D 11 and D 21.3 and in the chapters about specific unit types in this manual

Unit-specific factory setting of pulse frequency and current controller clock cycle for SINAMICS G130, G150, S150 and for

SINAMICS S120 Motor Modules (Chassis and Cabinet Modules formats) for vector-type drive objects (vector and V/f

control modes)

The pulse frequency factory setting can be increased in discrete steps. The possible settings for the pulse frequency

fPulse are dependent upon the current controller clock cycle setting TI according to the following equation

fPulse = n • (1 / TI) where n = ½, 1, 2, 3, ... .

In addition the limits given by the relevant power units according to the table above, as well as the current derating

factors specified in the chapters about specific unit types must be taken into account. Depending on these criteria,

the pulse frequency can therefore be raised to 8 kHz or 7.5 kHz, depending on the unit type. It is possible to switch at

any time between pulse frequencies, which are calculated for a constant current controller clock cycle setting

according to the equation given above, for vector-type drive objects (vector and V/f control modes), even when the

unit is in operation, by changing a parameter setting or switching to another data set, for example. By altering the

current controller clock cycle, it is also possible to set different pulse frequency values, in other words, the pulse

frequency can be very finely adjusted. However, the current controller clock cycle can be changed only when the

drive is in commissioning mode.

1.1.3.2 Interrelationships between current controller clock cycle, pulse frequency and output

frequency

For SINAMICS G130, G150, S150 and S120 converters and inverters (Chassis and Cabinet Modules formats)

described in this engineering manual and vector-type drive objects (vector and V/f control modes), the following

interdependencies exist between the current controller clock cycle, the pulse frequency and the output frequency:

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Dependence of the settable pulse frequency fPulse on the current controller clock cycle setting TI:

fPulse = n • (1 / TI) where n = ½, 1, 2, 3, … .(applies to vector and V/f control modes) (1)

Dependence of the maximum attainable output frequency fout max on the current controller clock cycle setting TI:

fout max ≤ 1 / (8.3333 • TI) . (applies only to vector control mode but not to V/f control mode) (2)

Dependence of the maximum attainable output frequency fout max on the pulse frequency setting fPulse:

fout max ≤ fPulse / 12 . (applies to vector and V/f control modes) (3)

Regardless of the formulas specified above, the maximum possible output frequency fout max is limited to 550 Hz in

the standard firmware for the vector and U/f control modes with SINAMICS G and S. With the license "High output

frequency" (6SL3074-0AA02-0AA0) for SINAMICS S (which can also be ordered as option J01 for the SINAMICS S

CompactFlash card), it is now possible to increase the maximum possible output frequency fout max to 650 Hz. The

"High output frequency" license is subject to export restrictions. Further information is available on request.

When firmware version 4.3 is used, the minimum settable current controller clock cycle is 250 μs for vector-type drive

objects (vector and V/f control modes) of all SINAMICS G and SINAMICS S Chassis and cabinet units.

When firmware version 4.4 or higher is used, a minimum current controller clock cycle of 125 μs can be set for

vector-type drive objects (vector and V/f control modes) of SINAMICS S Chassis and cabinet units. The only

exceptions are the parallel connections of SINAMICS S converters for which the minimum permissible current

controller clock cycle is 200 μs. For SINAMICS G converters, the minimum permissible current controller clock cycle

setting remains 250 μs and the minimum permissible speed controller clock cycle is also unchanged at 1 ms.

Vector-type drive object with vector control mode

For vector control mode the table below shows the settable pulse frequencies fPulse and the associated maximum

attainable output frequencies fout max as a function of the current controller clock cycle setting TI in accordance with

equations (1) to (3) (which must all be satisfied simultaneously).

Current

controller

clock cycle

Settable pulse frequencies and associated max. output frequencies (exact, non-rounded values)

125 μs

(FW version 4.4

or higher

for SINAMICS S)

4.00 kHz

333 Hz

8.0 kHz

550 Hz /

650 Hz 1

200 μs

(FW version 4.4

or higher

for SINAMICS S)

2.50 kHz

208 Hz

5.00 kHz

416 Hz

250 μs2

SINAMICS G + S

2.00 kHz

166 Hz

4.00 kHz

333 Hz

8.0 kHz

480 Hz

400 μs3

SINAMICS G + S

1.25 kHz

104 Hz

2.50 kHz

208 Hz

5.00 kHz

300 Hz

7.5 kHz

300 Hz

500 μs

SINAMICS G + S

1.00 kHz

83 Hz

2.00 kHz

166 Hz

4.00 kHz

240 Hz

6.00 kHz

240 Hz

8.0 kHz

240 Hz

1Only with the license "High output frequency" that is available as option J01 for the SINAMICS S CompactFlash card

2 The factory settings for current controller clock cycle and pulse frequency are 250 μs and 2.00 kHz respectively for the SINAMICS

G and S converters below:

- 380 V – 480 V 3AC: ≤ 250 kW / 490 A or 510 V – 720 V DC: ≤ 250 kW / 490 A

3 The factory settings for current controller clock cycle and pulse frequency are 400 μs and 1.25 kHz respectively for the SINAMICS

G and S converters below:

- 380 V – 480 V 3AC: ≥ 315 kW / 605 A or 510 V – 720 V DC: ≥ 315 kW / 605 A

- 500 V – 600 V 3AC: All power ratings or 675 V – 900 V DC: All power ratings

- 660 V – 690 V 3AC: All power ratings or 890 V – 1035 V DC: All power ratings

In the vector-type drive object with vector control mode settable pulse frequencies and associated maximum attainable

output frequencies as a function of the current controller clock cycle setting for SINAMICS G130, G150, S150 and S120 in

Chassis and Cabinet Modules formats.

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Vector-type drive object with V/f control mode

For V/f control mode the table below shows the settable pulse frequencies fPulse and the associated maximum

attainable output frequencies fout max as a function of the current controller clock cycle setting TI in accordance with

equations (1) and (3) on the previous page (which must all be satisfied simultaneously).

Current controller

clock cycle Settable pulse frequencies and associated max. output frequencies (exact, non-rounded values)

125 μs

(FW version ≥ 4.4

for SINAMICS S)

4.00 kHz

333 Hz

8.0 kHz

550 Hz /

650 Hz 1

200 μs

(FW version ≥ 4.4

for SINAMICS S)

2.50 kHz

208 Hz

5.00 kHz

416 Hz

250 μs2

SINAMICS G + S

2.00 kHz

166 Hz

4.00 kHz

333 Hz

8.0 kHz

550 Hz /

650 Hz 1

400 μs3

SINAMICS G + S

1.25 kHz

104 Hz

2.50 kHz

208 Hz

5.00 kHz

416 Hz

7.5 kHz

550 Hz /

623 Hz 1

500 μs

SINAMICS G + S

1.00 kHz

83 Hz

2.00 kHz

166 Hz

4.00 kHz

333 Hz

6.00 kHz

500 Hz

8.0 kHz

550 Hz /

650 Hz 1

1Only with the license "High output frequency" that is available as option J01 for the SINAMICS S CompactFlash card

2 The factory settings for current controller clock cycle and pulse frequency are 250 μs and 2.00 kHz respectively for the SINAMICS

G and S converters below:

- 380 V – 480 V 3AC: ≤ 250 kW / 490 A or 510 V – 720 V DC: ≤ 250 kW / 490 A

3 The factory settings for current controller clock cycle and pulse frequency are 400 μs and 1.25 kHz respectively for the SINAMICS

G and S converters below:

- 380 V – 480 V 3AC: ≥ 315 kW / 605 A or 510 V – 720 V DC: ≥ 315 kW / 605 A

- 500 V – 600 V 3AC: All power ratings or 675 V – 900 V DC: All power ratings

- 660 V – 690 V 3AC: All power ratings or 890 V –1035 V DC: All power ratings

In the vector-type drive object with V/f control mode settable pulse frequencies and associated maximum attainable output

frequencies as a function of the current controller clock cycle setting for SINAMICS G130, G150, S150 and S120 in Chassis

and Cabinet Modules formats.

Notes:

· The maximum attainable output frequency value for SINAMICS S converters described in this engineering

manual for vector-type drive objects in vector control mode is 550 Hz. With the license "High output

frequency", it is possible to increase the output frequency to maximum 650 Hz for SINAMICS S units. To

achieve this output frequency, a power unit is required which is designed for a maximum pulse frequency of

8.0 kHz and is not operated in a parallel connection, and a current controller clock cycle of 125 μs (settable

on SINAMICS S with firmware version 4.4 or higher). In the case of power units which are designed for a

maximum pulse frequency of only 7.5 kHz and are not operated in a parallel connection, the maximum

attainable output frequency is 623 Hz. To obtain this output frequency, a current controller clock cycle of

133.75 μs is required (settable on SINAMICS S with firmware version 4.4 or higher) and a pulse frequency

of 7.477 kHz.

· By altering the current controller clock cycle in the range between 125 μs and 500 μs (with SINAMICS S) or

250 μs and 500 μs (with SINAMICS G), it is possible to set other pulse frequency values than those stated in

the table above, although it must be noted that the three equations (1) to (3) on the previous page must still

all be satisfied simultaneously. However, when units communicate in isochronous mode (e.g. via

isochronous PROFIBUS), the only permissible current controller clock cycle is 125 μs or whole multiples

thereof. Furthermore, the current controller clock cycle must be selected such that the set bus clock cycle

also corresponds to a whole multiple of the current controller clock cycle. When SINAMICS Link is used, bus

clock cycles of 500 μs, 1000 μs or 2000 μs can be set which means that the following current controller

clock cycles can be selected: 125 μs, 250 μs and 500 μs. For further information, refer to the function

manual "SINAMICS S120 Drive Functions" and the List Manuals.

· When the pulse frequency is set higher than the relevant factory setting, the current derating factors

applicable to the specific unit must be observed. These can be found in the chapters on specific unit types.

· If multiple Motor Modules (axes) are to be controlled by a single CU320-2 Control Unit in SINAMICS S multi-

motor drives, it must be noted that the maximum possible number of Motor Modules (axes) is dependent

upon the current controller clock cycle. More detailed information can be found in section "Determination of

the required control performance of the CU320-2 Control Unit" in chapter "General Information about Built-in

and Cabinet Units SINAMICS S120".

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1.1.3.3 Influence of the pulse frequency on the inverter output current

The pulse frequency factory setting of either 2.0 kHz or 1.25 kHz is relatively low in order to reduce inverter switching

losses. If the pulse frequency is increased the inverter switching losses and thus also the total losses in the converter

increase accordingly. The result would be overheating of the power unit when operating at full load capacity. For this

reason, the conducting losses must be lowered in order to compensate for the increase in switching losses. This can

be achieved by reducing the permissible output current (current derating). The current derating factors as a function

of pulse frequency are unit-specific values and must be taken into account when the converter is dimensioned. The

derating factors for various pulse frequencies can be found in the chapters on specific unit types. If derating factors

are required for pulse frequencies which are not included in the tables, they can be calculated by linear interpolation

between the stated table values. Under certain boundary conditions (line voltage at low end of permissible wide-

voltage range, low ambient temperature, restricted speed range), it is possible to partially or completely avoid current

derating at pulse frequencies which are twice as high as the factory setting. For further information, please refer to

section "Operation of converters at increased pulse frequency".

1.1.3.4 Influence of the pulse frequency on losses and efficiency of inverter and motor

With the factory-set pulse frequency of 2.0 kHz or 1.25 kHz, the motor current is already close to sinusoidal. The

stray losses in the motor caused by harmonic currents are low, but not negligible. Commercially available standard

motors for 50 Hz or 60 Hz operation utilized according to temperature class 130 (previously temperature class B) in

operation directly on line can be utilized according to temperature class 155 (previously temperature class F) at the

nominal working point up to rated torque when operated on a converter. The winding temperature rise is then

between 80 and 100 K.

Raising the pulse frequency on standard motors for 50 Hz or 60 Hz reduces the motor stray losses only slightly, but

results in a considerable increase in the converter switching losses. The efficiency of the overall system (converter

and motor) deteriorates as a result.

1.1.3.5 Influence of the pulse frequency on the motor noise

A higher level of magnetic motor noise is excited when three-phase motors are operated on PWM converters as

compared to operation directly on line at 50/60 Hz supply systems. This is caused by the voltage pulsing which

results in additional voltage and current harmonics.

According to

· IEC/TS 60034-17:2006 "Rotating electrical Machines – Part 17: Cage induction motors when fed from converters

- Application guide“,

and

· IEC/TS 60034-25:2007 "Rotating electrical Machines – Part 25: Guidance for the design and performance of a.c.

motors specifically designed for converter supply",

the A-graded noise pressure level increases up to 15 dB(A) when three-phase motors are operated on a PWM

converter up to rated frequency as compared to motors of the same type operating on pure sinusoidal voltage.

The actual values depend on the PWM method used and the pulse frequency of the converter on the one hand, and

the design and number of poles of the motor on the other.

In the case of SINAMICS converters operating in vector control mode (drive object of vector type) at the factory-set

pulse frequency (1.25 kHz or 2.0 kHz), the increase in A-graded noise pressure level produced by the motor as a

result of the converter supply is typically within the 5 dB(A) to 10 dB(A) range.

The diagram below shows the scatter range of the increase in the A-graded noise pressure level ΔLpfA produced by

the motor in converter-fed operation as compared to operation directly on line at a 50 Hz supply system. This applies

to fin-cooled motors with 2, 4, 6 and 8 poles operating at the factory-set pulse frequency of 1.25 kHz or 2.0 kHz. The

values are lower for water-jacket-cooled motors and SIMOTICS TN series H-compact PLUS motors.

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Increase in motor noise at operation on the factory-set

pulse frequency of 1.25 kHz or 2.0 kHz

Reduction in motor noise through increase in pulse frequency

Increasing the pulse frequency generally reduces the rise in the motor noise level associated with converter-fed

operation.

The following diagram illustrates the scatter range of the increased A-graded sound pressure level ΔLpfA produced by

the motor in comparison to the level measured when the motor is operating directly on a 50 Hz supply system. This

applies to fin-cooled motors with 2, 4, 6 and 8 poles operating at pulse frequencies above the factory setting, i.e. at

2.5 kHz or 4.0 kHz. The values are lower for water-jacket-cooled motors and SIMOTICS TN series H-compact PLUS

motors.

Increase in motor noise at pulse frequencies higher than the factory setting, i.e. at 2.5 kHz or 4.0 kHz

It is important to note, however, that higher pulse frequencies also necessitate current derating for the inverter. In

addition to the current derating required for higher pulse frequencies, other restrictions associated with motor-side

options (such as motor reactors, dv/dt filters and sine-wave filters) must also be taken into account where applicable.

Under certain boundary conditions (line voltage at the low end of the permissible wide-voltage range, low ambient

temperature, restricted speed range), it is possible to partially or completely dispense with current derating for pulse

frequencies which are up to twice as high as the factory setting. Further details can be found in section "Operation of

converters at increased pulse frequency".

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In the case of pump and fan applications with square-law load characteristic, current derating can be dispensed with

at certain pulse frequencies that are higher than the factory setting.

For pump and fan applications with low control requirements ("Pumps and fans" selected as the technological

application with parameter setting p0500 = 1), the modulator mode (parameter p1802) is automatically preset to 9

(pulse-edge modulation) for SINAMICS G converters, and can also be set to the same value for SINAMICS S units.

The SINAMICS inverters then utilize space vector modulation SVM at a low output frequency and thus also a low

output voltage of less than around 92 % of the input voltage, and then automatically switch over to pulse-edge

modulation PEM if a higher output frequency and thus an output voltage of more than about 92 % of the input voltage

is required, but can no longer be provided by space vector modulation.

Owing to the square law relationship between torque (M) and speed (n), the point at which an inverter switches

between space vector modulation SVM and pulse-edge modulation PEM corresponds to a motor current that equals

approximately 83 % of the nominal motor current.

Switchover between Space Vector Modulation and Pulse-Edge Modulation on drives with square-law load characteristic

M~n2

On the condition that the current derating factor of the inverter for a specific pulse frequency higher than the factory

setting is greater than or equal to the percentage motor current at the point of switchover, switchover can be

achieved even at the higher pulse frequency without the risk of initiating an overload reaction.

Above the switchover point, the inverter operates with pulse-edge modulation using optimized pulse patterns which

involve a significantly smaller number of switching operations than space vector modulation. As a result, the effective

pulse frequency utilized by the inverter in pulse-edge modulation mode is significantly lower than the pulse frequency

in space vector modulation mode and is within the range of the factory setting. It is for this reason that the motor can

reach its nominal operating point in pulse-edge modulation mode without initiating an overload reaction.

Because of these interlinked factors, all SINAMICS G130 and G150 converters, for example, which have a pulse

frequency factory setting of 1.25 kHz can be operated with a pulse frequency setting of 2.0 kHz in pump and fan

applications with square-law load characteristic without the need for current derating, as the current derating factor

for these converters is generally ≥ 83 % for 2.0 kHz.

Note:

The interlinked factors described above are relevant in cases where the rated motor voltage is equal to the rated line

voltage and the converter is operating at rated line voltage. At higher line voltages, the point of switchover between

space vector modulation and pulse-edge modulation occurs at higher speeds or outputs. For this reason, the

procedure described can be meaningfully applied only in cases where the drive is operating on a supply system with

a rated voltage that never or only rarely exceeds the rated motor voltage by any significant amount.

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Reduction in motor noise through load-dependent pulse frequency switchover

If current derating and associated overdimensioning of the converter which are necessitated by a continuously

increase in the pulse frequency are not acceptable for economic reasons, an alternative option in vector control mode

(drive object of vector type) is to switch over pulse frequencies as a function of load or speed while the converter is

running. This measure is especially effective for pump and fan drives with a square-law speed/torque characteristic.

In this case, the converter can operate at a higher pulse frequency in the partial-load range. When the load or speed

reaches a limit that is individually defined for each drive, the pulse frequency factory setting is reactivated again in

response to a data set switchover. In this way, the motor noise can be reduced to a lower level over most of the

speed setting range. The motor noise increases only in the rated load range, which normally represents only a small

percentage of the overall operation time of the drive.

Reduction in motor noise through flux decrease (efficiency optimization)

The factory settings of SINAMICS converters are devised such that they can operate motors at rated flux over the

entire base speed range up to rated speed. This setting is essential for constant-torque drives. In the case of pump

and fan drives with a square-law speed/torque characteristic, however, it is generally possible to reduce the motor

flux in the partial-load range. In addition to reducing the losses in the converter and motor, decreasing the flux is

generally also effective in attenuating the additional motor noise caused by the converter. The flux setting is a

parameterizable quantity (P1580).

Reduction in motor noise through pulse frequency wobbling

"Pulse frequency wobbling" can be activated via parameter p1810 / Bit 02 = 1 for Chassis units and cabinet units (not

possible on earlier units with CIB module and CU320 Control Unit with firmware versions < 2.6). The wobble

amplitude is set in parameter p1811. Pulse frequency wobbling uses a statistical method to vary the pulse frequency

according to the setting in parameter p1811. The mean pulse frequency value still corresponds to the set value, but

the statistical variation of the momentary value produces a modified noise spectrum. The subjectively perceptible

motor noise diminishes as a result, especially at the relatively low factory-set pulse frequencies. For further details

about parameter assignments, please refer to the function manual "SINAMICS S120 Drive Functions" and the list

manuals.

Note:

§ Pulse frequency wobbling can be activated only on power units in Chassis format.

§ Pulse frequency wobbling is possible only in the vector and V/f control modes, but not in servo control mode.

§ The maximum pulse frequency fPulse max with wobbling equals fPulse max = 1/current controller clock cycle,

i.e.:

fPulse max = 4 kHz with current controller clock cycle of 250 μs and fPulse max = 2.5 kHz with current controller

clock cycle of 400 μs.

§ Pulse frequency wobbling is not possible with current controller clock cycles of < 250 μs

1.1.3.6 Correlation between pulse frequency and motor-side options

If motor reactors, dv/dt filters plus VPL, dv/dt filters compact plus VPL or sine-wave filters are installed at the

converter output, the maximum permissible pulse frequency and the maximum output frequency are limited by these

options. In some cases, a fixed pulse frequency is specified:

· Permissible pulse frequency with motor reactor (SINAMICS):

The maximum pulse frequency is limited to twice the value of the factory setting, i.e. to 4 kHz on units with

factory setting 2 kHz and to 2.5 kHz on units with factory setting 1.25 kHz. The maximum output frequency is

limited to 150 Hz independent of the selected pulse frequency.

· Permissible pulse frequency with dv/dt filter plus VPL and dv/dt filter compact plus VPL (SINAMICS)

The maximum pulse frequency is limited to twice the value of the factory setting, i.e. to 4 kHz on units with

factory setting 2 kHz and to 2.5 kHz on units with factory setting 1.25 kHz. The maximum output frequency is

limited to 150 Hz independent of the selected pulse frequency.

· Permissible pulse frequency with sine-wave filter (SINAMICS):

Sine-wave filters are available for voltage levels 380 V to 480 V 3AC and 500 V to 600 V 3AC. The pulse

frequency is a mandatory fixed value and equals 4 kHz (380 V to 480 V) or 2.5 kHz (500 V to 600 V). The

maximum output frequency is limited to 150 Hz (380 V – 480 V) or 115 Hz (500 V – 600 V).

· Permissible pulse frequency with sine-wave filter (external supplier):

The pulse frequency and maximum output frequency must be set according to the filter manufacturer's

instructions.

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1.1.4 Open-loop and closed-loop control modes

The standard firmware of the SINAMICS converters of type G130, G150, S120 and S150 described in this manual

offers a range of different open-loop and closed-loop control modes for three-phase motors:

· V/f open-loop control modes for applications with simple control requirements

· Field-oriented closed-loop control modes for applications which require highly precise and highly dynamic

control functionality

1.1.4.1 General information about speed adjustment

The steady-state speed/torque characteristic of an asynchronous motor can be shifted in converter-fed operation

through adjustment of the frequency and voltage, as illustrated in the diagram below. The speed/torque characteristic

in "bold" print represents the motor's characteristic when it is operating directly on the mains supply at rated

frequency frated and rated voltage Vrated.

Shifting the speed/torque characteristic of an asynchronous motor by adjusting frequency and voltage

As long as the voltage is adjusted in proportion to the frequency, the ratio between voltage and frequency remains

constant and thus also the magnetic flux, the available torque and the stalling torque of the motor. This is known as

the constant flux range or the base speed range.

If the frequency is increased further after the maximum possible output voltage of the converter has been reached,

the ratio between voltage and frequency decreases again and thus also the magnetic flux in the motor. This is known

as the field-weakening range. With asynchronous motors operating in the field weakening range, the available torque

M decreases in relation to the rated torque Mrated approximately in proportion to the ratio frated/f. The output power

remains constant. The stalling torque in the field-weakening range Mk-reduced decreases in relation to the stalling

torque Mk in the constant flux range in proportion to the ratio (frated/f)2.

1.1.4.2 V/f control modes

V/f control is a simple method of adjusting the speed of three-phase motors. V/f control is based on the principle of

varying the frequency in order to adjust the motor speed, while at the same time applying a voltage setpoint

according to the characteristic of the V/f curve selected in the firmware. The gating unit generates pulse patterns to

control the IGBTs in the three phases of the converter's power unit.

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Diagram of the basic structure of the V/f control method

The voltage is adjusted as a function of frequency according to the V/f characteristic with the aim of maintaining the

motor flux as constantly as possible at the rated flux value, irrespective of speed or frequency.

At low frequencies, the ohmic stator resistance of the motor in relation to inductance is not negligible, which means in

this case that the voltage of the V/f characteristic must be boosted relative to the linear curve in order to compensate

for the voltage drop across the stator resistance.

At high frequencies, the maximum possible output voltage Vmax of the converter is reached, resulting in a horizontal

knee point in the V/f characteristic. The knee point generally corresponds to the rated operating point of the

connected motor. If the frequency is further increased beyond the knee point, the ratio between voltage and

frequency decreases due to the constant voltage. The motor flux is then also reduced, causing the motor to operate

in the field-weakening range.

V/f control modes are available in the standard firmware of the SINAMICS converters described in this engineering manual

(SINAMICS G130, G150, S120, S150) in the vector drive object. The following V/f control modes can be selected:

· V/f control with linear characteristic

· V/f control with parabolic characteristic

· V/f control with freely parameterizable characteristic

· V/f control for high-precision frequency-controlled drives in the textiles sector

· V/f control with independent voltage setpoint

In order to optimize the performance of drives operating in V/f control mode, the following functions have been

provided in the SINAMICS firmware:

· Slip compensation: For the purpose of increasing accuracy of speed, the frequency is adapted as a function

of load current in order to compensate the slip of the connected asynchronous motor.

· Flux current control (FCC): For the purpose of increasing accuracy of speed, voltage and flux are adapted

as a function of load.

· Resonance damping: The resonance damping function dampens electromechanical oscillations in the

frequency range up to a few tens of hertz.

· Current limiting control: The current limiting control prevents the connected asynchronous motor from

stalling and thus functions as stall protection.

The advantages of the V/f control method lie in its simplicity and its ability to withstand parameter fluctuations, such

as changes in resistance caused by temperature rise or changeover of the motor operating on the converter.

Furthermore, this control method fully supports converter-fed operation of multi-motor drives. Its disadvantages lie in

its lack of precision and dynamic response, particularly at low speeds and in the field weakening range.

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In view of these properties, use of the V/f control method is recommended primarily for asynchronous motor drives

with low requirements of accuracy and dynamic response, and for asynchronous motor drives with limited speed

range and low torque requirements at low speeds. The V/f control method can be usefully employed up to an output

power of about 100 kW – 200 kW, and for multi-motor drives with asynchronous or SIEMOSYN motors. The higher

the motor power, the greater the tendency to oscillate at low frequencies. For this reason, drives of this type need to

be commissioned carefully. This applies in particular to the resonance damping function.

1.1.4.3 Field-oriented control modes

Field-oriented control is a sophisticated method of controlling three-phase motors. With field-oriented control, the

equations which describe the motor are not referred to the fixed coordinate system of the stator (α-β coordinates), but

instead to the rotating magnetic field of the rotor (d-q coordinates). In this rotating coordinate system which is rotor-

field-orientated, the stator current can be split into two components, i.e. the field-producing component Id and the

torque-producing component Iq.

· The field-producing current component Id is responsible for the magnetic field in the motor and is thus

comparable to the excitation current in a DC motor.

· The torque-producing current component Iq is responsible for the motor torque and is thus comparable to

the armature current in a DC motor.

The resulting control structure is therefore comparable to the DC motor. Thanks to the independent and direct control

of the field-producing current component Id and the torque-producing current component Iq, a high degree of

accuracy and, more importantly, an excellent dynamic response are achieved with this control method.

The diagram below illustrates the basic structure of the field-oriented control method for an asynchronous motor.

Diagram of the basic structure of the field-oriented control method for an asynchronous motor

The three measured actual motor current values IL1, IL2 and IL3 are converted into the two current components Id act

and Iq act of the rotating d-q coordinate system by means of a motor model which includes a coordinate transformation

(CT). The values of Id act and Iq act are constant in the case of a symmetrical three-phase system in the motor with

purely sinusoidal motor currents which are out of phase by 120° in each case. They are compared to their setpoints

(Id set and Iq set respectively) and applied to the Id current controller and Iq current controller respectively. The

controller outputs provide the two voltage components Vd set and Vq set in the rotating d-q coordinate system. The

following coordinate transformation (CT) converts the two voltage components into the fixed α-β coordinate system.

The angle ρ between the rotating d-q coordinate system and the fixed α-βcoordinate system, which is required to

convert the coordinates, is calculated by the motor model. Using the two voltage components Vα and Vβ, the gating

unit generates pulse patterns to control the IGBTs in the three phases of the power unit of the converter.

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On drives which require a very high degree of precision, especially at very low speeds down to zero speed, or drives

which demand an excellent dynamic response, the actual speed value nact is generally measured by a speed encoder

(E) and then passed to the motor model and the speed controller. Drives without high requirements of precision

and/or dynamic response do not need a speed encoder. In this case the actual speed value nact calculated is computed

by the motor model and used instead of the speed encoder signal (encoderless control).

The quality of the field-oriented control critically depends on precise knowledge of the position of the magnetic field in

the motor and thus on the quality of the motor model. Only with precise field orientation direct and independent

access to the magnetic field and the torque is possible. For this reason, the motor model must be precisely tuned to

the connected motor. This tuning is part of the drive commissioning process. The rating plate data of the motor must

be input first. The motor is then automatically identified by the converter itself (measurements when motor is at

standstill and when motor is rotating).

Two types of field-oriented control modes are available for SINAMICS converters:

Vector control

Vector control is available as drive object of vector type in the standard firmware of all the SINAMICS converters

described in this engineering manual (SINAMICS G130, G150, S120, S150). The following vector control modes can

be selected:

· Speed control with and without encoder (only TTL / HTL incremental encoders may be used as encoders for

SINAMICS G130 / G150 converters)

· Torque control with and without encoder (only TTL / HTL incremental encoders may be used as encoders

for SINAMICS G130 / G150 converters)

The advantages of vector control lie in its very high torque accuracy and its high dynamic response. Relatively high

complexity as well as significant sensitivity to parameter fluctuations, such as changes in resistance caused by

temperature rise, are the disadvantages of this control mode. To achieve particularly high accuracy over the entire

speed range, therefore, it is important that the motor identification process is performed properly, that the effects of

temperature rise are compensated by use of a KTY motor temperature sensor and that friction compensation based

on recording of the friction characteristic is provided if necessary.

The control characteristics, such as rise times, accuracy, ripple, etc., as a function of current controller cycle settings

and motor types used can be found in the sections on specific unit types.

Typical applications for vector control are speed-controlled asynchronous motor drives with very high speed and

torque stability in general machine engineering, such as those employed, for example, on paper-making machines,

winders, coilers and lifting gear. However, permanent-magnet synchronous motors and separately excited

synchronous motors can also be operated in vector control mode.

Servo control

Servo control is available as drive object of servo type in the standard firmware of all SINAMICS S120 units. The

following servo control modes can be selected:

· Speed control with and without encoder

· Torque control with encoder

· Position control with encoder

The advantages of servo control lie in its outstandingly high dynamic response, especially in cases where it is

possible to parameterize very short current controller cycles of < 250 μs. Its disadvantage lies in its torque accuracy

which is lower than that provided by vector control.

The control characteristics, such as rise times, accuracy, ripple, etc., as a function of current controller cycle settings

and motor types used can be found in chapter "General Information about Built-in and Cabinet Units SINAMICS

S120".

Typical applications for servo control are drives with highly dynamic motion control, such as those used in machine

tools, clocked production machines and industrial robots.

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1.1.4.4 A comparison of the key features of open-loop and closed-loop control modes

The following table shows an overview of the key features of the three open-loop and closed-loop control modes.

Main features V/f control Vector control Servo control

Drive characteristic Simple control Precise torque controller Precise position controller

Control model - Dimensioned for accuracy Dimensioned for dynamic

response

Main applications

Drives with low requirements of

dynamic response and accuracy.

Highly synchronized multi-motor

drives, e.g. on textile machines

with SIEMOSYN motors

Speed-controlled drives with

extremely high torque accuracy.

For universal application in

general machine engineering.

Ideal for operation of motors

without encoder.

Drives with highly dynamic

motion control.

For use on machine tools and

clocked production machines.

Dynamic response

- without encoder

- with encoder

Low

Medium

High

Medium

Very high

Torque accuracy

- without encoder

- with encoder

High

Very high

Medium

Key features of different open-loop and closed-loop control modes on SINAMICS converters

1.1.4.5 Load balance on mechanically coupled drives

General

For many applications mechanically coupled drives are used. In this case, the mechanical coupling can be rigid, as it

is for example with a roller that is driven by two identical motors, or flexible as in the example of a conveyor belt for

material handling which is driven by a mechanical grouping of multiple motors. Both types of coupling require load

balance in order to distribute the entire mechanical load in a controlled manner and in defined proportions among the

individual drives.

With a rigid coupling, the motors are rigidly coupled with one another by the mechanical system, for example, with

rollers and gears.

As a result of the rigid coupling, it is essential that all motors operate at an identical speed. Since identical motors are

normally used in couplings of this kind, the torques generated by the motors should also be identical. This can be

ensured only by providing a load balance between the drive systems. An uneven load distribution between the

motors can otherwise develop. In the worst-case scenario, the load might be braked continuously by one motor but

constantly accelerated by the other.

Flexibly coupled motors are intercoupled only by means of a material conveyor which generally exhibits a certain

elasticity.

But there are also limits to this elasticity. If one motor applies a stronger pulling force to the material than applied by

the other motor, the material tension and thus also the mechanical tension can alter significantly. This can have an

effect on the entire process and even damage the material or other equipment. This is why load balance is also

required for flexibly coupled motors.

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Load-balance control

There are various methods by which the load or the torque can be balanced between different drives. The simplest

method is to transfer the torque setpoint of the master drive to the slave drive and to deactivate the speed controller

on the slave drive. This is possible, however, only if it can be safely assumed that the mechanical coupling between

the drives can never be interrupted. But this is rarely true because the mechanical coupling is generally created by

pressure (with calenders, for example) or by other connecting elements such as belts, wires or material conveyors

(webs). It therefore has to be assumed that this coupling can be interrupted in an uncontrolled manner when certain

boundary conditions are fulfilled. For this reason, it must be possible to maintain the drive in a safe state if the

coupling were to be interrupted. The drive must never be allowed to accelerate in an uncontrolled manner and

potentially reach or even exceed critical speeds. The best way to safeguard against this risk is to keep the speed

controller of the slave drive activated.

Simple load-balance control can already be implemented using BICO technology or the technology controller. The

load balancing controls described below can be created using DCC (Drive Control Chart) and are available as a

standard application "SINAMICS DCC load distribution" for SINAMICS S.

Torque coupling

A proportional-plus-integral-action controller is used to operate the master converter as a speed controller while a

simple proportional-action controller, i.e. without the integral-action component, is used on the slave converter. The

integral-action component of the master's speed controller is utilized as an additional torque in the slave. A drive-

specific torque pre-control can optionally be added to the torque value of the master. In this operating mode, the

torque setpoint is generated in part by the master and in part by the speed controller of the slave. The load balance

can be set with a load factor. Both drives have their own torque pre-control and both receive the same speed

setpoint.

Overload with torque limit

The torque setpoint of the master is added (preferably without pre-control) to the optional pre-control signal of the

slave. This signal is then applied as a positive torque limit and the speed setpoint is increased by an overload value

in order to ensure that the controller always operates at the upper torque limit unless the actual speed is higher than

the basic setpoint or is at the negative torque limit (if the master reduces the speed, i.e. the master torque setpoint is

negative). Should the connection between the two converters be interrupted for any reason, the slave cannot

accelerate to a speed higher than the speed defined by the overload factor.

A very precise model is required in order to calculate the correct torque values, particularly for the acceleration pre-

control. The master converter might otherwise become overloaded as a result of temporary load fluctuations or

acceleration.

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1.1.5 Power ratings of SINAMICS converters and inverters / Definition of the output power

SINAMICS converters produce an electrical three-phase system at their output, the power of which – taking into

consideration factor √3 – can be calculated from the output voltage and the output current, whereby any phase angle

can exist between output voltage and output current, depending on the load characteristics. Therefore electrical

output power, for which the converter’s output is designed, presents an apparent power as a result of the existing

phase angle. This apparent power can be calculated from the obtainable output voltage and the continuously

permissible thermal output current, which is the rated output current Irated. When it is taken into consideration that

SINAMICS converters in the vector control mode reach at the output almost the value of the incoming supply voltage

by using pulse-edge modulation, the apparent output power of the converter can be calculated using the following

formula:

Srated = √3 • Vline • Irated.

This apparent output power of the converter is a physically correct value, but it is not really suitable to allow a simple

correlation between the converter output power and the rated motor power as the apparent power of the converter

(given in kVA) and the mechanical shaft power (rated power) of the motor (given in kW) do not directly correspond

because current, power factor and efficiency of the motor are required.

A much simpler option for the coordination of the output power of the converter and the rated power of the motor is

the definition of an active output power for the converter, which is deduced from the mechanical shaft power (rated

power) of a typical three-phase asynchronous motor which can be operated by the converter.

Definition of the output power for SINAMICS converters and inverters

The active output power of a SINAMICS converter or inverter is defined as the mechanical shaft power (rated power)

of a typical, 6-pole, asynchronous motor, which can be operated by the converter or inverter at its rated point, without

overloading the converter or inverter. As 2 and 4-pole motors always have a better power factor and also equal or

lower rated currents, all 2, 4 and 6-pole motors are covered by the definition of the output power given above with

regard to the coordination of the power between converter and motor.

In the SINAMICS catalogs and operating instructions (equipment manuals), usually several values for the output

power of the converters or inverters are given:

· Output power on the basis of the base load current IL for low overloads

· Output power on the basis of the base load current IH for high overloads

Each value for the output power of converters and inverters applies to motors with rated voltages of 400 V, 500 V or

690 V as well as a rated frequency of 50 Hz. (The definition of the standard load duty cycles – low overload and high

overload – and the definition of the corresponding base load currents IL and IH is given in the section “Load duty

cycles”). It is particularly important with SINAMICS S120 and S150 units with the wide input voltage range of 500 V -

690 V 3AC that the values for the output power of these units are depending on the voltage. Therefore they are

significantly different for 500 V and 690 V.

The following example should clearly illustrate how the output power for a SINAMICS converter is determined:

Converter data:

Line supply voltage 380 V – 480 V

Rated output current 605 A

Base load current ILfor low overload 590 A

Base load current IHfor high overload 460 A

Rated outputs and rated currents of SIMOTICS TN series N-compact 1LA8

asynchronous motors listed in the catalog for operation with 400 V / 50 Hz:

Number of

poles

200 kW 250 kW 315 kW 355 kW 400kW

2- - 520 A 590 A 660 A

4- 430 A 540 A 610 A 690 A

6345 A 430 A 540 A - 690 A

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The output power of the above-mentioned converter for low overload, on the basis of the base load current IL at

400 V 3AC/50 Hz, is defined as the the rated power of the largest, 6-pole asynchronous motor for 400V/50 Hz

operation, the rated current of which does not exceed the base load current IL = 590 A of the converter. According to

this definition the converter has the output power of 315 kW at 400 V on the basis of IL.

The output power of the converter, which, as the rated power of the motor, is given in kW, offers the possibility of a

very simple and safe coordination between the power of the converter and the motor, without having to take into

consideration other details such as current, power factor and efficiency. If the output power of the converter is chosen

at least as big as the rated power of the motor, it is always safe to operate 2, 4 and 6-pole motors at full load with the

selected converter.

The example above also demonstrates, however, that it is quite possible in individual cases to operate motors with a

small number of poles (2 to 4), whose rated power exceeds the output power of the converter, continuously at their

nominal working point without overloading the converter. In the chosen example above, this applies to the 2-pole

motor with a rated power of 355 kW.

Therefore on the one hand, the output power of the converter offers and extremely simple and safe way of

coordinating the power of a converter and a motor. On the other hand, however, this coordination can lead to an

overdimensioning of the converter in combination with motors with a low number of poles. If you want to achieve

optimum coordination between the converter and the motor, you must choose the more complicated method involving

the currents.

Note:

If the converters and inverters in this engineering manual are characterized according to their output power, which is

true in many tables in this document, then the output power is always referred to the base load current IL, to the line

frequency 50 Hz and to line supply voltage 400 V or 500 V or 690 V.

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1.2 Supply systems and supply system types

1.2.1 General

The low-voltage products in the SINAMICS series with line supply voltages of ≤ 690 V are normally connected to

industrial supply systems that are supplied from the medium-voltage distribution system via transformers. In rare

cases, however, these devices may be directly connected to the public low-voltage supply systems or to separate

supply systems, such as those supplied by diesel-electric generators.

IEC 60364-1 stipulates that supply networks are classified as either TN, TT or IT systems depending on the type of

arrangement of the exposed-conductive parts and the grounding method. The classifications and letters are

explained in brief below.

First letter: Relationship of the supply system to ground:

T = Direct connection of one point to ground.

I = All live parts isolated from ground, or one point connected to ground through an impedance.

Second letter: Relationship of the exposed-conductive parts (enclosures) of the installation to ground:

T = Direct electrical connection of the exposed-conductive parts (enclosures) to ground, independent of

whether one point of the supply system is already grounded.

N = Direct electrical connection of the exposed-conductive parts (enclosures) to the grounded point of the

supply system (the grounded point of the supply system is generally the star point in three-phase

systems, or one of the three phases if the system has no star point).

In TN systems, one point is directly grounded and the exposed-conductive parts (enclosures) of the electrical

installation are connected to the same point via a protective conductor (protective earth PE).

Example of a TN supply system with grounded starpoint

In TT systems, one point is directly grounded and the exposed-conductive parts (enclosures) of the installation are

connected to ground electrodes which are electrically independent of the ground electrodes of the supply system.

Example of a TT supply system with grounded starpoint

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In IT systems, all live parts are isolated from ground, or one point is connected to ground through a high-value

impedance. All the exposed-conductive parts (enclosures) in the electrical installation are connected to an

independent ground electrode, either separately or in a group.

Example of an IT supply system

SINAMICS units are designed for connection to three-phase AC supply systems in accordance with overvoltage

category III as defined by IEC 60664-1 / IEC 61800-5-1. They can be connected either to grounded TN or TT

systems or to non-grounded IT systems. (Exception: TN or TT systems with a line voltage > 3AC 600 V and

grounded phase conductor. In this case, the customer must take measures to limit surge voltages to overvoltage

category II according to IEC 60664-1 / IEC 61800-5-1).

Notes about grounded TN or TT systems

In grounded TN or TT systems, the supply system is directly grounded at one point. The system can be grounded at

any point, but two grounding points are normally preferred in practice:

· Neutral of the supply system (with a star-connected system)

· Phase conductor of the supply system

Directly grounded neutral

The neutral of the supply system (transformer, generator) is directly grounded. The voltage of the three phase

conductors relative to ground is then symmetrical and the insulation of the converter and motor to ground is evenly

stressed in all three phases on a relatively low level.

The RFI suppression filters for the second environment (Category C3 according to EMC product standard EN 61800-

3) that are integrated as standard in SINAMICS units and the optionally available RFI suppression filters for the first

environment (Category C2 according to EMC product standard EN 61800-3) are designed for use in supply systems

with directly grounded neutral and may only be used in systems of this kind.

Directly grounded phase conductor

One phase conductor of the supply system (transformer, generator) is directly grounded. The voltage of the three

phase conductors to ground is then asymmetrical and the stress on the insulation of the two non-grounded phase

conductors to ground is increased by a factor of 1.73. For this reason, the SINAMICS units described in this

engineering manual may be connected to supply systems with directly grounded phase conductor only when the

supply voltage is ≤ 600 V 3AC.

The RFI suppression filters for the second environment (Category C3 according to EMC product standard EN 61800-

3) that are integrated as standard in SINAMICS units must be disconnected from ground by removal of a metal clip

from the filter and the optionally available RFI suppression filters for the first environment (Category C2 according to

EMC product standard EN 61800-3) must not be installed. The SINAMICS units then only conform to Category C4 as

defined in EMC product standard EN 61800-3.

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Notes about non-grounded IT supply systems

In non-grounded IT systems, all live parts are isolated from ground, or one point is connected to ground through a

high-value impedance.

In this engineering manual, the term "non-grounded IT system" generally refers to a system in which all live parts are

isolated from ground. All further statements relating to non-grounded IT systems refer to a system of this kind.

Supply systems in which one point is grounded via an impedance are not discussed any further because, on the one

hand, they are very rare and on the other, it is impossible to make generally valid statements about them since their

characteristics vary widely depending on the type and magnitude of the grounding impedance. Use of such systems

must be clarified on a case-by-case basis.

1.2.2 Connection of converters to the supply system and protection of converters

The devices are equipped with means of connecting the three phase conductors (L1, L2, L3) and the protective

conductor (PE) to ground. No connection for a separate neutral conductor (N) is provided, nor is one necessary as

the converters place a symmetrical load on the three-phase system and the neutral is not therefore loaded.

If a single-phase AC voltage, e.g. 230 V, is required to supply auxiliaries or the fan, this is supplied internally via

single-phase control transformers that are connected between two phase conductors. The control transformers for

the auxiliaries of the cabinet units are either installed as standard or available to order as options depending on the

unit type. The single-phase AC voltage can be supplied alternatively from an external source at the terminals

provided as described in the section "Behavior of SINAMICS converters during supply voltage variations and dips".

Line-side protective devices must be provided for Chassis and cabinet units in order to protect the devices and their

mains supply conductors against short circuits and ground faults.

The mains supply conductor can be protected by appropriate line fuses, which should be arranged as close as

possible to the mains connection point, in other words, at the line-side end of the conductor and not at the converter

input end. This applies especially in the case of long supply conductors. Suitable line fuses of type 3NA can be found

in Catalogs D11 and D21.3.

If the fuses arranged at the mains connection point are to protect the mains supply conductor and act as

semiconductor protection for the thyristors or diodes in the rectifiers of SINAMICS G130 and G150 converters and for

the thryristors and diodes in the S120 Basic Infeeds, dual-function fuses of type 3NE1 must be used instead of line

fuses of type 3NA. Fuses of type 3NE1 can also be found in Catalogs D11 and D21.3. In systems using S120 Smart

Infeeds and S120 Active Infeeds and in S150 converters equipped with IGBT rectifiers, semiconductor protection

cannot be provided by fuses of any type due to the low I2t values of the IGBT chips. However, 3NE1 dual-function

fuses provide better limitation of the damage after a serious fault than line fuses of type 3NA.

Cabinet units of types SINAMICS G150 and S150 as well as S120 Cabinet Modules can be protected by optional line

fuses or, with higher current ratings, by optional circuit breakers installed at the line side in the devices themselves.

The type 3NE1 fuses used for this purpose are dual-function fuses. If these optional line fuses or circuit breakers are

used as device protection, additional fuse protection in the form of a 3NA line fuse must be provided for the mains

supply conductor at the mains connection point, particularly in cases where very long mains supply conductors are

used.

Notes about line-side fusing:

Short circuits which occur upcircuit of the rectifier have no effect on the thyristors or diodes. Dual-function fuses

cannot therefore offer any particular advantages in this situation.

In the event of a short circuit in the rectifier itself, i.e. as the result of a defective thyristor, the rectifier is defective

anyway which means that there is no particular advantage of using dual-function fuses.

However, when a short circuit occurs downcircuit of the rectifier, i.e. in the DC link or the inverter, e.g. due to a

defective IGBT, dual-function fuses are recommended as a means of protecting the line-side thyristors or diodes. It is

simpler, quicker and cheaper to repair the unit because fewer defective components need to be replaced. Particularly

in the case of larger devices with separate power blocks for rectifier and inverter, the use of dual-function fuses can in

general obviate the need to replace the rectifier power block.

The following general recommendation therefore applies:

Since the statistical probabilities of failure of components dictate that an inverter fault is more probable than a rectifier

fault, the use of dual-function fuses of type 3NE1 to protect the thyristors or diodes in the rectifier is strongly

recommended. Owing to their high-speed tripping characteristic, these dual-function fuses also limit the damage in

the defective power block more effectively than line fuses of type 3NA.

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1.2.3 Short Circuit Current Rating (SCCR according to UL)

In the USA a rating plate must be attached to the switchgear (referred to as Industrial Control Panel ICP) which

indicates the "short-circuit current rating" (overall panel SCCR) of the installation. Specification of the Short Circuit

Current Rating SCCR became essential when the National Electrical Code NEC 2005 came into force. The SCCR is

determined on the basis of UL508A Supplement SB4.

I×× 22

In order to ensure that the switchgear can withstand a short circuit in the main circuit without sustaining serious

damage, e.g. mechanical defects caused by excess current or defects resulting from overheating, the maximum

possible short-circuit current may not exceed the SCCR value of the installation.

The data of the transformer T2, which supplies the switchgear directly, generally provide an adequate basis for

making a rough estimation of the maximum possible short-circuit current at the installation site. As a general rule, the

high-voltage and medium-voltage levels have a minor influence and can therefore be ignored. Based on the rated

current Irated and the relative short-circuit voltage vk (per unit impedance) of the transformer T2, the short-circuit

current Ik is calculated according to the following equation:

Ik = Irated / vk.

Example:

A transformer with a voltage of 460 V 3AC on the low-voltage side and a rated power of 1 MVA has a rated current of

1255 A. The relative short-circuit voltage vk (per unit impedance) of the transformer is 6 % or 0.06. The maximum

possible (continuous) short-circuit current directly at the output terminals of the transformer, i.e. on the low-voltage

busbar, is thus calculated to be Ik = 1255 A / 0.06 ≈ 21 kA.

In order to calculate the short-circuit current exactly, it is necessary to know the short-circuit power of the high-voltage

grid supply and the effective impedance of transformers T1 and T2, plus the effective impedance of the supply cable.

The maximum peak short-circuit current ip is reached when the short circuit occurs at the voltage zero crossing.

Methods for the precise calculation of short-circuit currents are given, for example, in IEC 60909-0.

Since the maximum possible short-circuit current obtained from the exact calculation method when all effective

impedance is taken into account is lower than the value estimated from the data of the supply transformer T2, the

estimation method generally yields a safer result. This applies particularly in the case of units which are not

connected directly to busbars but over long cables directly to the transformer.

In meshed systems supplied by multiple transformers connected in parallel, the process of calculating short-circuit

current Ik or peak short-circuit current ip is more complex.

The short-circuit current strength of the entire switchgear installation (overall panel SCCR) as specified on its rating

plate is determined by the component in the main circuit with the lowest SCCR value.

Standard SCCR values for electrical equipment are specified in UL 508A Supplement SB4.2 (September 2005).

These can be used to calculate the overall panel SCCR.

The SCCR values of the approved SINAMICS G130 converter Chassis units and the approved modular SINAMICS

S120 built-in units in Chassis format are higher than the listed standard SCCR values. These higher SCCR values

are valid only in combination with the fuses or circuit breakers stated in the catalogs and operating instructions.

Fuses or circuit breakers can be replaced by comparable types only on the condition that the peak let-through current

and the breaking I2t value of the replacement type is not higher than those of the recommended type.

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The following table lists the standard SCCR values for electric drives ("Motor Controllers") according to UL 508A, as

well as the SCCR values of the approved SINAMICS G130 converter Chassis units and the approved modular

SINAMICS S120 built-in units in Chassis format.

Output power of the electric drive

“Motor Controller”

Standard SCCR values

according to UL 508A

SCCR values of the UL-approved Built-in units

SINAMICS G130 and S120 in Chassis format

51 – 200 hp (38 – 149 kW) 10 kA 65 kA

201 – 400 hp (150 – 298 kW) 18 kA 65 kA

401 – 600 hp (299 – 447 kW) 30 kA 65 kA

601 – 900 hp (448 – 671 kW) 42 kA 84 kA

901 – 1500 hp (672 – 1193 kW) 85 kA 170 kA

Standard SCCR values according to UL 508A and SCCR values of the approved SINAMICS G130 and S120 Chassis units

1.2.4 Maximum short-circuit currents (SCCR according to IEC) and minimum short-circuit currents

The following tables specify the maximum permissible line-side short-circuit currents and the recommended minimum

line-side short-circuit currents for SINAMICS G130 converter Chassis units, SINAMICS G150 and S150 converter

cabinet units and for the SINAMICS S120 Infeeds in Chassis and Cabinet Modules format.

The maximum permissible short-circuit currents are the line-side short-circuit currents for which the units are

designed. Provided that the maximum permissible short-circuit currents are not exceeded, the equipment will not

develop any defects as a result of excess current or overheating in the event of a short circuit. This is why it is

important to ensure that the supply systems to which the SINAMICS units are connected are not capable of supplying

higher short-circuit currents than the maximum permissible short-circuit currents of the connected SINAMICS

converters. Since the incoming busbars as well as the fuse switch disconnectors and circuit breakers which might

also be installed each have different short-circuit current limits, the weakest component in each case determines the

permissible short-circuit current for all other components. In consequence, the values stated in the tables for the

cabinet units are dependent on whether the units have no line-side fuse elements or whether they are equipped with

the main switches including 3NE1 fuses or 3WL circuit breakers that are available as option L26.

The recommended minimum short-circuit currents are the minimum line-side short-circuit currents which should

be produced at the point of common coupling of the SINAMICS units by the supply system in the event of a short

circuit in order to ensure tripping of the line-side fuses of type 3NE1 within approximately half a line period and of the

circuit breakers of type 3WL within around 100 ms (types 3NE1 and 3WL are recommended in catalogs D 11 and

D 21.3). In the next column of the table, the associated minimum relative short-circuit power RSCmin at the point of

common coupling is specified - this is defined as the ratio between the minimum required short-circuit power SK Line at

the point of common coupling and the rated apparent power (fundamental apparent power) Sconverter of the connected

converter (or the connected Infeed). The last column in the table specifies the maximum permissible relative short-

circuit voltage vkmax of the supply system (per unit impedance) which corresponds to the minimum relative short-

circuit power RSCmin. Irrespective of the value for the minimum relative short-circuit power RSCmin, the maximum

relative short-circuit voltage vkmax of the supply system (per unit impedance) should not be greater than ≈ 10 % in

order to limit the harmonic effects on the supply system to an acceptable level.

Note:

The minimum short-circuit current specifications are the values recommended in order to ensure rapid tripping of the

line-side fuses of type 3NE1 within approximately half a line period. If a particular system configuration is such that

the short-circuit currents produced by the system are slightly lower than the recommended values, then the fuses will

take longer to respond. The total breaking I2t value therefore increases and the level of protection for the thyristors

and diodes in the rectifiers might be reduced as a result. The fuses are nevertheless still guaranteed to trip provided

that the minimum short-circuit currents correspond to around 80 to 90% of the recommended values.

Fundamental Principles and System Description

Engineering Information

SINAMICS Engineering Manual – July 2017

Ó Siemens AG 41/554

Output

power

SINAMICS

G130

at 400V /

500V / 690V

[ kW ]

Frame

size

[ - ]

Rated

input current

[ A ]

Maximum

short-circuit current

[ kA ]

Minimum

short-circuit

current

[ kA ]

Min. relative

short-circuit

power

RSCmin

[ - ]

Max. relative

short-circuit

voltage

vk max

[ % ]

SINAMICS G130 / 380 V – 480 V 3AC

110 FX 229 651 3.0 13.1 7.6

132 FX 284 651 3.6 12.7 7.9

160 GX 338 651 4.4 13.0 7.7

200 GX 395 651 4.4 11.1 9.0

250 GX 509 651 8.0 15.7 6.4

315 HX 629 65110.0 15.9 6.3

400 HX 775 65110.5 13.6 7.4

450 HX 873 84116.0 18.3 5.5

560 JX 1024 84118.4 18.0 5.6

SINAMICS G130 / 500 V – 600 V 3AC

110 GX 191 651 2.4 12.6 8.0

132 GX 224 651 3.0 13.4 7.5

160 GX 270 651 3.6 13.3 7.5

200 GX 343 651 5.2 15.2 6.6

250 HX 426 651 5.2 12.2 8.2

315 HX 483 651 6.2 12.8 7.8

400 HX 598 651 8.4 14.0 7.1

500 JX 764 84110.5 13.7 7.3

560 JX 842 84110.4 12.4 8.1

SINAMICS G130 / 660 V – 690 V 3AC

75 FX 93 651 1.1 11.8 8.5

90 FX 109 651 1.1 10.1 10.0

110 FX 131 651 1.2 9.2 11.0

132 FX 164 651 1.6 9.8 10.2

160 GX 191 651 2.4 12.6 8.0

200 GX 224 651 3.0 13.4 7.5

250 GX 270 651 3.6 13.3 7.5

315 GX 343 651 5.2 15.2 6.6

400 HX 426 651 5.2 12.2 8.2

450 HX 483 651 6.2 12.8 7.8

560 HX 598 651 8.4 14.0 7.1

710 JX 764 84110.5 13.7 7.3

800 JX 842 84110.4 12.4 8.1

1) These values apply to G130 Chassis units and do not take in account line-side fuse switch disconnectors or circuit breakers

SINAMICS G130: Maximum and minimum line-side short-circuit currents

Fundamental Principles and System Description

Engineering Information

SINAMICS Engineering Manual – July 2017

Ó Siemens AG

42/554

Output

power

SINAMICS

G150

at 400V /

500V / 690V

[ kW ]

Frame

size

[ - ]

Rated

input current

[ A ]

Maximum

short-circuit current

[ kA ]

Minimum

short-circuit

current

[ kA ]

Min. relative

short-circuit

power

RSCmin

[ - ]

Max. relative

short-circuit

voltage

vk max

[ % ]

SINAMICS G150 / 380 V – 480 V 3AC

110 F 229 651 / 652 3.0 13.1 7.6

132 F 284 651 / 652 3.6 12.7 7.9

160 G 338 651 / 652 4.4 13.0 7.7

200 G 395 651 / 502 4.4 11.1 9.0

250 G 509 651 / 502 8.0 15.7 6.4

315 H 629 651 / 50210.0 15.9 6.3

400 H 775 651 / 50210.5 13.6 7.4

450 H 873 841 / 55316.01 / 1,8318.31 / 2.13 5.51 / ≈ 103

560 J 1024 841 / 55318.41 / 2.0318.01 / 2.03 5.61 / ≈ 103

630 2 x H 1174 2 x 651 / 2 x 5022 x 10.0 17.0 5.9

710 2 x H 1444 2 x 651 / 2 x 5022 x 10.5 14.5 6.9

900 2 x H 1624 2 x 55 2 x 1.8 2.1 ≈ 10

SINAMICS G150 / 500 V – 600 V 3AC

110 G 191 651 / 652 2.4 12.6 8.0

132 G 224 651 / 652 3.0 13.4 7.5

160 G 270 651 / 652 3.6 13.3 7.5

200 G 343 651 / 652 5.2 15.2 6.6

250 H 426 651 / 502 5.2 12.2 8.2

315 H 483 651 / 502 6.2 12.8 7.8

400 H 598 651 / 502 8.4 14.0 7.1

500 J 764 841 / 50210.5 13.7 7.3

560 J 842 841 / 84310.41 / 1,8312.41 / 2.13 8.11 / ≈ 103

630 2 x H 904 2 x 651 / 2 x 502 2 x 6.2 13.7 7.3

710 2 x H 1116 2 x 651 / 2 x 502 2 x 8.4 15.1 6.6

1000 2 x J 1424 2 x 841 / 2 x 5022 x 10.5 14.7 6.8

SINAMICS G150 / 660 V – 690 V 3AC

75 F 93 651 / 652 1.1 11.8 8.5

90 F 109 651 / 652 1.1 10.1 10.0

110 F 131 651 / 652 1.2 9.2 11.0

132 F 164 651 / 652 1.6 9.8 10.2

160 G 191 651 / 652 2.4 12.6 8.0

200 G 224 651 / 652 3.0 13.4 7.5

250 G 270 651 / 652 3.6 13.3 7.5

315 G 343 651 / 652 5.2 15.2 6.6

400 H 426 651 / 502 5.2 12.2 8.2

450 H 483 651 / 502 6.2 12.8 7.8

560 H 598 651 / 502 8.4 14.0 7.1

710 J 764 841 / 50210.5 13.7 7.3

800 J 842 841 / 84310.41 / 2.0312.41 / 2.43 8.11 / ≈ 103

1000 2 x H 1116 2 x 651 / 2 x 502 2 x 8.4 15.1 6.6

1350 2 x J 1424 2 x 841 / 2 x 5022 x 10.5 14.8 6.8

1500 2 x J 1568 2 x 84 2 x 1.8 2.3 ≈ 10

1750 2 x (GB+JX) 1800 2 x 85 2 x 1.8 2.0 ≈ 10

1950 2 x (GB+JX) 2030 2 x 85 2 x 2.0 2.0 ≈ 10

2150 2 x (GB+JX) 2245 2 x 85 2 x 2.3 2.0 ≈ 10

2400 2 x(GD+JX) 2510 2 x 85 2 x 2.5 2.0 ≈ 10

2700 2 x(GD+JX) 2865 2 x 85 2 x 2.5 1.8 ≈ 10

1) These values apply to cabinet units without option L26, i.e. without fuse switch disconnectors including 3NE1 fuses or without circuit breakers

2) These values apply to cabinet units with option L26 = fuse switch disconnectors including 3NE1 fuses

3) These values apply to cabinet units with option L26 = circuit breakers

SINAMICS G150: Maximum and minimum line-side short-circuit currents

Fundamental Principles and System Description

Engineering Information

SINAMICS Engineering Manual – July 2017

Ó Siemens AG 43/554

Output

power

SINAMICS

S150

at 400 V

or 690 V

[ kW ]

Frame

size

[ - ]

Rated

input current

[ A ]

Maximum

short-circuit current

[ kA ]

Minimum

short-circuit

current

[ kA ]

Min. relative

short-circuit

power

RSCmin

[ - ]

Max. relative

short-circuit

voltage

vk max

[ % ]

SINAMICS S150 / 380 V – 480 V 3AC

110 F 197 651 / 652 3.0 15.2 6.6

132 F 242 651 / 652 3.0 12.4 8.1

160 G 286 651 / 652 4.5 15.7 6.4

200 G 349 651 / 502 4.5 12.9 7.8

250 G 447 651 / 502 8.0 17.9 5.6

315 H 549 651 / 50212.0 21.8 4.6

400 H 674 651 / 50215.0 22.2 4.5

450 H 759 55 2.0 2.6 ≈ 10

560 J 888 55 2.5 2.8 ≈ 10

710 J 1133 55 3.2 2.8 ≈ 10

800 J 1262 55 3.2 2.5 ≈ 10

SINAMICS S150 / 500 V – 690 V 3AC

75 F 86 651 / 652 1.0 11.6 8.6

90 F 99 651 / 652 1.0 10.1 9.9

110 F 117 651 / 652 1.3 11.1 9.0

132 F 144 651 / 652 1.8 12.5 8.0

160 G 166 651 / 652 2.5 15.1 6.6

200 G 202 651 / 652 3.0 14.8 6.7

250 G 242 651 / 652 3.0 12.4 8.1

315 G 304 651 / 652 4.5 14.8 6.8

400 H 375 651 / 502 4.5 12.0 8.3

450 H 424 651 / 502 7.0 16.5 6.1

560 H 522 651 / 502 9.0 17.2 5.8

710 J 665 851 / 50215.0 22.6 4.4

800 J 732 85 2.0 2.7 ≈ 10

900 J 821 85 2.0 2.4 ≈ 10

1000 J 923 85 2.5 2.7 ≈ 10

1200 J 1142 85 3.2 2.8 ≈ 10

1) These values apply to cabinet units without option L26, i.e. without fuse switch disconnectors including 3NE1 fuses

2) These values apply to cabinet units with option L26, i.e. with fuse switch disconnectors including 3NE1 fuses

SINAMICS S150: Maximum and minimum line-side short-circuit currents

Fundamental Principles and System Description

Engineering Information

SINAMICS Engineering Manual – July 2017

Ó Siemens AG

44/554

Output

power

SINAMICS

S120 BLM

at 400 V

or 690 V

[ kW ]

Frame

size

[ - ]

Rated

input current

[ A ]

Maximum

short-circuit current

[ kA ]

Minimum

short-circuit

current

[ kA ]

Min. relative

short-circuit

power

RSCmin

[ - ]

Max. relative

short-circuit

voltage

vk max

[ % ]

SINAMICS S120 BLM / 380 V – 480 V 3AC

200 FB 365 651 / 502 4.4 12.1 8.3

250 FB 460 651 / 502 5.2 11.3 8.9

360 FBL 610 651 / 502 8.8 14.4 6.9

400 FB 710 651 / 50210.0 14.1 7.1

560 GB 1010 841 / 84312.41 / 2.5312.31 / 2.538.11 / ≈ 103

600 FBL 1000 841 / 84312.41 / 2.5312.41 / 2.538.11 / ≈ 103

710 GB 1265 1701 / 100318.41 / 3.2314.51 / 2.536.91 / ≈ 103

830 GBL 1420 1701 / 100320.01 / 3.2314.11 / 2.337.11 / ≈ 103

900 GD 1630 1701 / 100318.61 / 4.0311.41 / 2.538.81 / ≈ 103

SINAMICS S120 BLM / 500 V – 690 V 3AC

250 FB 260 651 / 652 3.0 11.5 8.7

355 FB 375 651 / 652 4.4 11.7 8.5

355 FBL 340 651 / 652 4.4 12.9 7.7

560 FB 575 651 / 502 8.0 13.9 7.2

630 FBL 600 651 / 502 7.2 12.0 8.3

900 GB 925 841 / 84310.41 / 2.0311.21 / 2.238.91 / ≈ 103

1100 GB 1180 1701 / 85316.01 / 2.5313.61 / 2.137.41 / ≈ 103

1100 GBL 1070 1701 / 85316.81 / 2.5315.71 / 2.336.41 / ≈ 103

1370 GBL 1350 1701 / 85316.81 / 3.2312.41 / 2.438.01 / ≈ 103

1500 GD 1580 1701 / 85318.61 / 3.2311.81 / 2.038.51 / ≈ 103

1) These values apply to BLMs in Chassis format and do not take in account line-side fuse switch disconnectors or circuit breakers

2) These values apply to BLMs in Cabinet Modules format with fuse switch disconnectors including 3NE1 fuses in the LCM

3) These values apply to BLMs in Cabinet Modules format with circuit breaker in the LCM

SINAMICS S120 BLM: Maximum and minimum line-side short-circuit currents

Output

power

SINAMICS

S120 SLM

at 400 V

or 690 V

[ kW ]

Frame

size

[ - ]

Rated

input current

[ A ]

Maximum

short-circuit current

[ kA ]

Minimum

short-circuit

current

[ kA ]

Min. relative

short-circuit

power

RSCmin

[ - ]

Max. relative

short-circuit

voltage

vk max

[ % ]

SINAMICS S120 SLM / 380 V – 480 V 3AC

250 GX 463 651 / 502 6.2 13.4 7.5

355 GX 614 651 / 502 9.2 15.0 6.7

500 HX 883 841 / 84310.41 / 2.0311.81 / 2.338.51 / ≈ 103

630 JX 1093 841 / 84316.01 / 2.5314.61 / 2.336.81 / ≈ 103

800 JX 1430 1701 / 100321.01 / 3.2314.71 / 2.236.81 / ≈ 103

SINAMICS S120 SLM / 500 V – 690 V 3AC

450 GX 463 651 / 502 6.2 13.4 7.5

710 HX 757 841 / 50210.5 13.9 7.2

1000 JX 1009 1701 / 85312.41 / 2.5312.31 / 2.538.11 / ≈ 103

1400 JX 1430 1701 / 85321.01 / 3.2314.71 / 2.236.81 / ≈ 103

1) These values apply to SLMs in Chassis format and do not take in account line-side fuse switch disconnectors or circuit breakers

2) These values apply to SLMs in Cabinet Modules format with fuse switch disconnectors including 3NE1 fuses in the LCM

3) These values apply to SLMs in Cabinet Modules format with circuit breaker in the LCM

SINAMICS S120 SLM: Maximum and minimum line-side short-circuit currents

Fundamental Principles and System Description

Engineering Information

SINAMICS Engineering Manual – July 2017

Ó Siemens AG 45/554

Output

power

SINAMICS

S120 ALM

at 400 V

or 690 V

[ kW ]

Frame

size

[ - ]

Rated

input current

[ A ]

Maximum

short-circuit current

[ kA ]

Minimum

short-circuit

current

[ kA ]

Min. relative

short-circuit

power

RSCmin

[ - ]

Max. relative

short-circuit

voltage

vk max

[ % ]

SINAMICS S120 ALM + AIM / 380 V – 480 V 3AC

132 FX 210 651 / 652 3.0 14.3 7.0

160 FX 260 651 / 652 3.6 13.8 7.2

235 GX 380 651 / 502 5.2 13.7 7.3

300 GX 490 651 / 502 8.0 16.3 6.1

300 GXL 490 651 8.0 16.3 6.1

380 HX 605 651 / 502 9.2 15.2 6.6

380 HXL 605 651 / 502 9.2 15.2 6.6

450 HX 745 841 8.8 11.8 8.5

500 HX 840 841 / 84310.41 / 2.0312.41 / 2.438.11 / ≈ 103

500 HXL 840 841 / 84310.41 / 2.0312.41 / 2.438.11 / ≈ 103

630 JX 985 841 / 84316.01 / 2.0316.21 / 2.036.21 / ≈ 103

630 JXL 985 841 / 84316.01 / 2.0316.21 / 2.036.21 / ≈ 103

800 JX 1260 170121.0 16.7 6.0

900 JX 1405 1701 / 100321.01 / 3.2315.01 / 2.336.71 / ≈ 103

900 JXL 1405 1701 / 100321.01 / 3.2315.01 / 2.336.71 / ≈ 103

SINAMICS S120 ALM + AIM / 500 V – 690 V 3AC

630 HX 575 651 / 502 8.4 14.6 6.8

630 HXL 575 651 8.4 14.6 6.8

800 JX 735 841 / 50210.5 14.3 7.0

800 HXL 735 841 / 50210.5 14.3 7.0

900 HXL 810 841 / 84316.01 / 2.0319.81 / 2.535.11 / ≈ 103

1100 JX 1025 1701 / 85316.01 / 2.5315.61 / 2.436.41 / ≈ 103

1100 JXL 1025 1701 / 85316.01 / 2.5315.61 / 2.436.41 / ≈ 103

1400 JX 1270 1701 / 85320.01 / 3.2315.71 / 2.536.41 / ≈ 103

1400 JXL 1270 1701 / 85320.01 / 3.2315.71 / 2.536.41 / ≈ 103

1700 JXL 1560 2001 / 85324.01 / 3.2315.41 / 2.136.51 / ≈ 103

1) These values apply to ALM+AIM combinations in Chassis format and do not take in account line-side fuse switch disconnectors or circuit breakers

2) These values apply to ALM+AIM combinations in Cabinet Modules format with fuse switch disconnectors including 3NE1 fuses in the LCM

3) These values apply to ALM+AIM combinations in Cabinet Modules format with circuit breaker in the LCM

SINAMICS S120 ALM+AIM: Maximum and minimum line-side short-circuit currents

1.2.5 Connection of converters to grounded systems (TN or TT)

On SINAMICS units connected to grounded TN or TT systems, it is basically possible to connect a ground fault

monitor capable of early detection of high-impedance ground faults (universal-AC/DC-sensitive differential current

monitor or Residual Current Monitor RCM) to the converter input. However, this ground fault monitor is relatively

complicated to install owing to the need for a summation current transformer in the mains feeder cable. Furthermore,

the response threshold of the monitor must be adjusted according to the relevant plant conditions. This means, for

example, on drives with long shielded motor cables in the power range of the SINAMICS converters described in this

engineering manual, the response thresholds of 30 mA or 300 m which would be required to ensure personnel safety

and fire protection are not technically feasible (see also section "Line filters", subsection "Magnitude of leakage or

interference currents"). For this reason, it is not normal practice to use a ground fault monitor in the power range of

the SINAMICS converters described in this manual. However, as described above, suitable protection must be

provided on the line side to ensure that the substantial ground fault current caused by a low-impedance ground fault

or short circuit in the device is promptly interrupted.

Fundamental Principles and System Description

Engineering Information

SINAMICS Engineering Manual – July 2017

Ó Siemens AG

46/554

Ground faults at the output side in the motor cable or in the motor itself can be detected by the electronic ground fault

monitor implemented in the inverter. The response threshold of this monitor can be parameterized in the firmware to

values higher than about 10 % of the rated output current.

SINAMICS converters for operation in grounded TN and TT systems with grounded neutral are equipped as standard

with RFI suppression filters for the "second" environment (Category C3 according to EMC product standard EN

61800-3). This applies to SINAMICS G150 and S150 cabinets, to SINAMICS G130 Chassis and to the Infeeds (Basic

Infeeds, Smart Infeeds and Active Infeeds) of the S120 modular system (Chassis and Cabinet Modules). For more

information about RFI suppression, please refer to the section "Line filters" or to the chapter "EMC Installation

Guideline".

1.2.6 Connection of converters to non-grounded systems (IT)

SINAMICS converters can also be connected to and operated on non-grounded IT supply systems. The advantage of

IT systems as compared to grounded supply systems is that no ground-fault current can flow when a ground fault

occurs and operation can therefore be maintained. The system does not shut down on faults until a second ground

fault occurs. This advantage means that IT supply systems are widely used in areas where fault tripping needs to be

reduced to a minimum due to the processes being carried out (e.g. in the chemical, steel, and paper industry).

Voltage conditions in normal operation and in the event of a ground fault

Voltage conditions in the IT supply system, both in normal operation and in the event of a ground fault, are described

and explained in brief below.

In normal operation, the voltages of the three line phases (phase to ground) VLine-PE in the IT system are connected to

ground by the capacitances of the transformer winding and the mains supply conductors. This symmetrical,

capacitive ground connection ensures that the voltage conditions in the IT supply system relative to ground potential

are very similar to those in a TN or TT supply system. In converters with line-commutated, unregulated rectifiers, the

positive pole of the DC link (+DC) tracks the positive peaks of the line voltage and the negative pole of the DC link

(-DC) the negative peaks. The DC link voltage VDC is thus symmetrical relative to ground potential PE, with the

positive pole +DC higher than ground potential PE by a factor of VDC/2 and the negative pole -DC lower than ground

potential PE by a factor of VDC/2. Each phase of the inverter output is connected alternately with the positive and

negative poles of the DC link by the switching of the IGBTs. Each inverter phase is thus connected alternately to

potential +VDC/2 and potential -VDC/2. Due to reflections caused by the use of long motor cables or transient

phenomena which develop when motor reactors are installed the peak voltage at the motor terminals (phase to

ground) VMotor-PE can reach significantly higher values than the voltage (phase to ground) at the inverter output VINV-

PE. In the worst-case scenario, the following can occur:

VMotor-PE = 2 • VINV-PE = VDC.

The voltage conditions in the IT supply system during normal operation are graphically represented in the diagram

below.

IT supply

system

Rectifier

and

DC link

Inverter Motor

+DC

-DC

Line voltage,

(phase to ground)

DC voltage,

(phase to ground)

Inverter output voltage,

(phase to ground)

Motor voltage,

(phase to ground)

Voltage conditions in the IT system during normal operation

In the event of a ground fault affecting one phase of the inverter output, the ground potential PE of the affected phase

is connected alternately to the positive pole +DC and the negative pole -DC of the DC link as a result of the switching

of the IGBTs. As a result, the positive and negative poles are at ground potential PE in alternating cycles. The

potential of the DC link pole which is not currently at ground potential is either higher or lower than ground potential

PE by a factor corresponding to the DC link voltage VDC. The two inverter output phases that are not affected by the

ground fault are connected alternately with the positive and negative poles of the DC link by the switching of the

IGBTs. Each of these two inverter phases thus alternates between potential +VDC and potential -VDC. Due to

reflections caused by the use of long motor cables or transient phenomena which develop when motor reactors are

installed the peak voltage at the motor terminals (phase to ground) VMotor PE can reach significantly higher values than

the voltage (phase to ground) at the inverter output VINV-PE. In the worst-case scenario, the following can occur:

VMotor-PE = 2 • VINV-PE = 2 • VDC.

Fundamental Principles and System Description

Engineering Information

SINAMICS Engineering Manual – July 2017

Ó Siemens AG 47/554

However, the step changes in the potentials +DC and -DC in the DC link caused by the ground fault at the inverter

output and switching of the IGBTs, do not only increase the voltage load in the converter and the motor winding. They

also have an impact on the line voltage itself because, in an IT supply system, this is grounded only through

capacitances. The step changes in potential in the DC link are thus superimposed on the line voltage (phase to

ground) VLine-PE with the result that the voltage load on the line side also increases significantly.

By comparison with normal operating conditions in the IT supply system, the line voltage (phase to ground) increases

significantly and loses its sinusoidal shape when a ground fault develops. The voltage load in the DC link and in the

inverter section of the converter (phase to ground) increases to twice its normal value and also the voltage load in the

motor winding (phase to ground) reaches twice its nominal value.

The voltage conditions in the IT supply system in the event of a ground fault are graphically represented in the

diagram below.

Line voltage,

(phase to ground)

DC voltage,

(phase to ground)

Inverter output voltage,

(phase to ground)

Motor voltage,

(phase to ground)

Voltage conditions in the IT system in the event of a ground fault

Insulation monitoring

In IT systems, a ground fault must be detected and eliminated as quickly as possible. This is necessary for two

reasons. First, a second ground fault occurring will lead to a short-circuit current and therefore to a fault tripping and,

in turn, to an interruption in operation. Second, a phase conductor or one pole of the DC link in the converter is

grounded when a ground fault occurs, which leads (as described above) to a 2 times higher operational voltage load

on the converter and motor insulation caused by the conductors that are not affected by the ground fault. In the short

term, this increased voltage load does not have a critical effect on the converter and motor but, over extended

periods of operation (more than 24 hours), it can reduce the lifetime of the motor winding. For this reason, it is

absolutely essential that ground faults are detected promptly by an insulation monitor.

The insulation monitor can be installed at a central location in the IT system or in the SINAMICS converter itself.

Monitors supplied by Bender, for example, are proven and fit for this purpose.

Insulation monitors are available as option L87 for SINAMICS G150 and S150 converter cabinet units and for S120

Line Connection Modules. The signaling relays K1 and K2 must be parameterized as N.C. (Normally Closed) during

commissioning, i.e. the relays must be closed-circuit working and normally be closed (corresponds to condition "no

fault"). Consequently, the contacts drop out in the event of a fault on the insulation monitor. The fault can be detected

and signaled to a higher-level control. The parameter settings for the insulation monitor are described in the operating

instructions supplied with the converter units.

A common drive configuration that is operated as a non-grounded IT supply system is a 12-pulse drive, which is

supplied by a three-winding transformer. This transformer has one secondary winding with a star connection and

another with a delta connection. Since the delta-connected winding does not have a star point that can be properly

grounded, 12-pulse drives are operated with two non-grounded secondary windings i.e. as an IT supply system. For

this reason, 12-pulse-operated converters such as 12-pulse-operated SINAMICS G150 parallel converters must be

equipped with option L87 / insulation monitor.

Insulation resistance

SINAMICS G130, G150 and S150 Chassis and cabinet units and S120 Chassis and Cabinet Modules are equipped

with electronic circuits on the Control Interface Module CIM for measuring the DC link voltage. These circuits provide

galvanic isolation between the power unit and the grounded converter electronics. The insulation resistance is

therefore inherently very high (> 10 MΩ), even when a large number of these devices are operated together on the

same IT system.

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The only exception (until spring 2013) was the Voltage Sensing Module VSM10 (6SL3053-0AA00-3AA0) which

measured the line voltage for S120 Active Infeeds, S120 Smart Infeeds and for SINAMICS S150 cabinet units by

means of high-resistance resistor chains. The insulation resistance for the specified infeeds and cabinet units was

therefore 0.625 MΩ. The upgraded VSM10 Voltage Sensing Module (6SL3053-0AA00-3AA1) in which the power

circuitry is galvanically isolated from the grounded electronic circuitry of the converter has been available since spring

2013. This means that a very high insulation resistance in excess of > 10 MΩ can be achieved with this module even

if a large number of these devices are operated within the same IT system.

Note:

The upgraded VSM10 Voltage Sensing Module VSM10 (6SL3053-0AA00-3AA1) has a connector (X530) via which

the internal voltage sensing circuit can either be connected to or disconnected from ground potential.

In new converter units that are shipped with the new VSM10 (article number ends in 3AA1), the jumper in

connector X530 can be removed during commissioning in IT systems so as to achieve a galvanically isolated voltage

sensing circuit and thus an insulation resistance of > 10 MΩ.

In old converter units in which the new VSM10 (article number ends in 3AA1) is installed as a replacement module

for an old VSM10 (article number ends in 3AA0), the jumper must not be removed from connector X530 for safety

reasons. This is because the interference suppression capacitors must be discharged via the VSM10 module, if in IT

systems the interference suppression filters installed as standard in SINAMICS devices for the "second environment"

are not connected to ground owing to removal of the grounding strap. Consequently, the insulation resistance that

can be achieved in IT systems with the new VSM10 is similar to the value possible with the old VSM10.

The table below lists the insulation resistances of SINAMICS electronics boards which provide a high-resistance

connection between the power unit and grounded electronics as well as the resultant insulation resistances of

complete SINAMICS converters and SINAMICS S120 components.

Electronic circuit / SINAMICS electronics board Insulation resistance to ground Remark

Voltage Sensing Module VSM old (until spring 2013) 0.625 MΩHigh-value resistances

SINAMICS converter / SINAMICS component Insulation resistance to ground Remark

G130 Chassis unit > 10 MΩ

G150 cabinet unit > 10 MΩ

S150 cabinet unit With old VSM: 0.625 MΩ

With new VSM: >10 MΩ

Value for new VSM applies

when jumper has been

removed from X530

S120 Basic Infeed equipped with thyristors

(all Basic Line Modules sizes FB, FBL, GB, GBL) > 10 MΩ

S120 Basic Infeed equipped with diodes:

900 kW / 400 V and 1500 kW / 500 V - 690 V > 10 MΩ

S120 Smart Infeed With old VSM: 0.625 MΩ

With new VSM: >10 MΩ

Value for new VSM applies

when jumper has been

removed from X530

S120 Active Infeed With old VSM: 0.625 MΩ

With new VSM: >10 MΩ

Value for new VSM applies

when jumper has been

removed from X530

S120 Motor Module >10 MΩ

Insulation resistances of SINAMICS electronics boards, SINAMICS converters and SINAMICS S120 components

RFI suppression / RFI suppression filter

When installing or commissioning SINAMICS devices in an IT supply system, the grounding connection for the RFI

suppression filters found as standard in SINAMICS devices and designed for the “second environment” (category C3

in accordance with the EMC product standard EN 61800-3) must be opened. This can be done simply by removing a

metal clip on the filter as described in the operating instructions. If this is not done, the capacitors of the suppression

filters will be overloaded and possibly destroyed by a ground fault at the motor side (see section "Voltage conditions

in normal operation and in the event of a ground fault"). When the grounding connection for the standard RFI

suppression filter has been removed, the devices meet category C4 in accordance with the EMC product standard

EN 61800-3. For more information, refer to the chapter “EMC Installation Guideline”.

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Surge suppression

The lack of ground connection in IT supply systems means that the line voltage can theoretically drift by any amount

from ground potential, so that surge voltages to ground of infinite magnitude would be possible. This fortunately does

not happen in practice because the line voltage is grounded by the capacitances of the transformer winding and the

mains supply conductors, as described in the section "Voltage conditions in normal operation and in the event of a

ground fault". This grounding by capacitances ensures that the neutral of the ungrounded system is practically at

ground potential in normal, symmetrical three-phase operation and the voltage conditions in the IT system in relation

to ground are very similar to those in TN and TT systems.

In the event of a ground fault (when a ground fault develops in the converter DC link, at the inverter output, at the

motor cable or the motor itself), however, an operational voltage with respect to ground that is 2 times higher than in

the TN system develops. Under these conditions, therefore, the drive system no longer has any large reserves with

respect to its insulation. For this reason, transient overvoltages injected into the system from an external source (e.g.

due to switching operations in the medium-voltage power supply or by lightning strikes) are deemed to be more

critical in this situation than during normal operation. A risk of transient overvoltages to ground which can cause

equipment damage is especially high in complex installations with large numbers of converters.

For this reason, the installation of surge arresters to ground in IT networks is recommended. A single-phase surge

arrester must be connected between each phase and ground and located where possible directly in the main

distribution board downcircuit of the infeed transformer, or at the input of the converter system. Suitable surge

arresters are available from suppliers such as Dehn. As a result of the increased voltage stresses caused by ground

faults (see above), the rated voltages of the surge arresters must not be lower than the values specified in the table

below so as to prevent them to come into effect when the drive is operating normally.

Line supply voltage Minimum rated voltage of the

surge arrester, single-phase

Suitable type / supplied by Dehn

380 V – 480 V 3AC 600 V DEHNguard DG S 600 FM

500 V – 600 V 3AC 1000 V DEHNguard DG 1000 FM

660 V – 690 V 3AC 1000 V DEHNguard DG 1000 FM

Recommended rated voltages for surge arresters to ground in IT systems

If the rated voltages of the surge arresters are too low, the arresters can sustain damage as a result of periodically

comming into effect in normal operation or in operation with ground fault, or they may cause EMC-related problems in

the system such as malfunctions in installed insulation monitors.

Surge arresters for operation on an IT system are available as option L21 for SINAMICS G150 and S150 cabinet

units and for the Line Connection Modules of the SINAMICS S120 Cabinet Modules. This option provides the

installation of the surge arresters including the appropriate fuses. The signaling contacts of the surge arresters are

connected in series for monitoring purposes and routed to a customer interface.

Note:

Option L21 does not include the installation of an insulation monitor for the IT system. An insulation monitor must

always be ordered separately as option L87 if the supply system is not monitored at any other point by an insulation

monitor. Only one insulation monitor can ever be used within the same electrically-connected network.

Option L21 does not include factory removal of the metal clip that connects the interference suppression filter to

ground, nor does it include removal of the grounding jumper in connector X530 of the VSM10 Voltage Sensing

Module for SINAMICS S120 Active Infeeds / Smart Infeeds and SINAMICS S150 cabinet units. The metal clip that

connects the interference suppression filter to ground, or the grounding jumper at the VSM10 Voltage Sensing

Module must therefore be removed during installation or commissioning of the converter if the supply system at the

installation site is an IT system.

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1.2.7 Connection of converters to supply systems with different short-circuit powers

Definition of the relative short-circuit power RSC

According to EN 60146-1-1, the relative short-circuit power RSC is defined as the ratio between the short-circuit

power SK Line of the supply system and the rated apparent power (fundamental apparent power) SConverter of the

converter at its point of common coupling PCC.

Supply systems with high relative short-circuit power RSC > 50 (strong systems)

Relative short-circuit powers of RSC > 50 always require the installation of line reactors for 6-pulse rectifier circuits

(G130, G150, S120 Basic Line Modules and S120 Smart Line Modules). These limit the line-side current harmonics

and protect the converter (rectifier and DC link capacitors) against thermal overloading. No special conditions apply in

the case of 6-pulse rectifier circuits with Line Harmonics Filters (LHF and LHF compact) or Active Infeeds (S150,

S120 Active Line Modules).

Supply systems with medium relative short-circuit power 15 ≤ RSC ≤ 50

Supply systems with medium-level, relative short-circuit power in the 15 ≤ RSC ≤ 50 range do not generally

necessitate any special measures. Depending on the converter output power rating, it might be necessary to install

line reactors where 6-pulse rectifier circuits are used. No special conditions apply in the case of 6-pulse rectifier

circuits with Line Harmonics Filters (LHF and LHF compact) or Active Infeeds (S150, S120 Active Line Modules).

Supply systems with low relative short-circuit power RSC < 15 (weak systems)

If SINAMICS converters are connected to supply systems with a low, relative short circuit power RSC < 15, it must be

noted that not only the supply system perturbation, i.e. the voltage harmonics in the line voltage, is increasing but

also other undesirable side-effects may occur. For this reason, the minimum permissible value of the relative short-

circuit power for SINAMICS units is about RSC = 10.

If the RSC value drops to below 10 with a 6-pulse rectifier circuit, the voltage harmonics can reach critical levels. The

permissible harmonic limits specified in the standards are exceeded and reliable operation of the converter and other

equipment connected at the PCC can no longer be guaranteed. For additional information, please refer to "Standards

and permissible harmonics" in the section "Harmonic effects on supply system".

If the RSC value drops to below 10 on 6-pulse rectifier circuits with Line Harmonics Filters, the detuning of the Line

Harmonics Filter caused by the high impedance of the supply system will lead to a considerable increase of the

fundamental wave of the line voltage. This can reach values beyond the permissible line voltage tolerance of the

converters, which means that they cannot operate properly under supply conditions of this type.

Certain restrictions also have to be accepted in the case of Active Infeeds. With RSC values of < 15, the dynamic

response of the control becomes slightly worse and the voltage harmonics at the pulse frequency in the line voltage

begin to increase. RSC values of < 10 mean that reliable operation of the converter and other equipment connected

at the PCC can only be achieved at the cost of lower performance in terms of dynamic response and harmonic

effects. With RSC values of < 5, stable operation can only be achieved with major restrictions and the special

commissioning information / parameterization instructions for weak supply systems must be taken into account.

Relative short-circuit power values of RSC < 10 can be encountered, for example, when converters are supplied by

transformers of the correct power rating that have high relative short-circuit voltages (per unit impedances)

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of vk> 10 %. Generally RSC values are also < 10 when converters are operated on an island power supply created

by a diesel electric generator, because the value Xd´´ for generators (that corresponds to the value vk for

transformers) is typically in the range between 10 % to 15 %. In such cases, the power supply conditions must be

analyzed precisely. It is often necessary to consider overdimensioning the transformers or generators in order to

reduce voltage harmonics. When Infeeds with regenerative capability (Smart Infeeds or Active Infeeds) are supplied

by diesel-electric generators, the appropriate parameters should be set to prevent the system from operating in

regenerative mode.

An extremely weak network would be, for example, a very low-output laboratory or test bay supply on which a high-

powered, variable-speed drive needs to be tested. If the drive were operated only under no-load conditions, there

could be no objection to this type of constellation. Very little active power is required under no load and the supply

system would not be overloaded in terms of power drawn. A basic prerequisite, however, is that the mains system

can supply the precharging current to precharge the DC link. The magnitude of the precharging current depends on

the unit type and is stated in the sections on specific unit types.

As long as the converter is designed as a 6-pulse rectifier without Line Harmonics Filter at the input side

(SINAMICS G130, G150 and S120 Basic Line Modules), the harmonic effects on the supply are also limited by virtue

of the low line currents, which means that this type of arrangement is perfectly suitable for test purposes. An

exception among the 6-pulse rectifiers is the SINAMICS S120 Smart Line Module, because this draws a significant

harmonic reactive current from the supply system, even under no-load conditions. For this reason, the regenerative

direction should be disabled in the firmware of Smart Line Modules if they are employed for the test purposes

described above.

Although 6-pulse drives with Line Harmonics Filters present no problems with respect to harmonics, there is still a

risk, as described above, that the fundamental wave of the line voltage will significantly increase due to detuning of

the filter, which means that the system can no longer function properly.

When high-power drives with Active Infeeds need to be tested (SINAMICS S150 or drives with S120 Active Line

Modules), an arrangement of this type is critical with respect to harmonics. The harmonics at the line side, which are

normally kept very low by the Clean Power Filter, can cause such distortions in the line voltage with RSC values of

< 5, even at no load, due to the high impedance of the weak network that the closed-loop control of the Active Infeed

starts to malfunction. Only by observing the special setting and parameterization recommendations for weak supply

systems stable low-load operation for test purposes can be reliably achieved for RSC values of ≥ 2.5.

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1.2.8 Supply voltage variations and supply voltage dips

General

The voltage of the power supply systems is usually not constant but rather susceptible to noticeable changes, as a

result of load variations, switching operations and individual occurrences, such as short circuits. The connected

SINAMICS units are inevitably affected by these changes and show different reactions to them, depending on the

magnitude and duration as well as on the operating conditions of the drive. These reactions range from entirely

unaffected operation over operation with certain restrictions to the complete drive shut-down.

The following paragraphs deal with the most important types of supply voltage changes, their causes, magnitude and

duration. Afterwards the behaviour of SINAMICS units during supply voltage variations and supply voltage dips will

be explained.

Supply voltage variations are relatively slow, long-term increases or decreases of the RMS value (root mean

square value) of the supply voltage, which usually occur as a result of load variations in the power supply system, the

switching of the transformer tap changers and other operational adjustments in the power supply system.

According to EN 61000-2-4, it is possible, in European interconnected supply systems, to assume the following

typical variations in the nominal supply voltage VN:

· 0.90 • VN ≤ VLine ≤ 1.1 • VN (continuously)

· 0.85 • VN ≤ VLine ≤ 0.9 • VN (short-term, i.e. < 1 min)

Supply voltage dips are characterized by a sudden decrease in the supply voltage, followed by a restoration shortly

afterward. Supply voltage dips are usually associated with the emergence and disappearance of short-circuits or

other very large current increases in the supply (e.g. the starting of relatively large motors directly at the supply with

correspondingly high starting currents). Supply voltage dips vary quite a lot with regard to their depth and duration.

The depth of a supply voltage dip depends on the location of the short circuit and the current increase. If this occurs

close to the unit’s connection point, the dip will be large, if it occurs far away from the connection point, it will be

small. The duration of the dip depends, when short circuits occur in the supply system, how quickly the protection

device, such as fuses or circuit breakers, respond and clear the short circuit.

In European interconnected supply systems, it is possible, according to EN 50160, to assume the following

approximate values for supply voltage dips:

0.01 • VN ≤ VLine ≤ VN (very short-term, i.e. 10 ms to approx. 1 s)

The following diagram shows supply voltage dips in a typical, European interconnected supply system over a time

period of two months. The supply voltage dips are in the range of 0.5 • VN ≤ VLine ≤ VN

with a duration of between

50 ms and 200 ms, whereby very large dips occur very seldom.

Supply voltage dips in a typical European interconnected supply system

Outside Europe, larger and longer supply voltage dips can occur more frequently, particularly in states with fewer

closely connected power supply systems, such as those in the USA, Russia, China or Australia. Here supply voltage

dips which last a second or longer must be expected.

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1.2.9 Behaviour of SINAMICS converters during supply voltage variations and dips

Supply voltage ranges

SINAMICS units are dimensioned for relatively wide supply voltage ranges, whereby each range covers several of

the worldwide nominal supply voltages VN. The converter Chassis units SINAMICS G130 and the converter cabinet

units SINAMICS G150 are available in three supply voltage ranges. The components of the modular system

SINAMICS S120 (Chassis and Cabinet Modules) as well as converter cabinet units SINAMICS S150 are available in

two supply voltage ranges. The supply voltage range of the units has to be selected so that the on-site nominal

supply voltage VNis within the permissible supply voltage range.

SINAMICS unit Permissible nominal supply voltage range V

SINAMICS G: 380 V ≤ VN ≤ 480 V 3AC

G130 / G150 500 V ≤ VN ≤ 600 V 3AC

660 V ≤ VN ≤ 690 V 3AC

SINAMICS S: 380 V ≤ VN ≤ 480 V 3AC

S120 (Chassis and Cabinet Modules) and S150 500 V ≤ VN ≤ 690 V 3AC

Supply voltage ranges for SINAMICS G130, G150, S120 (Chassis and Cabinet Modules) and SINAMICS S150

During commissioning, the units must be set up to the on-site available nominal supply voltage VN:

· Hardware set-up: Adaptation of the line-side transformer tap for the internal supply of auxiliaries

with 230 V and adaptation of the line-side transformer tap for the supply of the

fans with 230 V.

· Firmware set-up: Adaptation of parameter P0210 / Supply voltage

These settings are absolutely essential, in order that the units behave optimally during supply voltage variations. On

the one hand, they ensure that the units are as insusceptible as possible to supply voltage variations and that

unnecessary fault trips are avoided. On the other hand, they also ensure that the units react to unacceptably large

supply voltage changes with prompt fault trips, thus avoiding any damage being incurred to the units.

The hardware settings also guarantee a sufficient level for the 230 V produced by the transformers for the auxiliaries

and the fans at lower supply voltage and prevent the overloading of the 230 V auxiliaries when the supply voltage is

increased.

The firmware settings ensure an optimal adaptation of the under and over-voltage trip levels of the DC link voltage.

For all further considerations, it is assumed that the units are set-up correctly in terms of hardware and firmware,

accordning to the on-site available nominal supply voltage VN.

Continuously permissible supply voltage variations

Continuous operation of SINAMICS units is permissible in the following range of the nominal supply voltage:

0.9 • VN ≤ VLine ≤ 1.1 • VN

In this supply voltage range, all the auxiliaries supplied with 230 V by the internal transformer operate within their

permissible limits and also the fans supplied with 230 V by an internal transformer are able to fully provide the cooling

air flow required by the power components within the limits of the permissible frequency tolerances. The DC link

voltage has a wide safety margin to the under and over-voltage trip level regardless of whether a regulated rectifier

(Active Infeed) or unregulated rectifier (Basic Infeed or Smart Infeed) is used.

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At higher supply voltage of VN ≤ VLine ≤ 1.1 • VN no restrictions in the operational behaviour of the drive need to be

taken into consideration.

At lower supply voltage of 0.9 • VN ≤ VLine ≤ VN it must be taken into consideration that the drive power decreases in

proportion to the supply voltage. If a power reduction cannot be tolerated, converter and motor must have current

reserves, in order to compsenate for the lower supply voltage with an increased current input. This may make the

over-dimensioning of the drive necessary.

Short-term permissible supply voltage variations (< 1 min)

Short-term operation (i.e. up to 1 min) of SINAMICS units is permissible within the following range of the nominal

supply voltage:

0.85 • VN ≤ VLine ≤ 0.9 • VN

In this range all the auxiliaries supplied with 230 V by the internal transformer still operate within their permissible

limits, but the fans also supplied with 230 V by an internal transformer can no longer, within the range of permissible

frequency tolerances, fully provide the cooling air flow required by the power components. As a result of this reduced

cooling capacity, operation must be limited to a time period of < 1 min. The DC link voltage still has a wide safety

margin to the under and over-voltage trip level regardless of whether a regulated rectifier (Active Infeed) or

unregulated rectifier (Basic Infeed or Smart Infeed) is used.

In this short-term, permissible supply voltage range, it must also be taken into consideration that the drive power

decreases in proportion to the supply voltage. If a power reduction cannot be tolerated, the converter and motor must

have current reserves in order to compensate for the reduced supply voltage with a higher current input. This may

mean that the drive has to be over-dimensioned.

Permissible supply voltage dips

On the following pages, dips which do not cause fault tripping of the drive will be termed permissible supply voltage

dips. That no fault trip occurs, two conditions must be fulfilled:

· All auxiliaries in the converter, which are supplied with 230 V – with the exception of the fans – and also the

electronics supplied with 24 V DC, must remain in operation,

and

· the DC link voltage must not reach the undervoltage trip level in motor operation, or

the overvoltage trip level in generator operation.

Whether these conditions can be fulfilled during supply voltage dips depends on a lot of factors. These factors are:

· The supply of auxiliaries with 230 V and the supply of the electronics with 24 V DC (directly from the power

supply, via the internal transformer or from a secure, external supply e.g. an uninterruptible power supply)

· The type of the SINAMICS lnfeed (regulated or unregulated)

· The load condition of the drive (full load, partial load or no-load)

· The depth of the supply voltage dip

· The duration of the supply voltage dip

The supply for the auxiliaries (230 V AC) and for the electronics (24 V DC) is produced in the cabinet units

SINAMICS G150, S120 Cabinet Modules and S150, depending on the specific device, either as standard or as an

option via built-in transformers internal to the units, which are supplied directly by the power supply voltage.

Consequently, the supply voltage dips have an effect directly on the auxiliaries supplied with 230 V. If the supply

voltage dips too much and over a too long time period, the auxiliaries (including the internal switch-mode power

supply for the 24 V supply for the electronics) will fail. This leads to a fault trip.

If the voltage of the auxiliaries (230 V) and the electronics (24 V) should remain in operation even during large and

long supply voltage dips, the voltage of 230 V must be supplied from a secure, external supply, such as an

uninterruptible power supply (UPS). To connect the external 230 V supply to cabinet units with integrated

transformers two wire jumpers must be removed as illustrated in the diagram below by the example of a G150

cabinet unit. Also the voltage of 24 V can be supplied from a secure, external supply by disconnecting the internal

switch-mode power supply and replacing it by a secure, external supply.

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Supply of the auxiliaries with 230 V AC and of the electronics with 24 V. Example with a SINAMICS G150 cabinet unit.

The type of the SINAMICS Infeed (rectifier) determines the relationship between the supply voltage and the DC link

voltage. Further information on this can be found in the section “SINAMICS Infeeds (rectifiers) and their properties”.

The line-commutated, unregulated Infeeds SINAMICS Basic Infeed and SINAMICS Smart Infeed generate a DC link

voltage, which is at stationary operation in proportion to the supply voltage. If the supply voltage dips, the energy flow

from the supply to the DC link is interrupted until the DC link voltage has, as a result of the load current, fallen to a

voltage level which corresponds to the supply voltage which has dipped. If this voltage level is below the under-

voltage trip level of the DC link, the energy flow from the supply to the DC link is completely interrupted. In this case

the drive can only use the electrical energy stored in the DC link capacitors and can only continue to operate until the

DC link voltage has dropped to the value of the under-voltage trip level by means of the load current on the motor

side. This time span is in the range of a few milliseconds and depends on the load conditions of the drive. It

decreases as the load increases so that at full load, only small supply voltage dips of a few milliseconds can be

overcome without fault tripping.

The self-commutated, regulated Infeed, SINAMICS Active Infeed, operates as a step-up converter and can regulate

the DC link voltage, almost independently of the supply voltage, to a constant value. As a result, the energy flow from

the supply to the DC link can also be maintained during serious supply voltage dips. As long as the reduced power,

as a result of the lower supply voltage, can be compensated for by a higher input current, the drive is able to

overcome deep and prolonged supply voltage dips, without a fault trip. It must be noted that the modulation depth of

the Active Infeed alters significantly during deep supply voltage dips by comparison with normal operation. As a

result, the harmonic effects on the supply system increase and the Clean Power Filter in the Active Interface Module

AIM of the Active Infeed is also subjected to a higher thermal load. For these reasons, operation during periods of

very deep supply voltage dips is permissible for only a few minutes.

The following pages will deal with the behaviour of the unregulated and regulated SINAMICS Infeeds in view of the

above-mentioned considerations.

Permissible supply voltage dips with the unregulated SINAMICS Infeeds, Basic Infeed and Smart Infeed

In order to explain the behaviour of SINAMICS drives with line-commutated, unregulated Infeeds, all theoretically

possible supply voltage dips with regard to magnitude and duration are devided into six different ranges, named A to

F. In the following diagram, these ranges are shown for unregulated SINAMICS Infeeds, whereby each range

corresponds to different boundary conditions and, therefore, to a different behaviour of the drive.

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Division of all supply voltage dips according to magnitude and duration in the ranges

A to F for the description of the behaviour of SINAMICS drives with unregulated Infeeds

Range A

Range A comprises supply voltage dips, the magnitude of which is in the long and short-term ranges of permissible

supply voltage variations.

Dips in range A are, therefore, permissible, with the restriction that the DC link voltage and the drive power decrease

in proportion to the magnitude of the supply voltage dips.

Range B

Range B comprises supply voltage dips, the magnitude of which reaches values of VLine/VN ≈ 0.75. The DC link voltage

which is in proportion to the supply voltage is still over the under-voltage trip level in the DC link but the auxiliaries which are

supplied with 230 V by the internal transformer do not function any more after a few milliseconds.

Dips in range B are, therefore, only permissible when the supply of the auxiliaries with 230 V is done via a secure,

external source. It must also be taken into consideration that the DC link voltage and the drive power decrease in

proportion to the magnitude of the supply voltage dip.

Range C

Range C comprises very short supply voltage dips of any magnitude, the duration of which is up to 5 ms. During this

time, the current required by the load is delivered entirely by the DC link capacitors, thus causing the DC link voltage

to decrease. As a result of the extremely short duration of the dip, the DC link voltage still does not reach the under-

voltage trip level, even at 100 % load. The auxiliaries supplied with 230 V also remain in operation.

Dips in range C are, therefore, as a result of the extremely short duration, permissible without restrictions.

Range D

Range D comprises very short supply voltage dips of any magnitude, the duration of which is up to 10 ms. During this

time, the current required by the load is delivered entirely by the DC link capacitors, thus causing the DC link voltage

to decrease. The DC link voltage then only does not reach the under-voltage trip level, if the DC link is discharged

more slowly than in range C. Therefore, the drive can be operated with a maximum load of approx. 50 %. Due to the

still relatively short duration, it can be assumed that the auxiliaries which are supplied with 230 V will remain in

operation.

Dips in range D are, therefore, as a result of the very short duration, permissible, as long as the drive is operating at

partial load with a maximum of 50 %.

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Range E

Range E comprises short supply voltage dips of any magnitude, the duration of which is up to 50 ms. During this

time, the current required by the load is delivered entirely by the DC link capacitors, whereby the DC link voltage

decreases. The DC link voltage then only does not reach the under-voltage trip level, if the DC link is discharged

more slowly than in range D. Therefore, the drive can only be operated with no load. The auxiliaries, which are

supplied with 230 V directly from the supply via the internal transformer, do not remain in operation.

Dips in Range E are, therefore, only permissible if the auxiliaries are supplied from a secure, external supply and the

drive is in no-load operation.

Range F

Range F comprises supply voltage dips, the magnitude and duration of which is so large, that, independently of the

load, a fault trip due to under-voltage in the DC link cannot be avoided.

Dips in range F are, therefore, not permissible.

Note:

The statements – particularly the time specifications – regarding ranges C to E are precisely accurate only in relation

to single drives (e.g. for SINAMICS G130 or G150). In the case of multi-motor drives, the specified times might be

much longer depending on the drive constellation and operating conditions. This might be true, for example, if

inverters which are in standby mode during normal operation but raise the DC link capacitance of the drive

configuration, are connected to the DC busbar of the drive configuration. The times can also be significantly longer in

DC drive configurations in which some of the drives operate in motor mode and others in generator mode. These

influencing factors mean that no generally valid statements can be made about multi-motor drives and each drive

configuration must therefore be assessed individually.

Permissible supply voltage dips with the regulated SINAMICS Active Infeed

In order to explain the behaviour of SINAMICS drives with self-commutated, regulated Infeeds, all theoretically

possible supply voltage dips with regard to magnitude and duration are divided into six, different ranges, named A to

F. In the following diagram, these ranges are shown for regulated SINAMICS Infeeds, whereby each range

corresponds to different boundary conditions and, therefore, to a different behaviour of the drive.

Division of all supply voltage dips according to magnitude and duration in the ranges

A to F for the description of the behaviour of SINAMICS drives with regulated Infeeds

Range A

Range A comprises supply voltage dips, the magnitude of which is in the long and short-term ranges of permissible

supply voltage variations.

Dips in range A are, therefore, permissible, with the restriction that the DC link voltage and the drive power decrease

in proportion to the magnitude of the supply voltage dips.

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Range B

Range B comprises supply voltage dips, the magnitude of which reaches values of VLine/VN ≈ 0.5. As a result of the

regulated operation, the DC link voltage can be maintained at its pre-set value, as long as the reduced supply voltage

can be compensated for with an increased input current. The auxiliaries supplied with 230 V via the internal

transformer, do not, however, remain in operation.

Dips in range B are, therefore, only permissible when the supply of the auxiliaries with 230 V is done via a secure,

external source. It must also be taken into consideration that the DC link voltage and the drive power decrease in

proportion to the magnitude of the supply voltage dip.

Since the modulation depth of the Active Infeed alters significantly during deep supply voltage dips at the lower end

of range B by comparison with normal operation, the harmonic effects on the supply system increase and the Clean

Power Filter in the Active Interface Module AIM of the Active Infeed is also subjected to a higher thermal load. For

these reasons, operation at the lower end of range B is permissible for only a few minutes.

Range C

Range C comprises very short supply voltage dips of any magnitude, the duration of which is up to 5 ms. During this

time, the current required by the load is mainly delivered by the DC link capacitors, thus causing the DC link voltage

to decrease. Due to the extremely short duration, the DC link voltage does not reach the under-voltage trip level,

even at 100 % load. The auxiliaries supplied with 230 V also remain in operation.

Dips in range C are, therefore, as a result of the extremely short duration, permissible without restrictions.

Range D

Range D comprises very short supply voltage dips of any magnitude, the duration of which is up to 10 ms. During this

time, the current required by the load is mainly delivered by the DC link capacitors, thus causing the DC link voltage

to decrease. The DC link voltage then only does not reach the under-voltage trip level, if the DC link is discharged

more slowly than in range C. Therefore, the drive can be operated with a maximum load of 50 %. Due to the relatively

short duration, it can be assumed that the auxiliaries supplied with 230 V will remain in operation.

Dips in range D are, therefore, as a result of the very short duration, permissible, as long as the drive is operating at

partial load with a maximum of 50 % load.

Range E

Range E comprises short supply voltage dips of any magnitude, the duration of which is up to 50 ms. During this

time, the current required by the load is mainly delivered by the DC link capacitors, whereby the DC link voltage

decreases. The DC link voltage then only does not reach the under-voltage trip level, if the DC link is discharged

more slowly than in range D. Therefore, the drive can only be operated with no load. The auxiliaries, which are

supplied with 230 V directly from the supply via the internal transformer, do not remain in operation.

Dips in Range E are, therefore, only permissible if the auxiliaries are supplied from a secure, external supply and the

drive is in no-load operation.

Range F

Range F comprises supply voltage dips, the magnitude and duration of which is so large, that, independently of the

load, a fault trip due to under-voltage in the DC link cannot be avoided.

Dips in range F are, therefore, not permissible.

Note:

The statements – particularly the time specifications – regarding ranges C to E are precisely accurate only in relation

to single drives (e.g. for SINAMICS G150). In the case of multi-motor drives, the specified times might be much

longer depending on the drive constellation and operating conditions. This might be true, for example, if inverters

which are in standby mode during normal operation but raise the DC link capacitance of the drive configuration, are

connected to the DC busbar of the drive configuration. The times can also be significantly longer in DC drive

configurations in which some of the drives operate in motor mode and others in generator mode. These influencing

factors mean that no generally valid statements can be made about multi-motor drives and each drive configuration

must therefore be assessed individually.

Summary of the drive behaviour during supply voltage dips

If one considers the behaviour of the unregulated and regulated SINAMICS Infeeds and also reflects upon the typical

distribution of supply voltage dips as shown in the diagram in the section “Suppy voltage variations and supply

voltage dips”, the following conclusions can be drawn.

Extremely large dips as those in the ranges C to E, during which the supply voltage dips to almost zero and the

energy flow from the supply to the DC link is essentially interrupted, can only be tolerated absolutely reliably,

independently from the kind of Infeed, for a time period of approximately 5 ms to a maximum of 50 ms, depending on

the load condition, because the energy stored in the DC link capacitors is very low. However, dips of such magnitude

and duration very rarely occur in practice.

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Longer dips of more than 50 ms can only be handled reliably if the energy flow from the supply to the DC link is

maintained or if favorable boundary conditions are given in the case of multi-motor drives.

With the line-commutated, unregulated Infeeds, Basic Infeed and Smart Infeed, this is only the case if the supply

voltage dips not lower than on values of approx. 75 % of the nominal supply voltage VN (ranges A and B). Without an

external auxiliary supply, 50 % of all typical supply voltage dips can be dealt with (range A), with an external auxiliary

supply, this increases to 70 % (ranges A and B).

With the self-commutated, regulated Infeed, SINAMICS Active Infeed, the energy flow from the supply to the DC link

is maintained even if the supply voltage dips to around 50 % of the nominal supply voltage (ranges A and B). Without

an external auxiliary supply, 50 % of all typical supply voltage dips can be dealt with as in the case with unregulated

Infeeds (range A). With an external auxiliary supply, however, this increases to almost 100 % (ranges A and B). Thus

the regulated SINAMICS Active Infeed offers clear advantages in comparison with the unregulated Basic and Smart

Infeed for supplies which often experience relatively large voltage dips.

Measures for the reduction of the effects of large and long supply voltage dips

Kinetic Buffering

Longer supply voltage dips of more than 50 ms and larger than 50 % of the nominal supply voltage VN corresponding

to range F can, due to the more or less interrupted energy flow from the supply to the DC link, be bridged without a

fault trip only if the motor can provide energy to buffer the DC link. This is the case at drives with sufficiently large

rotating masses. In such cases, the kinetic buffering function can be used. This function is included as a standard in

the firmware of SINAMICS converters and inverters and can be activated by parametrization when required. During a

supply voltage dip, the kinetic buffering function takes energy from the rotating masses for the buffering of the DC link

and thus prevents a fault trip. After the supply voltage dip the rotating masses are accelerated again. This procedure

can be used if sufficiently large rotating masses are available in order to buffer the supply voltage dip for a long

enough time period and if the driven process can tolerate a reversal in the direction of energy flow during the supply

voltage dip. With sufficiently large rotating masses, very large supply voltage dips and even supply voltage failures

which last for several seconds can be bridged without a fault trip of the drive.

Automatic Re-Start in combination with Flying-Restart

With deep and prolonged supply voltage dips within range F or with prolonged power outages, a fault trip is

unavoidable. This trip can be accepted in many applications, as long as the drive is able to re-start again by its own

after the voltage dip or voltage failure and as long as the drive is able to accelerate again to the original operating

condition. For this, the automatic re-start function can be used. If a re-start after a supply voltage dip is expected with

a rotating motor, the automatic re-start function must be combined with the flying re-start function.

The flying restart function detects the direction of rotation and the speed of the motor and accelerates the motor from

its current speed. The acceleration process can be started on condition that

- the motor is almost fully de-magnetized,

- the current speed has been detected (in encoderless operation), and

- the motor has been magnetized again.

The following diagram shows the typical flying restart sequence for an asynchronous (induction) motor operating

without an encoder.

ON / OFF command

Current,

actual value

Current

speed

nsearch max

nactual

Speed setpoint

Searching

De-magnetizing Magnetizing

Ramp-up

Flying restart of an encoderless asynchronous motor

Since the de-magnetizing time for small motors (< 100 kW) is a few seconds, and for large motors (> 1 MW) up to 20

seconds, very fast flying restart of large motors cannot be achieved unless additional measures are taken.

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A speed encoder can be used to make the flying restart process slightly faster than it is in encoderless operation.

This is because the current motor speed is immediately available thanks to the speed encoder and does not need to

be searched as it would in encoderless operation.

Flying restart of an asynchronous motor with speed encoder

A very fast flying restart can be achieved by installing a VSM10 Voltage Sensing Module at the inverter output. This

module measures the remanence voltage of the asynchronous motor. As a result, the degree of magnetization and

the speed of the motor are already known so that it is unnecessary to de-magnetize the motor or search the current

speed. The motor can be re-magnetized immediately and then accelerated.

The automatic restart and flying restart functions are implemented as standard in the converter firmware and can be

activated by parameterization if necessary.

For further information, please refer to the function manual "SINAMICS S120 Drive Functions".

1.2.10 Permissible harmonics on the supply voltage

SINAMICS converters and the corresponding line-side system components (line reactors, Line Harmonics Filter and

line filters) are designed for being connected to supplies with a continuous level of voltage harmonics, according to

EN 61000-2-4, Class 3. In the short-term (< 15 s within a time period of 2.5 min) a level of 1.5 times the continuous

level is permissible.

Harmonic Number

Class 1

Class 2

Class 3

5 3 6 8

7 3 5 7

11 3 3.5 5

13 3 3 4.5

17 2 2 4

17 < h ≤ 49 2.27 x (17/h) – 0.27 2.27 x (17/h) – 0.27 4.5 x (17/h) – 0.5

Compatibility level for harmonics, according to EN 61000-2-4

– harmonic contents of the voltage V, odd harmonics, no multiples of 3

Class 1 Class 2 Class 3

Total Harmonic Distortion factor

THD(V)

5 % 8 % 10 %

Compatibility levels for the Total Harmonic Distortion factor of the Voltage THD(V) according to EN 61000-2-4

That means that no voltage harmonics higher than those given in the table under Class 3 may appear at the

connection point for SINAMICS units. This includes harmonics produced by the units themselves. This must be

guaranteed by means of correct engineering. If necessary, Line Harmonics Filters, 12-pulse solutions or Active

Infeeds may be used to stay within the limits of Class 3.

Otherwise, components in the converter itself or the corresponding line-side components may be thermically

overloaded or error functions may occur in the converter.

Further information can be found in the section “Harmonic effects on the supply system”, under the subsection

“Standards and permissible harmonics”.

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1.2.11 Summary of permissible supply system conditions for SINAMICS converters

The table below provides a brief overview of the permissible supply system types, line voltages and supply system

conditions with which SINAMICS converters are compatible.

Permissible limits Relevant standard

Supply system types:

grounded TN and TT systems

- with grounded neutral

- with grounded phase conductor

ungrounded IT systems

permissible up to rated line voltage of 690 V

permissible up to rated line voltage of 600 V

permissible up to rated line voltage of 690 V

IEC 60364-1

Rated line voltages:

for SINAMICS G130 and G150:

for SINAMICS S120 and S150

380 - 480 V 3AC

500 - 600 V 3AC

660 - 690 V 3AC

380 - 480 V 3AC

500 - 690 V 3AC

Line voltage fluctuations or

slow rates of voltage change:

continuous

short-time ( < 1 min)

-10 % to +10 %

-15 % to +10 %

EN 61000-2-4 / Class 3

Line voltage unbalance:

long-time ( > 10 min) 3 % (negative-sequence system referred to the

positive-sequence system) EN 61000-2-4 / Class 3

Line voltage harmonics up to 50th-order

component:

Total Harmonic Distortion THD(V):

continuous

short-time ( < 15 s in 2.5 min)

10 %

15 %

EN 61000-2-4 / Class 3

Rated line frequency range:

47 Hz to 63 Hz - -

Line frequency fluctuations:

continuous

rate of change

-1 Hz to +1 Hz

Basic Infeed 0.5 Hz per second

Smart Infeed 0.5 Hz per second

Active Infeed 1.0 Hz per second

EN 61000-2-4 / Class 3

Permissible supply system types, line voltages and supply system conditions for SINAMICS converters

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1.2.12 Line-side contactors and circuit breakers

General

Line-side, electromagnetically actuated switchgear is required in many applications in order to automatically

connect/disconnect the SINAMICS converters to/from the supply system. In some instances, electromagnetically

actuated switchgear is an essential requirement, for example, if it is needed to precharge the DC link or to implement

the safety functions EMERGENCY OFF or EMERGENCY STOP which require automatic electrical isolation of the

converter from the supply system.

Contactors or circuit breakers can be used as electromagnetically actuated switchgear on the line side. These are

available as system components for SINAMICS G130 Chassis units and for the modular SINAMICS S120 Chassis

units (catalogs D 11 and D 21.3). Contactors or circuit breakers are either available as an option or installed as

standard (depending on the unit type) in SINAMICS G150 and S150 cabinet units and SINAMICS S120 converter

cabinet units in Cabinet Modules format.

For the SINAMICS devices described in this engineering manual, contactors are recommended as system

components for Chassis units with rated currents of ≤ 800 A and circuit breakers for Chassis units with rated currents

of > 800 A. Contactors are also available as options or fitted as standard switchgear for cabinet units with rated

currents of ≤ 800 A and circuit breakers for cabinet units with rated currents of > 800 A.

Exception: With parallel connections of SINAMICS G150 converters, contactors are used as standard for rated

currents of < 1500 A and circuit breakers for rated currents of ≥ 1500 A.

Contactors from the SIRIUS 3RT1 range Circuit breakers from the SENTRON 3WL range

Contactors

Contactors are switchgear only and do not perform any protective function when making on a short circuit or breaking

a short circuit which has developed during operation. For this reason, the line-side short-circuit protection for the

converter must always be provided by use of the fuses recommended in the catalogs. Further information can be

found in section "Connection of converters to the supply system and protection of converters".

The rated current and the making, breaking and short-circuit capacity are the key selection criteria for contactors. As

a general rule, the rated current of the contactor should be higher than or equal to the rated input current of the

converter.

If the making current is higher than the making capacity or the breaking current is higher than the breaking capacity,

the contactor contacts can lift or bounce. The arcs produced when the contacts bounce cause the contact material to

liquefy, resulting finally in contact adhesion or welding.

The making currents of the line-side contactors always remain lower than the rated input currents of the SINAMICS

G130, G150, S120 (Chassis and Cabinet Modules) and S150 converters described in this engineering manual owing

to the precharging circuit design. As a result, it is possible to use contactors from utilization category AC-1 (switching

of resistive loads) which have a maximum making and breaking capacity which equals around 1.5 times their rated

current. These contactors must be selected according to the rated input currents of the converters. They are used for

SINAMICS G150 cabinet units, S120 cabinet units in Cabinet Modules format and S150 cabinet units up to currents

of 800 A. The contactors used belong to the SIRIUS 3RT1 range (switching of resistive loads / utilization category

AC-1). They have a mechanical service life of 10 million switching cycles and an electrical service life of 0.5 million

switching cycles.

With regular converter shutdown operations and automatic fault trips of the kind caused by overcurrents at the output

or excess temperatures, the internal sequence control of the converter first issues a pulse disable command for the

power components (thyristors, IGBTs) before sending an OPEN command to the contactor. As a result, the contacts

open under practically no load. When the safety functions EMERGENCY OFF, Category 0 (uncontrolled shutdown of

the drive with instantaneous isolation from the supply system) and EMERGENCY STOP, Category 1 (controlled

shutdown of the drive with subsequent isolation from the supply system) are triggered, the contactor safety

combination bypasses the internal sequence control to issue the pulse disable command for the power elements as

well as the OPEN command for the main contactor, thus forcing the main contactor to open. Owing to the mechanical

inertia of the main contactor, the contactors open under practically no load in this case as well.

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In the event of an internal short circuit in the power unit caused by spontaneous component failure, the line-side

short-circuit current is interrupted by tripping of the line-side fuses. The recommended fuse types can be found in

catalogs D 11 and D 21.3. The effects on the main contactor differ according to the fuse type used. These are

defined by the degree of damage which is specified for coordination types 1 and 2 according to IEC 60947-4-1.

When the only fuses installed on the line side of the converter are line fuses of type 3NA, it can be assumed that the

degree of damage to the main contactor from utilization category AC-1 (switching of resistive loads) will comply with

the requirements for coordination type 1:

The contactor is defective following a short circuit and thus unsuitable for further use. It must be repaired, if

possible, or replaced.

When dual-function fuses of type 3NE1 are installed on the line side of the converter, it can be assumed that the

degree of damage to the main contactor from utilization category AC-1 (switching of resistive loads) will comply with

the requirements for coordination type 2:

The contactor is still operative following a short circuit. However, the risk that the contacts have become

welded cannot be completely eliminated. Slight welding of the contactor contacts is permissible provided that

they can be separated easily again without any noticeable deformation. For this reason, the contactors

should if possible be examined for signs of welding after a short circuit event.

For further information about line-side fuse protection of the converters, please refer to section "Connection of

converters to the supply system and protection of converters".

Circuit breakers

Circuit breakers are switchgear which perform additional safety functions in the event of overloads, when making on

a short circuit or breaking a short circuit which has developed during operation.

The key selection criteria for a circuit breaker are the rated current, the response values of the delayed and the

instantaneous short-circuit releases as well as the short-circuit breaking capacity. As a general rule, the rated current

of the circuit breaker should be higher than or equal to the rated input current of the converter.

If the making current is higher than the response value of the delayed or instantaneous short-circuit release, the unit

might be immediately tripped by the circuit breaker during startup.

The making currents of the line-side circuit breakers always remain lower than the rated input currents of the

SINAMICS G130, G150, S120 (Chassis and Cabinet Modules) and S150 converters described in this engineering

manual owing to the precharging circuit design. These circuit breakers can therefore be selected according to the

rated input currents of the converters.

The input currents of SINAMICS converters contain harmonic components, the amplitudes of which are determined

by the type of rectifier circuit and the impedance of the supply system. These cause increased loading of the

thermally delayed overload releases. For this reason, the circuit breakers should be designed according to the rated

input currents in which the harmonic components of the input currents are already included.

With regular converter shutdown operations and automatic fault trips of the kind caused by overcurrents at the output

or excess temperatures, the internal sequence control of the converter first issues a pulse disable command for the

power components (thyristors, IGBTs) before sending an OPEN command to the line-side circuit breaker. As a result,

the contacts open under practically no load. When the safety functions EMERGENCY OFF, Category 0 (uncontrolled

shutdown of the drive with instantaneous isolation from the supply system) and EMERGENCY STOP, Category 1

(controlled shutdown of the drive with subsequent isolation from the supply system) are triggered, the contactor

safety combination bypasses the internal sequence control to issue the pulse disable command for the power

elements as well as the OPEN command for the circuit breaker, thus forcing the breaker to open. Owing to the

mechanical inertia of the circuit breaker, the contacts open under practically no load in this case as well.

In the event of an internal short circuit in the power unit caused by spontaneous component failure, the line-side

short-circuit current is interrupted (depending on its magnitude) either by the response of the short-time delayed

short-circuit release or by the response of the instantaneous short-circuit release of the circuit breaker.

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The table below shows the circuit breakers used in the different SINAMICS cabinet units depending on the line

supply voltage as well as the associated short-circuit breaking capacity for TN systems and IT systems without

ground fault. (Short-circuit breaking capacity for IT systems with ground fault on request).

SINAMICS cabinet unit Line supply

voltage

Circuit breaker

(type, size,

switching class)

Short-circuit

breaking capacity

G150

Single units > 800 A 1)

and

parallel units ≥ 1500 A 2)

380 – 480 V 3AC 3WL11 / I / N 55 kA

500 – 600 V 3AC 3WL12 / II / H 85 kA

660 – 690 V 3AC 3WL12 / II / H 85 kA

S150

Single units > 800 A 2) 380 – 480 V 3AC 3WL11 / I / N 55 kA

500 – 690 V 3AC 3WL12 / II / H 85 kA

S120 Cabinet Modules

Line Connection Modules

with currents > 800 A 2)

380 – 480 V 3AC 3WL12 / II / H 100 kA

500 – 690 V 3AC 3WL12 / II / H 85 kA

1) Circuit breaker can be ordered as option L26 2) Circuit breaker is included as standard

SINAMICS cabinet units:

Circuit breakers used and associated short-circuit breaking capacity for TN systems and IT systems without ground fault

SENTRON 3WL circuit breakers have a mechanical service life of 20,000 switching cycles (frame size I) or 15,000

switching cycles (frame size II).

Information about commissioning / Setting of rotary coding switches on electronic trip units (ETU)

The SENTRON 3WL circuit breakers installed in SINAMICS cabinet units are equipped with electronic trip units of

type ETU15B or ETU25B (depending on the unit type). These electronic trip units have a number of rotary coding

switches that need to be set correctly in order to ensure optimum protection of the SINAMICS cabinet unit.

Note:

The current setting values on the rotary coding switches (IR, Isd, Ii) are relative values that are referred to the rated

current In of the circuit breaker. For this reason, the converter input currents (converter rated input current IN In,

60-second overload current and 5-second overload current) must always be referred to the rated current In of the

circuit breaker.

Overload protection L (Long Time Delay)

The overload protection L can be set on electronic trip units ETU15B and ETU25B. The overload protection setting

should be at least equal to or slightly higher than the referred rated input current of the SINAMICS converter or the

SINAMICS infeed. It is then ensured that the converter can fully utilize its permissible continuous current and its

permissible overload reserves. Based on this requirement, the following values have to be set (depending on the unit

type and the associated ratio between the rated input current IN In of the converter or the infeed and the rated current

In of the circuit breaker):

IR = 0.7…..1.0 (unit-specific).

The values applicable to the specific unit types are specified in the relevant operating instructions.

Short-time delayed short-circuit protection (Short Time Delay)

The short-time delayed short-circuit protection S can be set on electronic trip units ETU25B. The values should be set

as low as possible and as fast as possible to ensure the fastest possible response of the circuit breaker to a short

circuit to minimize damage to the unit. Since the permissible range of operating currents for SINAMICS converters is

limited to a maximum of approximately 1.45 times the rated input current, the relative short-time delayed short-circuit

current should equal approximately 2 times the referred rated input current of the converter or infeed. The associated

delay time should be set to the lowest possible value. Based on this requirement, the setting values are thus as

follows:

Isd = 2,

tsd = 0.

These values are also specified in the relevant operating instructions.

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Instantaneous short-circuit protection (I = Instantaneous)

The instantaneous short-circuit protection I can be set on electronic trip units ETU15B. The value should be set as

low as possible to ensure the fastest possible response of the circuit breaker to a short circuit to minimize damage to

the unit. Since the permissible range of operating currents for SINAMICS converters is limited to a maximum of

approximately 1.45 times the rated input current, the relative instantaneous short-circuit current should equal

approximately 2 times the referred rated input current of the converter or infeed. Based on this requirement, the

setting value is thus as follows:

Ii = 2.

This value is also specified in the relevant operating instructions.

The relationships described above are explained below using the LSI characteristic of the electronic trip unit ETU25B

that is used in the Line Connection Modules of SINAMICS S120 Cabinet Modules. It is important to note that the

setting values for currents IR and Isd are relative values in each case that are referred to the circuit breaker rated

current In.

LSI characteristic of electronic trip unit ETU25B and recommended settings for rotary coding switches

The characteristic shown by the blue line limits the utilizable range of input currents of the converter or the infeed.

Currents to the left of the blue characteristic are permissible input currents while those to the right of the blue line

occur only in the event of a fault.

It is therefore necessary to set the tripping characteristic of the electronic trip unit such that it is always positioned to

the right of the blue characteristic, but is also as close as possible to the blue characteristic. The first condition must

be fulfilled in order to ensure that the permissible range of input currents can be fully utilized in operation, while

fulfilment of the second condition ensures the fastest possible response of the circuit breaker to faults. The

characteristic shown by the red line meets these criteria and is achieved by application of the specified setting values

IR =0.7….1.0 (unit-specific)

Isd = 2

tsd = 0.

The characteristic shown by the red line is placed on top of or between the characteristics shown by the black lines

which represent the limit settings of the electronic trip unit.

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It is absolutely essential to make the correct settings.

If IR is set too low, there is a risk that the converter or infeed will be tripped erroneously

when it is operating under high continuous load conditions. This can result in damage to

the installation or to the converter/infeed.

Very high setting values for the short-time delayed short-circuit current Isd and the

associated delay time tsd delay the response of the circuit breaker unnecessarily and can

therefore lead to significantly more extensive equipment damage.

Electronic trip unit

ETU25B

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1.3 Transformers

This section describes the process for selecting and dimensioning mains transformers.

1.3.1 Unit transformers

Unit transformers supply only a single converter and are specifically rated for its output power.

If a converter is supplied by a unit transformer, a line reactor does not generally need to be installed provided that the

relative short-circuit voltage vk of the transformer (per unit impedance) is ≥ 4 %.

Exceptions:

· With S120 Smart Infeeds, a line reactor must be installed unless the relative short-circuit voltage of the

transformer (per unit impedance) is vk ≥ 8%.

· In the case of converters with rectifiers connected in parallel, line reactors are required to provide balanced

current distribution in 6-pulse operation (SINAMICS G150 with 2 parallel-connected power units or S120

Basic Infeeds or S120 Smart Infeeds with parallel-connected power units).

1.3.1.1 General information about calculating the required apparent power of a unit transformer

The required apparent power S of the transformer is calculated according to the power balance of the drive which

must be supplied by the transformer.

The line-side active power P of the drive and the associated line-side active current I1 act are calculated on the basis

of the mechanical shaft power of the motor plus the power losses of the motor and converter.

Another factor to be considered is that a phase displacement φ1 develops between the line voltage (phase voltage

V1= VLine/√3) and the line-side fundamental current I1 with the line-commutated SINAMICS Infeeds (Basic Infeed and

Smart Infeed). Therefore a line-side fundamental reactive current I1 react and thus also a fundamental reactive power

Q1 occurs in addition to the line-side active current I1 act.

It must also be noted that additional harmonic currents Ih are superimposed on the line-side fundamental current I1 of

the drive. These increase the rms value of the line current, generate a distortive (reactive) power D and cause stray

losses in the transformer. The spectral composition and amplitudes of the individual harmonic currents Ih essentially

depend on the type of SINAMICS Infeed used and on the line-side impedance. For further information about the

harmonic currents of different SINAMICS Infeed types, please refer to sections "Harmonic effects on supply system"

and "SINAMICS Infeeds and their properties".

The line-side apparent power S of the drive thus comprises three components according to the relation

2DQPS ++= .

Key to formula:

· S……… Apparent power (total apparent power)

· P……… Active power:

This is calculated from the active component of the fundamental current (I1 act = I1 • cosφ1):

P = 3 • V1 • I1 • cosφ1.

It comprises the mechanical shaft power of the motor plus the power losses of the motor and

converter.

· Q

…...... Fundamental reactive power:

This is calculated from the reactive component of the fundamental current (I1 react = I1 • sinφ1):

Q1 = 3 • V1 • I1 • sinφ1.

· D……… Distortive (reactive) power:

This is calculated on the basis of the harmonic currents Ih:

¥=

××= h

IVD

The distortive (reactive) power is also referred to as "harmonic reactive power".

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The fundamental power factor cosφ1

The relation between the active power P and the fundamental apparent power S1 is referred to as the "fundamental

power factor cosφ1" and is defined as follows:

cos

reactact

act

The fundamental power factor cosφ1 of the different SINAMICS converters and Infeeds is dependent on the line

impedance or the Relative Short-Circuit power (RSC) at the PCC (Point of Common Coupling) and on the drive load.

The following table shows the typical values of the fundamental power factor cosφ1 for the SINAMICS converters and

Infeeds described in this engineering manual as a function of the relative short-circuit power RSC. The value for self-

commutated Infeeds (S120 Active Infeed and S150) can be parameterized in the firmware. The factory setting is "1".

Fundamental power factor cosφ1 for line-commutated SINAMICS converters and Infeeds

SINAMICS G130, G150, S120 Basic Infeed and S120 Smart Infeed

Relative short-circuit power RSC 100 % load

> 50 (strong line supply) ≈ 0.975

15 … 50 (medium line supply) ≈ 0.970

< 15 (weak line supply) ≈ 0.960

Fundamental power factor cosφ1 for line-commutated SINAMICS converters with LHF compact

SINAMICS G150 with option L01

Relative short-circuit power RSC 100 % load

No significant dependency on RSC ≈ 0.99 capacitive

Fundamental power factor cosφ1 for self-commutated SINAMICS converters and Infeeds

SINAMICS S120 Active Infeed and S150 with factory setting of cosφ1 to "1"

Relative short-circuit power RSC 100 % load

No significant dependency on RSC ≈ 1.00

Typical values of the fundamental power factor cosφ1 for SINAMICS converters and Infeeds

The total power factor λ

The relation between the active power P and the total apparent power S is referred to as the "total power factor λ"

and is defined as follows.

¥=

== h

hreactact

act

III

DQP

The total power factor λ of the different SINAMICS converters and Infeeds is dependent on the line impedance or the

Relative Short-Circuit Power (RSC) at the PCC (Point of Common Coupling) and on the drive load.

Since the total power factor λ includes the distortive (reactive) power D generated by harmonic currents as well as

the fundamental reactive power Q1, it is always smaller than the fundamental power factor cosφ1 in the case of line

currents with harmonic content.

The following table shows the typical values of the total power factor λ for the SINAMICS converters and Infeeds

described in this engineering manual as a function of the relative short-circuit power RSC.

The value for self-commutated Infeeds depends on the fundamental power factor cosφ1 parameterized in the

firmware for which the factory setting is “1”.

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Total power factor λ for line-commutated SINAMICS converters and Infeeds

SINAMICS G130, G150, S120 Basic Infeed and S120 Smart Infeed

Relative short-circuit power RSC 100 % load

> 50 (strong line supply) ≈ 0.87

15 … 50 (medium line supply) ≈ 0.90

< 15 (weak line supply) ≈ 0.93

Total power factor λ for line-commutated SINAMICS converters with LHF compact

SINAMICS G150 with option L01

Relative short-circuit power RSC 100 % load

No significant dependency on RSC ≈ 0.985

Total power factor λ for self-commutated SINAMICS converters and Infeeds

SINAMICS S120 Active Infeed and S150 with factory setting of cosφ1 to "1"

Relative short-circuit power RSC 100 % load

> 50 (strong line supply) ≈ 1.00

15 … 50 (medium line supply) ≈ 1.00

< 15 (weak line supply) ≈ 1.00

Typical values of the total power factor λ for SINAMICS converters and Infeeds

Note:

For the SINAMICS drives with unit transformers of the correct rating described in this engineering manual, the

relative short-circuit power RSC at the PCC of the converter as a result of the normal transformer impedance is

typically between RSC = 25 (transformer with vk = 4 %) and RSC = 15 (transformer with vk = 6.5 %).

1.3.1.2 Method of calculating the required apparent power S of a unit transformer

The required apparent power S of the unit transformer can be practically calculated with relative ease using the

formula below:

MotorConverter

hhl

*³

Key to formula:

· P Shaft power of the motor or output power of the matched converter

· η

Motor Motor efficiency

· η

Converter Converter efficiency

· λ Line-side total power factor

· k Factor which allows for the effects of transformer stray losses as a result of line-

side harmonic currents

For output power of > approx. 50 kW, i.e. the lowest converter rating for which unit transformers are used, the

following values are accurate approximations:

· η

Motor = 0.93 ... 0.97 η ≈ 0.93 for motor output of 50 kW rising to η ≈ 0.97 for motor output of 1MW

· η

Converter ≈ 0.98 For G130, G150 converters and converters with S120 Basic Infeeds or

S120 Smart Infeeds

· η

Converter ≈ 0.96 For S150 converters and converters with S120 Active Infeeds

· λ ≈ 0.93 For G130, G150 converters and S120 Basic Infeeds and S120 Smart Infeeds

· λ = 1 or λ = cos φAI For S150 converters and units with Active Infeed:

λ = 1, if cos φAI = 1 is parameterized with an Active Infeed (factory setting),

λ = cos φAI, if cos φAI ≠ 1 is parameterized with an Active Infeed

· k = 1.20 For systems with a standard distribution transformer and G130 without LHF,

G150 without LHF, S120 Basic Infeeds and S120 Smart Infeeds

· k = 1.15 For systems with a standard distribution transformer and

G130 or G150 with Line Harmonics Filters (LHF and LHF compact)

· k = 1.10 For systems with a standard distribution transformer and

S150 and S120 Active Infeeds

· k = 1.00 When a converter transformer is used irrespective of the converter type

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On the basis of the formula specified on the previous page and assuming that ηMotor ≈ 0.95 is the typical mean value

for the motor efficiency, the required rated apparent power S for the unit transformer is calculated as follows:

When a standard distribution transformer is used

S > 1.40 * P For G130 converters without LHF, G150 without LHF and

for converters with S120 Basic Infeeds and S120 Smart Infeeds

S > 1.30 * P For G130 or G150 converters with Line Harmonics Filters (LHF and LHF compact)

S > 1.20 * P /cos φAI For S150 converters and S120 converters with Active Infeeds

When a converter transformer is used

S > 1.15 * P For G130 converters with/without LHF, G150 with/without LHF and

for converters with S120 Basic Infeeds and S120 Smart Infeeds

S > 1.1 * P /cos φAI For S150 converters and S120 converters with Active Infeeds

The following output power ratings are standardized for unit transformers:

100 160 250 315 400 500 630 800 1000 1250 1600 2000 2500 [kVA]

The no-load ratio must be specified on the transformer order. The no-load voltage on the low-voltage side is generally

5 % higher than the voltage under full load. If, for example, a transformer for 10 kV in the primary circuit and 690 V in

the secondary circuit is required, then it must be ordered for a no-load ratio of 10 kV / 725 V.

The purpose of taps is to allow adjustment of the ratio to the actual line voltage. With a standard transformer, the

high-voltage winding has tap points equaling ± 2.5 %. These HV-taps can be adjusted by means of reconnectable

jumpers when the transformer is de-energized. Additional taps are available at extra cost on request.

Circuits and vector groups

The high-voltage and low-voltage windings of three-phase transformers can be star- or delta-connected. These

connection types are identified by the letters specified below (capital letters: high-voltage side, small letters: low-

voltage side):

· Y, y for star-connected windings

· D, d for delta-connected windings

In the vector group code for each transformer, these letters are followed by a digit. This states (in units of 30 degrees)

the phase angle j by which the voltages on the high-voltage side lead those on the low-voltage side. For example:

j = n * 30° where n = 1, 2, 3, ..., 11.

The vector groups of standard distribution transformers are normally Dy5 or Yy0 on which the neutrals are not

brought out.

1.3.2 Transformer types

Oil-immersed transformers or dry-type transformers (GEAFOL) are suitable to feed drive converters.

The oil-immersed transformer is generally cheaper to buy. However, in most cases, the transformer needs to be

installed outdoors. This transformer type can be installed indoors only if it can be directly accessed from outside.

Precautions must be taken to protect against fire and groundwater pollution. Although the transformer should ideally

be sited at the central power distribution point, this is often not possible.

The procurement costs for a GEAFOL transformer are higher. Due to its design, i.e. without fluid or combustible

insulating agents, it can be installed indoors and thus at the central power distribution point. It is often the most cost-

effective transformer type in installations with a relatively high energy density owing to its low losses and the fact that

no groundwater protection measures need be taken.

Transformers must be selected with a view to achieving the optimum cost effective solution for the entire plant, i.e. to

reduce investment and operating costs to a minimum. The following factors need to be considered:

· Procurement costs of transformers

· Required measures at installation site

· Operating costs incurred by losses, particularly in the distribution system

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1.3.3 Features of standard transformers and converter transformers

Converter transformers are specially designed for use with converters. They are specially built to withstand the

increased stresses associated with converter operation.

Differences between converter transformers and standard distribution transformers

· The windings of converter transformers are designed with increased insulation strength. This makes them

capable of withstanding the extreme voltage surges which can occur during converter commutation.

· The laminated core and winding are specially constructed, e.g. with small radial conductor depth on GEAFOL

transformers, so as to minimize stray losses caused by current harmonics.

· The transformers are mechanically designed to achieve low short-circuit forces on the one hand, and high short-

circuit strength on the other. The high thermal capacity of the transformers means that they are easily capable of

withstanding frequent surge loads up to 2.5 times rated output, such as those typical of main drives in rolling mill

applications.

· A pulse imbalance in the converter (e.g. caused by an interrupted firing pulse to a thyristor in the rectifier under

full power draw and the ensuing DC components in the line current) can cause damage to the core and

laminated moldings on GEAFOL transformers as a result of overheating. Monitoring the temperature of the tie-

rod inside the core is an effective method of eliminating this problem and does not damage the transformer.

It is evident from this description of the features of converter transformers that they are designed for relatively

extreme operating conditions of a kind not generally encountered with SINAMICS drives. For standard applications

where the transformer power is adjusted to suit the converter rated output, it is therefore permissible, even in the

case of unit transformers, to use normal distribution transformers instead of converter transformers.

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1.3.4 Three-winding transformers

Minimization of harmonic effects on the supply system is a frequent requirement associated with the operation of

high-power-output, variable-speed three-phase drive systems. This requirement can be met at relatively low cost

through a 12-pulse supply Infeed, particularly in cases where a new transformer needs to be installed anyway. In

such cases, a three-winding transformer must be selected. Three-winding transformers are basically designed as

converter transformers.

The basic operating principle of 12-pulse drive systems with two winding systems out of phase by 30° is explained in

section "Harmonic currents of 12-pulse rectifier circuits". The following remarks therefore refer solely to the

requirements of the three-winding transformer, the SINAMICS Infeed, and the supply system for the 12-pulse drive

system.

Operating principle of the 12-pulse drive system

Requirements of the three-winding transformer, the SINAMICS Infeed and the supply system

Requirements of the three-winding transformer and the SINAMICS Infeed

To achieve an optimum 12-pulse effect, i.e. the most effective possible elimination of current harmonics of the orders

h = 5, 7, 17, 19, 29, 31, ... on the high-voltage side of the transformer, the three-winding transformer design must be

as symmetrical as possible and suitable measures must also be taken to ensure that both of the low-voltage windings

are evenly loaded by the two 6-pulse rectifiers. Furthermore, no additional loads may be connected to only one of the

two low-voltage windings as this would hinder symmetrical loading of both windings. Furthermore, the connection of

more than one 12-pulse Infeed to a three-winding transformer should be avoided, particularly in systems which

feature Basic Line Modules equipped with thyristors that precharge the DC link by the phase angle control method.

Even current distribution is achieved by voltage drops (predominantly resistive) at:

· the secondary windings of the transformer

· the feeder cables between the transformer and rectifiers,

· the rectifier line reactors.

The requirements of the three-winding transformer, the feeder cable and the rectifier line reactors are therefore as

follows:

· Three-winding transformer must be symmetrical, recommended vector groups Dy5d0 or Dy11d0.

· Relative short-circuit voltage of three-winding transformer (per unit impedance) vk ≥ 4 %.

· Difference between relative short-circuit voltages of secondary windings Δvk ≤ 5 %.

· Difference between no-load voltages of secondary windings ΔV ≤ 0.5 %.

· Identical feeder cables, i.e. same type, same cross-section and same length.

· Use of line (commutating) reactors to improve current symmetry if applicable.

Generally speaking, double-tier transformers are the most suitable transformer type to satisfy the requirements

specified above for three-winding transformers for 12-pulse operation with SINAMICS.

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Requirements of the supply system

In addition to the requirements of the three-winding transformer and the SINAMICS Infeed, the supply system must

also meet certain standards with respect to the voltage harmonics present at the point of common coupling of the

three-winding transformer. This is because high voltage harmonics can (depending on their phase angle relative to

the fundamental wave) cause unwanted distortion of the time characteristics of the voltages of the two low-voltage

windings, potentially resulting in an extremely unbalanced current load on the transformer and the SINAMICS Infeed.

A pronounced 5th-order voltage harmonic can have the most critical impact, and also a strong 7th-order voltage

harmonic can have certain negative effects. By contrast, higher-order voltage harmonics do not have any significant

influence. Pronounced 5th and 7th-order harmonics can be caused, for example, by high-output 6-pulse loads (DC

motors, direct converters) that are supplied by the same medium-voltage system.

For this reason, the following information regarding the 5th-order voltage harmonic present at the point of common

coupling of the three-winding transformer must be taken into account.

- 5th-order voltage harmonic at the point of common coupling of the transformer ≤ 2 %:

Basic Line Modules (BLMs) and Smart Line Modules (SLMs) can be used as Infeeds for 12-pulse operation.

The 7.5 % current derating specified for 12-pulse operation with these Infeeds covers all possible current

imbalances that are caused by tolerances of the transformer, the SINAMICS Infeed and by the line voltage

harmonics.

- 5th-order voltage harmonic at the point of common coupling of the transformer > 2 %:

12-pulse operation under supply system conditions of this kind is not easily possible due to the potential for

severe imbalances. On the one hand the 7.5 % current derating specified for 12-pulse operation is no longer

sufficient to safely prevent overloading of the transformer and the Infeed. On the other hand, current

harmonics with the harmonic number h = 5, 7, 17, 19, 29, 31, etc. cannot be suppressed as required on the

high-voltage side of the transformer when the current is very unbalanced.

If a high 5th-order harmonic > 2 % is present in the voltage at the point of common coupling of the three-winding

transformer, the following solutions can be attempted:

- Reduce the harmonic content in the supply system using a harmonic compensation system (5th-order

harmonic < 2 %) and dimension the 12-pulse solution by applying the 7.5 % current derating mentioned

above

- Retain the high harmonic content in the voltage (5th-order harmonic > 2 %) and use a 12-pulse solution

subject to the following boundary conditions:

o Perform an analysis of the supply system in advance in order to identify the existing spectrum of

voltage harmonics, particularly the 5th-order harmonic

o Calculate the required and generally significantly higher current derating of up to 35 % depending

on the results of the supply system analysis and overdimension transformer and Infeed or

converter accordingly by up to 50 %

o Accept that the current harmonics with harmonic number h = 5, 7, 17, 19, 29, 31, etc. cannot be

fully compensated

- Use an Active Infeed with a two-winding transformer

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1.4 Harmonic effects on the supply system

1.4.1 General

The analysis presented in this section refers exclusively to low-frequency harmonic effects in the frequency range up

to 9 kHz. It does not take into account high-frequency harmonic effects as they relate to EMC (Electromagnetic

Compatibility) or radio frequency interference suppression. These high-frequency harmonic effects in the frequency

range from 150 kHz to 30 MHz are dealt with in the section "Line filters".

If electrical loads with non-linear characteristics are connected to a supply system with a sinusoidal voltage source

(generator, transformer), non-sinusoidal currents flow, which distort the voltage at the PCC (point of common

coupling). This influence on the line voltage caused by connecting non-linear loads is referred to as "harmonic effects

on the supply system" or "supply system perturbation".

The following diagram illustrates the correlation using the example of a low-voltage system which is supplied via a

transformer representing a purely sinusoidal voltage source and the internal resistance XTransformer. Loads with

various characteristics are connected to the PCC. The motors have a linear current-voltage characteristic and when

fed with purely sinusoidal voltage the currents drawn from the supply system are also purely sinusoidal. The

converters have a non-linear current-voltage characteristic because of the non-linear components in the rectifier

circuits (thyristors, diodes). Therefore the currents drawn from the supply system are non-sinusoidal in spite of the

supply with purely sinusoidal voltage. These non-sinusoidal currents, which are produced by the converters with non-

linear characteristic, cause non-sinusoidal voltage drops across the internal resistance of the transformer XTransformer

and therefore distort the voltage at the PCC.

Low-voltage system supplied via a transformer representing a purely sinusoidal voltage source

The non-sinusoidal quantities at the PCC (voltages and currents) can be divided into sinusoidal components, the

fundamental frequency component and the harmonic components. The higher the harmonic components of a

quantity are, the larger are the distortions of this quantity, i.e. the larger the deviations of this quantity from the

sinusoidal fundamental frequency.

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A useful factor for the resulting distortion of a quantity is the total harmonic distortion factor THD. It is defined as the

ratio between the rms value of the sum of all harmonic components and the rms value of the fundamental

component.

%100*

[%]

å÷

æ¥=

THD

Whereby:

Qis the considered electrical quantity (voltage V or current I)

his the order of the harmonic (harmonic frequency referred to line frequency)

Qh is the rms value of the harmonic component with harmonic number h

Q1is the rms value of the fundamental component (harmonic number 1)

As the individual devices and loads in a power supply system, such as generators, transformers, compensation

systems, converters, motors etc. are generally designed for operation on sinusoidal voltages they can be negatively

influenced or, in exceptional cases, even be destroyed by harmonic components that are too high. Therefore the

distortions of the voltages and currents by loads with non-linear characteristics must be limited.

For this purpose, limits are defined in the appropriate standards not only for the individual harmonics, but also for the

total harmonic distortion THD. Some standards specify limits for the voltage only (e.g. EN 61000-2-2 and EN 61000-

2-4), others for voltage and current (e.g. IEEE 519). These standards are discussed in more detail at the end of

section "Harmonic effects on supply system".

Because of the constantly increasing use of variable-speed drives, the evaluation of harmonic effects on the supply is

gaining in importance. The operators of supply systems as well as variable-speed drive users are demanding ever

more data about the harmonic response of the drives so that they can already check in the planning and

configuration phase whether the limits required by the standards are met.

This requires calculation of the harmonic load which results from the interaction between the connected loads on the

one hand and the transformer including its supply system on the other. The following data are therefore required to

calculate the harmonic currents and voltages exactly:

· Number of variable-speed drives on the supply system

· Shaft output at the operating point of the variable-speed drives

· Rectifier circuit type of the variable-speed drives

(e.g.: 6-pulse, 6-pulse with Line Harmonics Filter, 12-pulse)

· Data of the line (commutating) reactors of the variable-speed drives (relative short-circuit voltage vk)

· Transformer data (rated power, relative short-circuit voltage vk, rated voltages on the high-voltage and low-

voltage side)

· Data of the supply system which supplies the transformer (short-circuit power)

For most of the drives in the SINAMICS range, these calculations can be performed easily and exactly with the

"SIZER for Siemens Drives" configuration tool.

Note:

The calculated value for the total harmonic distortion of voltage THD(V) takes into account only the harmonics

caused by the relevant drives. Harmonics caused by other unknown electrical drives which are also connected to the

supply system or transformer in question are not included in the calculation. Consequently, the value calculated for

THD(V) should not be regarded as absolute, but as the value by which the total harmonic distortion factor THD(V) at

the PCC increases when the relevant drives are connected.

For many practical problems, an exact determination of all harmonic components of current and voltage is not

required and often an approximation of the expected harmonic currents is sufficient. These calculations are easy to

provide when the following generally valid relationships are clear:

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· The harmonic currents (harmonic numbers which occur and their amplitudes) are mainly determined by the

rectifier circuit type of the converter and are therefore device-specific. The transformer and the supply system for

the transformer have a relatively small effect on the harmonic currents. This means that when the rectifier circuit

type is known, the approximate magnitude of the harmonic currents is also defined and detailed information

about the transformer and the supply system are not required.

· The harmonic voltages (harmonic numbers which occur and amplitudes) are determined by the interaction

between the rectifier circuit of the converter and the transformer including the supply system. As they require

knowledge of the supply system and transformer data, these are system-specific and it is not therefore easy to

make general statements about their possible impact.

The following sections provide detailed information about the various types of rectifier circuits used with SINAMICS

and their harmonics currents.

It is assumed that there are no non-reactor-protected compensation systems in the line supply to which the variable-

speed drives are connected. When a supply system includes capacitors without reactor protection for reactive power

compensation, it is highly probable that resonances excited by the harmonics of the converters will occur at relatively

low frequencies. Therefore, it is strongly recommended that capacitors without reactor protection are not used in

supply systems loaded by converters and that all capacitors used in such constellations must have reactor protection.

1.4.2 Harmonic currents of 6-pulse rectifier circuits

1.4.2.1 SINAMICS G130, G150, S120 Basic Infeed and S120 Smart Infeed in motor operation

6-pulse rectifier circuits are line-commutated three-phase bridge circuits, which usually are equipped with thyristors or

diodes. They are used with SINAMICS G130 (thyristors), G150 (thyristors) and S120 Basic Line Modules (thyristors

for low power outputs and diodes for larger outputs). A line reactor with a relative short-circuit voltage of 2 % is

usually connected in series with these rectifiers.

With the rectifier / regenerative feedback units SINAMICS S120 Smart Line Modules which are equipped with IGBT

modules, the rectifier bridge for motor operation consists of the diodes integrated into the IGBT modules, so that a 6-

pulse diode bridge circuit is present during rectifier operation (motor operation). A line reactor with a relative short-

circuit voltage of 4 % is normally connected in series with the Smart Line Modules.

6-pulse three-phase bridge circuit with thyristors

With 6-pulse rectifier circuits, only odd harmonic currents and odd harmonic voltages that cannot be divided by 3

occur, with the following harmonic numbers h:

h = n * 6 ± 1 where n = 1, 2, 3, ...

i.e.

h = 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 35, 37, 41, 43, 47, 49, ...

The order of magnitude of the individual harmonic currents with the above harmonic numbers is mainly determined

by the 6-pulse rectifier circuit. However, the power supply inductance, which mainly consists of the inductance of the

supply transformer, and the inductance of the line reactor also have a certain effect. The larger these inductances

are, the better the line current is smoothed and the lower the harmonic currents are, especially the harmonic currents

with numbers 5 and 7.

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6-pulse rectifier with line reactor on a three-phase supply

Typical harmonic currents of a 6-pulse rectifier with a line reactor are specified in the following (relative short-circuit

voltage (per unit impedance) of the line reactor = 2 %).

These data are based on three supply system constellations with differences in line inductance or relative short-

circuit power RSC (RSC = Relative Short-Circuit Power in accordance with EN 60146-1-1: Ratio between the short-

circuit power SK Line of the supply system and the rated apparent power (fundamental apparent power) SConverter of the

converter at its point of common coupling PCC).

a) Supply system with low supply system inductance or high relative short-circuit power (RSC >> 50)

The short-circuit power Sk Line at the PCC is significantly higher than the apparent power of the connected

converters, i.e. only a relatively small percentage of the transformer load is attributable to the converter. This is

the case, for example, when a converter with an apparent power of << 100 kVA is connected to a supply system

which is supplied via a transformer with an apparent power of several MVA.

b) Supply system with average supply system inductance or average relative short-circuit power (RSC = 50)

This applies, for example, when approximately 30 % to 50 % of the transformer load is attributable to the

converter.

c) Supply system with high supply system inductance or low relative short-circuit power (RSC < 15)

This is the case when 100 % converter load is connected to a transformer with a high short-circuit voltage, i.e

only one converter whose apparent power approximately corresponds to the apparent power of the transformer.

Supply system with high relative short-circuit power (RSC >> 50): "Strong supply system"

h15711 13 17 19 23 25 THD(I)

100 % 45.8 % 21.7 % 7.6 % 4.6 % 3.4 % 1.9 % 1.9 % 1.1 % 51.7 %

Supply system with average relative short-circuit power (RSC = 50)

h15711 13 17 19 23 25 THD(I)

100 % 37.1 % 12.4 % 6.9 % 3.2 % 2.8 % 1.9 % 1.4 % 1.3 % 40.0 %

Supply system with low relative short-circuit power (RSC < 15) "Weak supply system"

h15711 13 17 19 23 25 THD(I)

100 % 22.4 % 7.0 % 3.1 % 2.5 % 1.3 % 1.0 % 0.8 % 0.7 % 23.8 %

Typical harmonic currents of 6-pulse rectifier with line reactors vk = 2 %

Spectral representation of the harmonic currents of a 6-pulse rectifier with line reactor vk = 2 % (specified in %)

- Bars on left: RSC >> 50

- Bars in center: RSC = 50

- Bars on right: RSC < 15

100

1357 9 11 13 15 17 19 21 23 25

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RSC >> 50

RSC = 50

RSC < 15

Typical line currents of a 6-pulse rectifier with line reactor vk = 2% as a function of the relative short-circuit power RSC

1.4.2.2 SINAMICS S120 Smart Infeed in regenerative operation

The SINAMICS S120 Smart Infeed is a rectifier / regenerative unit for four-quadrant operation and is equipped with

IGBT modules. On the line side a line reactor with a relative short-circuit voltage of 4 % is necessary. More detailed

information on the Smart Infeed can be found in the section “SINAMICS Infeeds and their properties” in the

subsection “Smart Infeed”. The following pages only deal with the harmonic effects of the Smart Infeed.

The rectifier bridge for rectifier operation (motor operation) consists of the diodes integrated into the IGBT modules so

that a 6-pulse diode bridge circuit is present in motor operation. All the information given in preceeding pages apply

here.

The bridge circuit for regenerative operation consists of the IGBTs which are connected anti-parallel to the diodes. So

this is also a 6-pulse bridge circuit, but the line currents in regenerative operation are slightly different from those in

motor operation and show slightly different harmonics.

Smart Line Module with diodes for motor operation and IGBTs for regenerative operation

In both, motor and regenerative operation, only odd harmonic currents and harmonic voltages that cannot be divided

by 3 occur, with the following harmonic order numbers h:

h = n * 6 ± 1 with n = 1, 2, 3, ...

i.e.

h = 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 35, 37, 41, 43, 47, 49, ...

The following table shows the typical current harmonics in motor and regenerative operation with a reactor on the line

side (relative short-circuit voltage of the line reactor = 4 %)

For this a supply system constellation with an average supply inductance and an average relative short-circuit power

of RSC = 50 has been taken as a basis for the calculations.

Current harmonics in rectifier operation (motor operation)

h1 5 7 11 13 17 19 23 25 THD(I)

100 % 30.6 % 8.6 % 5.7 % 3.1 % 2.1 % 1.6 % 1.2 % 1.1 % 32.6 %

Current harmonics in regenerative operation

h1 5 7 11 13 17 19 23 25 THD(I)

100 % 20 % 16 % 11 % 8 % 7 % 6 % 5 % 4 % 32 %

Typical current harmonic values for the SINAMICS Smart Infeed in rectifier (motor) operation and regenerative operation

with a line reactor of 4 %

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Typical current harmonic spectrum with Smart Infeed in Typical current harmonic spectrum with Smart Infeed in

rectifier (motor) operation with a line reactor of 4 % regenerative operation with a line reactor of 4 %

(specified in %) (specified in %)

The 5

th current harmonic, which is very strong in rectifier (motor) operation, is reduced considerably during

regenerative operation. Therefore all remaining harmonics increase slightly. Due to the considerable decrease in the

5th current harmonic, there is a slightly lower Total Harmonic Distortion factor THD(I) in regenerative operation. So it

is sufficient for harmonics calculations with the SINAMICS Smart Infeed to consider only the worse rectifier (motor)

operation.

The following diagrams show the typical line side currents with SINAMICS Smart Infeed in rectifier (motor) operation

and regenerative operation.

Typical line current with Smart Infeed in rectifier operation Typical line current with Smart Infeed in regenerative

operation

1.4.3 Harmonic currents of 6-pulse rectifier circuits with Line Harmonics Filter

Line Harmonics Filter LHF are passive filters that mainly absorbe the 5th and the 7th harmonic in the line current of 6-

pulse rectifiers and in this way significantly reduce the harmonic effects on the supply. Two versions of Line

Harmonics Filter are available, i.e. LHF and LHF compact. They are installed between the mains supply and

converter and can be used with SINAMICS G130 and G150 units. When stand-alone Line Harmonics Filters (LHF)

are used, a line reactor with a relative short-circuit voltage of vk = 2 % must be installed at the converter input. For

Line Harmonics Filters compact (LHF compact) there is no need to install a line reactor. For further information about

the operating principle and boundary conditions relating to the use of Line Harmonics Filters, please refer to section

"Line Harmonics Filters (LHF or LHF compact)". This section of the manual will only discuss the harmonic

characteristics of the LHF and LHF compact filters.

6-pulse rectifier with line reactor and Line Harmonics Filter (LHF or LHF compact) on a three-phase supply

100

1 3 5 7 9 11 13 15 17 19 21 23 25 0

100

1 3 5 7 9 11 13 15 17 19 21 23 25

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Line Harmonics Filters LHF influence only the magnitude of the harmonic currents, but not their spectrum. As a

consequence, therefore, the 6-pulse rectifier causes odd harmonic currents and voltages that cannot be divided by 3

despite the use of a Line Harmonics Filter. The harmonic numbers h are as follows:

h = n * 6 ± 1 where n = 1, 2, 3, ...

i.e.

h = 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 35, 37, 41, 43, 47, 49, ...

Even when Line Harmonics Filters (LHF or LHF compact) are used, the supply system inductance has a certain

effect on the magnitude of the harmonic currents, but this is significantly lower than with 6-pulse rectifiers without Line

Harmonics Filters.

The typical harmonic currents of 6-pulse rectifiers with Line Harmonics Filters (LHF or LHF compact) are specified

below.

These data again are based on three different supply system constellations with differences in supply system

inductance or relative short-circuit power RSC.

a) Supply system with low supply system inductance or high relative short-circuit power (RSC >> 50)

The short-circuit power Sk Line at the PCC is significantly higher than the apparent power of the connected

converters, i.e. only a relatively small percentage of the transformer load is attributable to the converter.

b) Supply system with average supply system inductance or average relative short-circuit power (RSC = 50)

This applies, for example, when approximately 30 % to 50 % of the transformer load is attributable to the

converter.

c) Supply system with high supply system inductance or low relative short-circuit power (RSC < 15)

This is the case when 100 % converter load is connected to a transformer with a high short-circuit voltage, i.e

only one converter whose apparent power approximately corresponds to the apparent power of the transformer.

Supply system with high relative short-circuit power (RSC >> 50): "Strong supply system“

h1 5 7 11 13 17 19 23 25 THD(I)

100 % 4.5 % 4.7 % 2.8 % 1.6 % 1.2 % 0.9 % 0.6 % 0.5 % 7.5 %

Supply system with average relative short-circuit power (RSC = 50)

h1 5 7 11 13 17 19 23 25 THD(I)

100 % 4.2 % 4.4 % 2.6 % 1.4 % 1.2 % 0.8 % 0.6 % 0.5 % 7.0 %

Supply system with low relative short-circuit power (RSC < 15): "Weak supply system“

h1 5 7 11 13 17 19 23 25 THD(I)

100 % 2.9 % 3.1 % 1.8 % 1.3 % 1.1 % 0.7 % 0.6 % 0.5 % 5.0 %

Typical harmonic currents of 6-pulse rectifiers with Line Harmonics Filters LHF

Spectral representation of the harmonic currents of 6-pulse rectifiers with Line Harmonics Filters (specified in %)

- Bars on left: RSC >> 50

- Bars in center: RSC = 50

- Bars on right: RSC < 15

100

1 3 5 7 9 11 13 15 17 19 21 23 25

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Typical line current of 6-pulse rectifiers with LHF or LHF compact

When 6-pulse rectifier circuits (G130, G150) with Line Harmonics Filters (LHF or LHF compact) are used, the system

complies with the limit values of standard IEEE 519 (Recommended Practice and Requirements for Harmonic Control

in Electrical Power Systems) on the condition: Relative short-circuit voltage of the supply system (per unit

impedance) vk ≤ 5 % or relative short-circuit power of the supply system RSC ≥ 20.

1.4.4 Harmonic currents of 12-pulse rectifier circuits

A 12-pulse rectifier circuit is created when two identical 6-pulse rectifiers are supplied from two different supply

systems, whose voltages are out of phase by 30°. This is achieved with the use of a three-winding transformer,

whose one low-voltage winding is star-connected and the other delta-connected. The harmonic effects can be

significantly reduced with 12-pulse circuits as compared to 6-pulse circuits. 12-pulse rectifier circuits can be

implemented for SINAMICS G150 in the higher power range, which consists of the parallel connection of two

individual G150 devices and therefore two 6-pulse rectifiers. 12-pulse rectifier circuits can also be implemented by

using two S120 Basic Line Modules or S120 Smart Line Modules.

12-pulse rectifier with separate three-winding transformer

Due to the phase shifting of 30° between the two secondary voltages, the harmonic currents with harmonic numbers

h = 5, 7, 17, 19, 29, 31, 41, 43, ... , which are still present in the input currents of the 6-pulse rectifiers, compensate

one another so that theoretically only odd harmonic currents and voltages that cannot be divided by 3 with the

following numbers h occur at the PCC on the primary side of the three-winding transformer:

h = n * 12 ± 1 where n = 1, 2, 3, ...

i.e.

h = 11, 13, 23, 25, 35, 37, 47, 49, ...

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However, as in practice there is never a perfectly symmetrical load distribution between the two rectifiers, it must be

assumed that harmonic currents with harmonic numbers h = 5, 7, 17, 19, 29, 31, 41, 43, …… are also present with

12-pulse circuits, but with amplitudes that are maximum 10 % of the corresponding values of 6-pulse circuits.

The typical harmonic currents of 12-pulse rectifier circuits are specified below.

As these are generally only used with high-power ratings, it can be assumed that converters with a 12-pulse rectifier

circuit are operated on a separate three-winding transformer and line reactors are dispensed with. This constellation

corresponds to a supply system with a low to medium relative short-circuit power RSC = 15 to 25.

Supply system with low to medium relative short-circuit power (RSC = 15 ... 25): "Weak supply system"

h1 5 7 11 13 17 19 23 25 THD(I)

100 % 3.7 % 1.2 % 6.9 % 3.2 % 0.3 % 0.2 % 1.4 % 1.3 % 8.8 %

Harmonic currents of 12-pulse rectifier circuits with separate three-winding transformer without line reactor

Spectral representation of the harmonic currents of 12-pulse rectifier circuits

without line reactor (specified in %)

1.4.5 Harmonic currents and harmonic voltages of Active Infeeds (AFE technology)

The SINAMICS Active Infeed is a self-commutated, PWM IGBT inverter (Active Line Module ALM) which produces a

constant, stabilized DC link voltage from the three-phase line voltage. Thanks to the Clean Power Filter (Active

Interface Module AIM) installed between the power supply and IGBT inverter, the power drawn from the supply is

near-to-perfect sinusoidal. The Active Infeed is ideally suited for 4Q operation, i.e. it has both infeed and regenerative

feedback capability.

The Active Infeed is the highest grade Infeed variant for SINAMICS. It is used in SINAMICS S150 cabinets and as

S120 Active Infeed.

Active Infeed (PWM IGBT inverter with Clean Power Filter) on a three-phase supply system

The harmonic effects on the supply system associated with the Active Infeed are very low due to the combination of

Clean Power Filter and the IGBT inverter which is clocked with a pulse frequency of a few kHz.

100

13579 11 13 15 17 19 21 23 25

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The following diagrams show the typical harmonic currents Ih and harmonic voltages Vh associated with the Active

Infeed. The fundamental frequencies I1and V1, which equal 100 % in each case, are masked out.

Spectral representation of typical harmonic currents I h in the line current of the Active Infeed

(specified in % referred to the rated current of the Active Infeed)

Spectral representation of typical harmonic voltages V h in the line voltage of the Active Infeed

(specified in % referred to the rated voltage of the Active Infeed)

In contrast to 6-pulse and 12-pulse rectifier circuits, the harmonics associated with the Active Infeed are both even

and odd. The extent to which harmonics are dependent on supply system conditions is relatively small which means

that the harmonic spectra in the diagrams can be regarded as representative of all typical supply conditions. The

majority of current and voltage harmonics is typically significantly lower than 1 % of rated current or rated voltage with

the Active Infeed. Please note that the scale of representation is different to the scale used for the harmonic spectra

of the 6-pulse and 12-pulse rectifier circuits discussed above.

The total distortion factors of current THD(I) and voltage THD(V) are given in the following table and demonstrate

only a slight dependence on supply system conditions.

Total distortion factor current

THD(I)

Total distortion factor voltage

THD(V)

Supply system with high relative short-

circuit power (RSC >> 50):

"Strong supply system"

< 4.1 % < 1.8 %

Supply system with average relative short-

circuit power (RSC = 50) < 3.0 % < 2.1 %

Supply system with low relative short-

circuit

power (RSC = 15)

"Weak supply system"

< 2.6 % < 2.3 %

Total distortion factors THD(I) and THD(V) with Active Infeed as a function of the system short-circuit power

When self-commutated IGBT Infeeds (S150, S120 Active Line Modules) are used, the system complies with the limit

values stipulated in standard IEEE 519 (Recommended Practices and Requirements for Harmonic Control in

Electrical Power Systems).

Harmonic number h

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1.4.6 Standards and permissible harmonics

A number of key standards which define the permissible limit values for harmonics are listed below.

EN 61000-2-2

Compatibility Levels for Low-Frequency Conducted Disturbances and Signaling in Public Low-Voltage Power

Supply Systems

This European standard deals with conducted disturbance variables in the frequency range from 0 Hz to 9 kHz. It

specifies the compatibility levels for low-voltage AC supply systems with a rated voltage of up to 420 V 1-phase, or

690 V 3-phase and a rated frequency of 50 Hz or 60 Hz.

The compatibility levels specified in this standard are valid for the PCC (Point of Common Coupling) with the public

supply system.

Limits for harmonic currents are not defined. Limits are specified only for harmonic voltages and the total harmonic

distortion of the voltage THD(V).

The limits for the PCC with the public supply system are identical to the limits of Class 2 according to EN 61000-2-4

(see below).

The corresponding compatibility level for the total harmonic distortion THD(V) is 8 %.

EN 61000-2-4

Compatibility Levels for Low-Frequency Conducted Disturbances in Industrial Plants

This European standard deals with conducted disturbance variables in the frequency range from 0 Hz to 9 kHz. It

specifies compatibility levels in numbers for industrial and private supply systems with rated voltages up to 35 kV and

a rated frequency of 50 Hz or 60 Hz.

Supply systems on ships, aircraft, offshore platforms and railways are not in the field of application of this standard.

EN 61000-2-4 defines three electromagnetic environmental classes:

Class 1 This class applies to protected supplies and has compatibility levels that are lower than the level of the

public supply system. It refers to equipment that is very sensitive to disturbance variables in the power

supply, e.g. electrical equipment of technical laboratories, certain automation and protection equipment,

certain data processing equipment etc.

Class 2 This class generally applies to PCCs (Points of Common Coupling) with the public supply system and to

IPCs (Internal Points of Coupling) with industrial or other private supply systems. The compatibility

levels for this class are generally identical to those for public supply systems. Therefore components

that have been developed for operation on public supply systems can be used in this industrial

environment class.

Class 3 This class applies only to IPCs (Internal Points of Coupling) in industrial environments. It has higher

compatibility levels for some disturbance variables than Class 2. For example, this class should be

considered when one of the following conditions applies:

· The main part of the load is supplied via converters;

· Welding machines are used;

· Large motors are started frequently;

· Loads vary quickly.

The class that is to be used for new plants or expansions to existing plants cannot be defined in advance, but

depends on the intended type of installation (of equipment, device) and the process.

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EN 61000-2-4 does not define limits for harmonic currents. Limits are specified only for harmonic voltages and the

total harmonic distortion of the voltage THD(V).

Harmonic number

Class 1

Class 2

Class 3

5 3 6 8

7 3 5 7

11 3 3.5 5

13 3 3 4.5

17 2 2 4

17 < h ≤ 49 2.27 x (17/h) – 0.27 2.27 x (17/h) – 0.27 4.5 x (17/h) - 0.5

Compatibility levels for harmonics

– harmonic contents of the voltage V, odd harmonics, no multiples of 3

Class 1 Class 2 Class 3

Total Harmonic Distortion factor

THD(V)

5 % 8 % 10 %

Compatibility levels for the Total Harmonic Distortion factor of the voltage THD(V)

The following is a rough guide to the supplementary conditions under which the limits stipulated in EN 61000-2-4 can

be maintained under typical supply system conditions (RSC > 10 or vk Line < 10 %):

· When using 6-pulse rectifier circuits (G130, G150, S120 Basic Line Modules and S120 Smart Line Modules), the

limits of Class 2 can typically be maintained when 30 % to maximum 50 % of the total transformer load is made

up of converter load. Compliance with the limit values of Class 3 is typically possible under typical supply

conditions even with virtually 100 % converter loading.

· When using 6-pulse rectifier circuits (G130, G150) with Line Harmonics Filters (LHF and LHF compact), the limits

of Class 2 can be maintained irrespective of what percentage of the total transformer load is attributable to the

converter.

· When using 12-pulse rectifier circuits (G150 in the higher power range with two parallel connected converters or

S120 Basic Line Modules or S120 Smart Line Modules supplied by a three-winding transformer), the limits of

Class 2 can also be maintained.

· When self-commutated IGBT infeeds (S150, S120 Active Line Modules) are used, the limits of Class 2 can be

maintained.

If a large number of 6-pulse rectifier circuits are used, an exact calculation of the harmonic effects on the supply

should always be performed with the supplementary conditions of the individual plant configuration.

SINAMICS converters and the corresponding line-side system components (line reactors, Line Harmonics Filter and

line filters) are designed for being connected to supplies with a continuous level of voltage harmonics, according to

EN 61000-2-4, Class 3. In the short-term (< 15 s within a time period of 2.5 min) a level of 1.5 times the continuous

level is permissible.

That means that no voltage harmonics higher than those given in the table under Class 3 may appear at the

connection point for SINAMICS units. This includes harmonics produced by the units themselves. This must be

guaranteed by means of correct engineering. If necessary, Line Harmonics Filters, 12-pulse solutions or Active

Infeeds may be used to stay within the limits of Class 3.

The values according to EN 61000-2-4, Class 3, must be observed not only for the protection of other equipment

connected to the PCC, but also for the protection of the SINAMICS units themselves. Otherwise, components in the

converter itself or the corresponding line-side components may be thermically overloaded or error functions may

occur in the converter.

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IEEE 519 - 2014

IEEE Recommended Practice and Requirements for Harmonic Control in Electrical Power Systems

This standard is valid in the USA, Canada and in large parts of Asia. It specifies limits for harmonic voltages and

currents for the sum of all loads at the PCC (Point of Common Coupling).

Permissible voltage harmonics for integer multiples of the fundamental wave and permissible THD(V) (Total

Harmonic Distortion of voltage) at the point of common coupling PCC

Nominal line voltage VLine

at the PCC

Permissible value for each individual

voltage harmonic

Permissible value for the total harmonic

distortion THD(V) of voltage

Line

≤ 1.0 kV 5 % 8 %

Permissible integer multiple voltage harmonics at the PCC and permissible THD(V) value at the PCC

The THD(V) (Total Harmonic Distortion of voltage) is defined as the ratio between the rms value of the sum of all

harmonic voltages up to the 50th-order harmonic and the rms value of the fundamental wave of the voltage.

%100*

)[%](

å÷

VTHD

Key to equation:

hharmonic number of the harmonic at the PCC

Uh rms value of the harmonic voltage at the PCC with harmonic number h

U1rms value of the fundamental wave of the voltage at the PCC (harmonic number 1)

Permissible current harmonics for odd1 multiples of the fundamental wave and permissible TDD (Total

Demand Distortion) of the current at the point of common coupling PCC

The limit values depend on the ratio between the maximum short-circuit current at the point of common coupling PCC

and the fundamental wave of the maximum demand load current at the point of common coupling PCC under normal

operating conditions according to the following table:

Ratio of maximum

short-circuit current

and maximum demand

load current at PCC

3 ≤ h < 11 11 ≤ h < 17 17 ≤ h < 23 23 ≤ h < 35 35 ≤ h ≤ 50

Total Demand

Distortion

TDD

< 20 4 % 2.0 % 1.5 % 0.6 % 0.3 % 5 %

20 < 50 7 % 3.5 % 2.5 % 1.0 % 0.5 % 8 %

50 < 100 10 % 4.5 % 4.0 % 1.5 % 0.7 % 12 %

100 < 1000 12 % 5.5 % 5.0 % 2.0 % 1.0 % 15 %

> 1000 15 % 7.0 % 6.0 % 2.5 % 1.4 % 20 %

Permissible odd1 current harmonics referred to the fundamental wave of the maximum demand load current at the PCC

and permissible current TDD value at the PCC

1Even current harmonic limit values equal 25 % of the odd current harmonic limit values specified above

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The TDD (Total Demand Distortion) of the current is defined as the ratio between the rms value of the sum of all

harmonic currents up to the 50th-order harmonic and the rms value of the fundamental wave of the maximum

demand load current.

%100*

[%]

å÷

TDD

Key to equation:

hharmonic number of the harmonic at the PCC

Ihrms value of the harmonic current at the PCC with harmonic number h

I1rms value of the fundamental wave of the maximum demand load current at the PCC (harmonic number 1)

Note:

By contrast with the THD where the harmonics of the physical quantity under consideration are referred to the

relevant fundamental wave, IEEE 519 states for the TDD that the harmonic currents at the PCC are referred to the

fundamental wave of the maximum demand load current at the PCC.

The maximum demand load current at the PCC is defined as the sum of the currents corresponding to the maximum

demand during each of the twelve previous months divided by 12.

The following is a rough guide to the boundary conditions under which the limits according to IEEE 519 can be

maintained under typical supply system conditions:

· When using 6-pulse rectifier circuits (G130, G150, S120 Basic Line Modules and S120 Smart Line Modules), the

limits can generally be maintained only if a very low percentage of the total transformer load is made up of

converter load. Typical constellations with 6-pulse rectifiers cannot maintain the limits due to excessive harmonic

currents with harmonic numbers 5, 7, 11 and 13.

· When 6-pulse rectifier circuits (G130, G150) with Line Harmonics Filters (LHF and LHF compact) are used,

compliance with the limit values is possible on the condition: Relative short-circuit voltage of the supply system

(per unit impedance) vk ≤ 5 % or relative short-circuit power of the supply system RSC ≥ 20.

· When using 12-pulse rectifier circuits (G150 in the higher power range with two parallel connected converters,

S120 Basic Line Modules or S120 Smart Line Modules supplied by a three-winding transformer) the limits can

only be maintained with a relatively strong supply and, correspondingly, a large relative short-circuit power.

Configurations with 12-pulse rectifier circuits connected to weak supplies with small relative short-circuit power

do not maintain the limits due to high harmonic currents with the harmonic numbers 11 and 13.

· When self-commutated IGBT rectifiers / regenerative units (S150, S120 Active Line Modules) are used, the limits

can always be maintained.

If 6-pulse rectifier circuits without Line Harmonics Filters or 12-pulse rectifier circuits are used, an exact calculation of

the harmonic effects on the supply should always be performed with the supplementary conditions of the individual

plant configuration.

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1.5 Line-side reactors and filters

1.5.1 Line reactors (line commutating reactors)

Converters with 6-pulse or 12-pulse rectifier circuits (G130, G150, S120 Basic Line Modules and S120 Smart Line

Modules) always require line reactors if

· they are connected to a supply system with high short-circuit power, i.e. with low impedance,

· more than one converter is connected to the same point of common coupling (PCC),

· converters are equipped with line filters for RFI suppression,

· G130/G150 converters are equipped with Line Harmonics Filters (LHF) to reduce the effects of harmonics

on the supply system (does not apply to Line Harmonics Filters LHF compact),

· converters are operating in parallel to increase the output power (G150 parallel converters and converters

with a parallel connection of S120 Basic Line Modules or S120 Smart Line Modules).

For the converters G130 and G150 as well as for S120 Basic Line Modules line reactors with a relative short-circuit

voltage of vk = 2 % are available. The S120 Smart Line Modules require line reactors with a relative short-circuit

voltage of vk = 4 %.

Supply systems with high short-circuit power

The line reactor smoothes the current drawn by the converter and thus reduces harmonic components in the line

current. The use of a line reactor in conjunction with the SINAMICS devices described in this engineering manual can

reduce the 5th harmonic by approximately 5 to 10 %, and the 7th by approximately 2 to 4 %. The harmonics with

higher harmonic numbers are not significantly affected by a line reactor. As a result of the reduced harmonic currents

the thermal loading on the power components in the rectifier and the DC link capacitors is reduced. The harmonic

effects on the supply are also reduced, i.e. both, the harmonic currents and harmonic voltages in the line supply are

attenuated.

Typical line current of a 6-pulse rectifier circuit without and with use of a line reactor

The installation of line reactors can be dispensed with only if the line inductance is sufficiencly high resp. the relative

short-circuit power RSC at the point of common coupling PCC is sufficiently low. The relevant applicable values are

unit-specific and therefore given in the chapters on specific unit types. A definition and explanation of the term

"relative short-circuit power" can be found in the section "Supply systems and supply system types".

More than one converter connected to the same point of common coupling

Line reactors must always be provided if more than one converter is connected to the same point of common

coupling. In this instance, the reactors perform two functions, i.e. they smooth the line current and decouple the

rectifiers at the line side. This decoupling is an essential prerequisite for correct operation of the rectifier circuit,

particularly in the case of SINAMICS G130 and G150. For this reason, each converter must be provided with its own

line reactor, i.e. it is not permissible for a single line reactor to be shared among converters.

Converters with line filters or Line Harmonics Filters (LHF)

A line reactor must also be installed for any converter that is to be equipped with a line filter for RFI suppression or

with a Line Harmonics Filter (LHF) to reduce harmonic effects on the supply. This is because filters of this type

cannot be 100% effective without a line reactor (does not apply to Line Harmonics Filters LHF compact). In this case,

the line reactor must be installed between the line filter or LHF and the converter input.

Converters connected in parallel

Another constellation which requires the use of line reactors is the parallel connection of converters where the

paralleled rectifiers are directly connected at both the line side and the DC link side. This applies to both G150

paralleled units and to parallel connections of S120 Basic Line Modules and S120 Smart Line Modules if these

involve a 6-pulse connection. The line reactors provide for balanced current distribution and ensure that no individual

rectifier is overloaded by excessive current imbalances.

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Permissible cable length between line reactor and converter

Line reactors should be positioned directly at the converter input whenever possible. In individual cases, however, the

low frequencies involved make it possible to situate the line reactor at a greater distance from the converter, provided

that the cable length does not exceed 100 m. Exception: Converters with optional line filters for category C2 in

accordance with EN 61800-3 require the line reactor and line filter to be positioned directly at the converter input (see

also section "Line filters").

1.5.2 Line Harmonics Filters (LHF and LHF compact)

1.5.2.1 Operating principle of Line Harmonics Filters (LHF and LHF compact)

Line Harmonics Filters (LHF and LHF compact) are passive LC filters that mainly filter out the 5th and the 7th

harmonics in the line current of 6-pulse rectifiers and in this way significantly reduce the harmonic effects at the PCC.

Compliance with the limit values defined in standard EN 61000-2-4 / Class 2 and the very low limit values defined in

standard IEEE 519 (Recommended Practice and Requirements for Harmonic Control in Electrical Power Systems) is

therefore assured on the condition: Relative short-circuit voltage of the supply system (per unit impedance) vk ≤ 5 %

or relative short-circuit power of the supply system RSC ≥ 20.

Two versions of Line Harmonics Filters are available, i.e. LHF and LHF compact. They can be used for

SINAMICS G130 units (LHF only) and G150 units (LHF and LHF compact). They are installed between the supply

system and the converter. Line Harmonics Filters (LHF) form an oscillating circuit at the converter side together with

the line reactor of the converter which must be installed between the LHF and the converter input, and they form an

oscillating circuit at the line side together with the supply inductance. There is no need to install a line reactor at the

converter input for Line Harmonics Filters compact (LHF compact).

The oscillating circuit on the converter side consists of the Line Harmonics Filter and the line reactor at the

converter input with a relative short-circuit voltage vk = 2 % (not applicable to LHF compact). This oscillating circuit

should, as far as possible, absorbe the current harmonics produced by the converter and should, therefore, prevent

these harmonics from successfully entering the supply. Its resonant frequency is therefore designed for the largest

harmonic, i.e. the 5th, so that the 5th current harmonic of the converter is almost completely absorbed by the filter. The

7th current harmonic of the converter is also absorbed significantly and even the 11th and the 13th are partly

absorbed. In the following diagram, the solid, black line shows the filter characteristics on the converter side. It is a

measure of how much each individual harmonic produced by the converter will be reduced by the LHF and also of

how much the power supply will consequently get rid of the harmonics.

Schematic diagram of the Line Harmonic Filter and the converter-side / line-side filter characteristics (qualitative analysis)

The spectrum diagrams illustrate the typical harmonic currents, both at the converter side where they are produced,

and at the line side after the Line Harmonics Filter (LHF or LHF compact) has reduced them according to its

converter-side filter characteristics. Further information on the harmonic currents of Line Harmonics Filter can be

found in the section “Harmonic effects on the supply system”.

a) Typical spectrum of the harmonic currents on the

converter side (specified in %)

b) Typical spectrum of the harmonic currents on the line

side after filtering (specified in %)

100

135 7 9 11 13 15 17 19 21 23 25

100

135 7 9 11 13 15 17 19 21 23 25

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The oscillating circuit on the line side consists of the Line Harmonics Filter and the supply inductance. It inevitably

results from the electrical filter design and basically also absorbes harmonics present in the supply. This behaviour is,

however, highly undesirable because the Line Harmonics Filter, as a component associated to the converter, should

only absorbe harmonics on the converter side and not those on the line side. As the oscillating circuit on the line side

is unavoidable, it is dimensioned in such a way that the line-side filter effect is as low as possible. This behaviour is

achieved by dimensioning the line-side oscillating circuit differently from the converter-side oscillating circuit and

coordinating the resonant frequency of the line-side circuit with the 3rd harmonic. This harmonic is virtually non-

existant in three-phase supply systems and thus the filter is almost completely without load at its resonant frequency.

The 5th and 7th harmonics are absorbed on the line side, but on a much smaller scale than on the converter side. The

blue, dashed curve in the diagram on the previous page shows the line-side filter characteristics, which is a measure

how much the harmonics present in the supply, are absorbed. For the harmonics relevant in supply systems with 6-

pulse rectifier circuits with the harmonic numbers of h = 5, 7, 11, 13, 17, 19, …… the blue curve is considerably lower

than the black curve so that the filter, as desired, almost entirely absorbes the converter-side harmonics but only a

small amount of the line-side harmonics present in the supply. Therefore, the LHF primarily filters the converter and

not the supply. An overload of the Line Harmonics Filter caused by the harmonics in the supply is not possible as

long as the harmonic content of the supply is lower than the limit values according to EN 61000-2-4, Class 3, which

allows a Total Harmonic Distortion factor in the voltage of THD(V) < 10 % in relatively harsh industrial environments.

Details can be found in the section “Harmonic effects on the supply system”, under the subsection “Standards and

pemissible harmonics”.

Converter efficiency with Line Harmonics Filters

Line Harmonics Filters produce losses which impair the efficiency of the converter. When Line Harmonics Filters LHF

and LHF compact are used on SINAMICS G130 / G150 converters, the converter efficiency typically drops by about

1 % from 98 % to 97 %. The steep reduction in the harmonics as compared to 6-pulse converters without Line

Harmonics Filter therefore goes hand in hand with a relatively minor drop in efficiency.

In order to reduce the harmonics on the supply, SINAMICS S150 converters with a pulsed Active Infeed can basically

be used as an alternative to Sinamics G130 / G150 with Line Harmonics Filters LHF and LHF compact. While the

harmonics at the line side are slightly more reduced with the S150, however, these converters are also less efficient

at typically 96 %, so that this alternative solution cannot be recommended from the energy point of view.

The boundary conditions which must be considered for use of the two variants of Line Harmonics Filters are

described in detail below:

· Line Harmonics Filter (LHF) with separate housing (6SL3000-0J_ _ _-_AA0).

· Line Harmonics Filter compact (LHF compact) as option L01 for SINAMICS G150 cabinet units.

1.5.2.2 Line Harmonics Filter (LHF) with separate housing (6SL3000-0J_ _ _-_AA0)

Line Harmonics Filters (LHF) are stand-alone filters in a separate housing with degree of protection IP21 which can

be operated in combination with SINAMICS G130 Chassis units and SINAMICS G150 converter cabinet units and

which are installed between the low-voltage distribution panel in the plant and the SINAMICS converter.

Preconditions for using these Line Harmonics Filters (LHF) are:

· A line-side fuse protection for the LHF

· A main contactor or a circuit breaker on the converter side

· A converter-side line reactor with a relative short-circuit voltage of 2 %

Additional components required in conjunction with stand-alone Line Harmonics Filters (LHF)

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The following points must also be noted:

Each converter must have its own LHF. It is not permissible to operate more than one low-power converter on a

single high-power LHF.

The power rating of the converter must not be less than two grades lower than that of the Line Harmonics Filter LHF.

Otherwise the mismatching of the line reactors will influence the resonance frequency on the converter side too

much, thereby reducing the effectiveness of the filter. With this in mind, Line Harmonics Filters are available for the

following converter output power ratings:

Supply voltage Rated converter power

380 V – 480 V 3AC ≥ 160 kW

500 V – 600 V 3AC ≥ 110 kW

660 V – 690 V 3AC ≥ 160 kW

The relative short circuit power RSC of the supply system must have a value of at least 10. If the short circuit power

is any smaller, the line-side resonance frequency will be affected too much and the fundamental wave of the line

voltage may increase considerably until it reaches values beyond the permissible line voltage tolerance of the

converter.

Line-side fuse protection for the Line Harmonics Filters should be implemented using the same fuse types as those

recommended in Catalog D 11 as line-side power components for protecting the corresponding converters.

If line-side switches or contactors are used for switching on/off a Line Harmonics Filter, these must be dimensioned

for the making current involved, which is in the same order of magnitude as the rated current. For this reason,

contactors from utilization category AC-1 (switching of resistive loads) can be used.

The converter-side main contactor or the converter-side circuit breaker must not connect the converter to the filter,

before the filter is connected to the supply. When shutting down the system, the converter must always be

disconnected from the filter by means of the main contactor or the circuit breaker, before the filter is disconnected

from the supply.

Line Harmonics Filters can be connected in parallel in order to increase the power. A current derating of 7.5 % must

be taken into account.

Line Harmonics Filters LHF can also be used with G150 parallel converters (G150 power extension), if a 6-pulse

power supply is given and both partial converters are fed from the same supply resp. the same transformer winding.

In this case, each partial converter must be connected to a Line Harmonics Filter on the line side, which is adapted to

the power of the partial converter.

With a 12-pulse line connection, the use of a Line Harmonics Filter does not make technical sense because no

additional improvement of the harmonic effects will be achieved.

LHFs can be used at ambient temperatures of > 40 °C to maximum 50 °C. Current derating of 2 % per °C must be

applied at ambient temperatures of > 40 °C.

Line Harmonics Filter LHF can be operated on both, 50 Hz and 60 Hz supply systems. The supply frequency is

selected through reconnection of jumper links in the filter at the commissioning stage. The supply frequency is set for

50 Hz in the delivery state (factory setting).

LHFs can be connected to the following supply systems:

Line supply voltage / line frequency

380 V – 415 V 3AC ±10% / 50 Hz, changeable to

440 V – 480 V 3AC ±10% / 60 Hz

500 V – 600 V 3AC ±10% / 50 Hz, changeable to

500 V – 600 V 3AC ±10% / 60Hz

660 V – 690 V 3AC ±10% / 50 Hz, changeable to

660 V – 690 V 3AC ±10% / 60 Hz

Line Harmonics Filters LHF can be used in grounded (TN/TT) and non-grounded (IT) supply systems.

Line Harmonics Filters should not be operated on supply systems with reactive current compensation systems, nor in

combination with other 6-pulse converters that are not equipped with Line Harmonics Filters, nor in combination with

devices that operate with pronounced phase angle control.

Line Harmonics Filters LHF should be positioned directly at the converter input whenever possible. In individual

cases, however, the low frequencies involved make it possible to locate the Line Harmonics Filter at a greater

distance from the converter, although the cable length should not exceed 100 m.

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1.5.2.3 Line Harmonics Filter compact (LHF compact) as Option L01 for SINAMICS G150

Line Harmonics Filters compact (LHF compact) are available for the SINAMICS G150 converter cabinet units as

standard option L01 for cabinet integration, including parallel connections with power outputs of ≤ 1500 kW à

SINAMICS G150 Clean Power with integrated Line Harmonic Filter compact.

Integrating the LHF compact increases the cabinet width of the SINAMICS G150 converter cabinet unit by 400 mm or

600 mm depending on power rating (1200 mm for parallel connections).

Examples of SINAMICS G150 and SINAMICS G150 parallel connections with integrated Line Harmonics Filter LHF compact

SINAMICS G150 converter cabinet units with integrated LHF compact can be supplied with all available degrees of

protection from IP20 to IP54.

Converters with a Line Harmonics Filter compact can be optionally equipped with a main switch including fuses. A

main contactor or a circuit breaker are always essential (mandatory option L13 / main contactor or L26 / circuit

breaker). These components are installed in each case in the SINAMICS G150 Clean Power cabinet unit between

the mains supply connection and the LHF compact, so that the filter and converter are always protected and switched

as a common unit.

SINAMICS G150 Clean Power with integrated Line Harmonics Filter compact (LHF compact)

The relative short-circuit power RSC (Relative Short Circuit power) of the supply system must be at least RSC = 10. If

the short-circuit power is any smaller, the line-side resonant frequency will become detuned and the fundamental

wave of the line voltage may increase significantly until it reaches values beyond the permissible line voltage

tolerance of the converter.

It does not make technical sense to use Line Harmonics Filters compact with a 12-pulse power supply connection, as

this does not achieve any additional reduction in the harmonic effects on the supply.

Line Harmonics Filters compact can also be operated at ambient temperatures of > 40°C up to a maximum of 50 °C,

with the same derating factors applicable as to SINAMICS G150 converters.

Line Harmonics Filters compact can be used in both grounded systems (TN/TT) and non-grounded systems (IT).

Line Harmonics Filters compact should not be operated on supply systems with reactive current compensation

systems, nor in combination with other 6-pulse converters that are not equipped with Line Harmonics Filters, nor in

combination with devices that operate with pronounced phase angle control.

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Line Harmonics Filters compact are suitable for both, 50 Hz and 60 Hz supply systems. If converters with a Line

Harmonics Filter compact are operated on 60 Hz supplies with voltages at the top end of the relevant permissible line

connection voltage range, the permissible upper line voltage tolerance is limited to +8 %, because the voltage at the

rectifier input is increased slightly relative to the line voltage as a result of the filter design.

Line supply voltage range Line supply voltage Permissible upper line voltage tolerance

380 V – 480 V 3AC / 60 Hz up to 460 V / 60 Hz + 10 %

480 V / 60 Hz + 8 %

500 V – 600 V 3AC / 60 Hz up to 600 V / 60 Hz + 10 %

660 V – 690 V 3AC / 60 Hz up to 660 V / 60 Hz + 10 %

690 V / 60 Hz + 8 %

Permissible line voltage tolerances when converters with Line Harmonics Filters compact are operated on 60 Hz supplies

If a Braking Module is installed in a converter with a Line Harmonics Filter compact, the Braking Module must always

be set to the upper response threshold (corresponding to the factory setting). This setting must not be changed.

After the converter has been disconnected from the supply system, the filter capacitors must be almost fully

discharged before the converter may be connected to the supply again. This is why the converter is locked out from

reconnection to the supply for a period of 30 s. This lockout function is provided by a time relay on all SINAMICS

G150 converters with LHF compact (option L01).

For this reason, it is a standard feature of G150 converters with installed option L01 that they cannot be quickly

restarted after a power outage or a fault trip nor can the kinetic buffering function be used to bridge brief line dips or

failures which last for a period of < 30 s.

The restart delay time can however be reduced by use of the supplementary option L76 (quick discharge of filter

capacitors). Option L76 shortens the standard restart delay time from 30 s down to around 3 - 5 s.

Information about commissioning:

On converters with LHF compact, the dynamic response of the speed controller should not be set too high, i.e. the

speed controller gain setting Kp should be in the lower range and the speed controller integral time T in the higher

range. Where appropriate, the filter time constant of the Vdc compensation (p1806) should be raised to values within

the range from approximately 20 ms to approximately 100 ms.

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1.5.3 Line filters (radio frequency interference (RFI) suppression filter or EMC filter)

1.5.3.1 General information and standards

Line filters limit the high-frequency, conducted interference emitted by variable-speed drive systems in the frequency

range from 150 kHz to 30 MHz and therefore contribute to improving the Electromagnetic Compatibility (EMC) of the

overall system.

The electromagnetic compatibility describes - according to the definition of the EMC directive - the "capability of a

device to work satisfactorily in the electromagnetic environment without itself causing electromagnetic interference

which is unacceptable for other devices present in this environment".

To guarantee that the appropriate EMC directives are observed, the devices must demonstrate a sufficiently high

noise immunity, and also the emitted interference must be limited to acceptable values.

The EMC requirements for "Adjustable speed electrical power drive systems" are defined in the EMC product

standard EN 61800-3. A variable-speed drive system (or Power Drive System PDS) in the context of this standard

comprises the drive converter and the electric motor including cables. The driven machine is not part of the drive

system.

EMC product standard EN 61800--3 defines different limits depending on the location of the drive system and refers

to installation sites as "first" and "second" environments.

Definition of "first" and "second" environment

· "First" environment:

Residential buildings or locations at which the drive system is directly connected to a public low-voltage

supply without intermediate transformer.

· "Second" environment:

Locations outside residential areas or industrial sites which are supplied from the medium-voltage network

via a separate transformer.

Second

environment

Low-voltage

public network

Medium-voltage network

Drive (noise

source)

Equipment

(affected by

interference)

Conducted

interference

Measuring point for

conducted

interference

10 m

Measuring point for

radiated interference

Limit of facility

First

environment

Low-voltage

industrial network

"First" and "second" environment as defined by EMC product standard EN 61800-3

Four different categories are defined in EN 61800-3 depending on the location and the output of the variable-speed

drive.

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Definition of categories C1 to C4 and associated permissible interference voltage limits

· Category C1:

Drive systems with rated voltages of < 1000 V for unlimited use in the "first" environment

· Category C2:

Fixed-location drive systems with rated voltages of <1000 V for use in the "second" environment. Use in the

"first" environment is possible if the drive system is installed and used by qualified personnel. The warning

and installation information supplied by the manufacturer must be observed.

· Category C3:

Drive systems with rated voltages of < 1000 V for unlimited use in the "second" environment.

· Category C4:

Drive systems with rated voltages of ³ 1000 V or for rated currents of ³400 A for use in complex systems in

the "second" environment.

The diagram below shows the permissible interference voltage limits for categories C1, C2 and C3. Category C3 is

subdivided again into currents of < 100 A and > 100 A. The higher the category, the higher the permitted limit values

for conducted interference emissions (interference voltages). The requirements of category C1 can be met only

through heavy filtering (blue limit curve below), while category C4 demands only minimal filtering and is therefore not

included in the diagram.

Permissible interference voltage limits in dB[mV] for categories C1, C2 and C3 (QP = quasi-peak values)

SINAMICS equipment is used almost exclusively in the "second" environment as defined by categories C3 and C4. It

is therefore equipped as standard with line filters for the "second" environment, category C3. This applies to

SINAMICS G130 Chassis units, SINAMICS G150 converter cabinet units, the Infeeds of the SINAMICS S120

modular system (Basic Line Modules, Smart Line Modules and Active Line Modules) in Chassis and Cabinet Modules

formats and to the SINAMICS S150 converter cabinet units. Line filters compliant with category C3 are suitable for

TN or TT systems with grounded neutral.

Additional line filters are available as options for applications in the "first” environment in accordance with category

C2. This applies to SINAMICS G130 and G150 converters, all Infeeds of the SINAMICS S120 modular system (Basic

Line Modules, Smart Line Modules and Active Line Modules) in Chassis and Cabinet Modules formats and to the

SINAMICS S150 cabinet units. The optional line filters can be ordered as option L00 for all SINAMICS cabinet units

and are installed in each case in the Line Connection Modules LCM. Line filters compliant with category C2 are

suitable for TN or TT systems with grounded neutral.

Since the interference or leakage currents flowing across the line filters increase in proportion to the motor cable

length as described in section "Operating principle of line filters", the interference suppression effect of the line filters

decreases as the cable length increases. For this reason, the line filters supplied as standard reliably comply with the

interference voltage limits of category C3 and the additional line filters available as options with the relatively low

interference voltage limits of category C2 only if the motor cables used do not exceed the lengths specified in the

table below.

Frequency [MHz]

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SINAMICS converter or Infeed Maximum permissible motor cable length (shielded)

(e.g. PROTOFLEX EMV-FC or Protodur NYCWY)

G130 100 m

G150 100 m

S120 Basic Line Module 100 m

S120 Smart Line Module 300 m

S120 Active Line Module

+ Active Interface Module

300 m

S150 300 m

Max. permissible motor cable length to ensure compliance with interference voltage limits of category C3 by

standard line filters or with interference voltage limits of category C2 by the additional, optional line filters

Notes about the table:

· In the case of single-motor drive systems in which one motor is supplied by a G130, G150 or S150 converter

or by an S120 Line Module with an S120 Motor Module, the stated motor cable lengths refer to the distance

between the converter or Motor Module and the motor as measured along the cable and already allow for

the fact that several cables must be routed in parallel for high-output drives.

· In the case of multi-motor drives in which one S120 Line Module supplies a DC busbar to which multiple

Motor Modules are connected, the stated motor cable lengths refer to the total cable length, i.e. the sum of

the distances between individual Motor Modules and the relevant motors. The stated lengths also allow for

the fact that several cables must be routed in parallel for high-output drives.

· When S120 Line Modules (Basic Line Modules, Smart Line Modules, Active Line Modules) are connected in

parallel, the stated motor cable lengths apply in each case to one of the parallel-connected Line Modules.

· The use of optional line filters (option L00) for parallel connections of S120 Line Modules in Cabinet Modules

format for applications in the "first" environment in accordance with category C2 is possible only if a

separate Line Connection Module LCM is provided for each of the parallel-connected Line Modules. Option

L00 is not suitable for implementing an arrangement in which one Line Connection Module LCM is shared

by two Line Modules in a "mirror-image" mechanical setup.

Standards

EN 61800-3

Adjustable speed electrical power drive systems, part 3: EMC requirements and specific test methodes

Variable-speed electrical drives fall into the scope of EMC product standard EN 61800-3 with regard to interference

emissions. This standard has been discussed in detail above.

EN 55011

Industrial, scientific and medical (ISM) radio-frequency equipment - Radio disturbance characteristics -

Limits and methods of measurement

Before the EMC product standard was introduced, variable-speed electrical drives were covered by the scope of

standard EN 55011 which defines limit values for the interference emissions of industrial, scientific and medical radio-

frequency equipment. EN 55011 defines two classes of limit value:

· Class A:

Equipment in class A is suitable for use in all locations except residential areas and other areas connected

directly to a low-voltage distribution system which (also) supplies residential buildings. Equipment in class A

must remain within the limits defined for class A.

à Class A therefore corresponds to the "second" environment defined by EN 61800-3.

· Class B:

Equipment in class B is suitable for use in residential areas and other areas connected directly to a low-

voltage distribution system which (also) supplies residential buildings. Equipment in class B must remain

within the limits defined for class B.

à Class B therefore corresponds to the "first" environment defined by EN 61800-3.

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These classifications are therefore used to define the limit values for conducted interference emissions,

corresponding exactly to categories C1 to C3 as defined in EN 61800-3.

· Class B1:

à This class corresponds to category C1 of EN 61800-3

· Class A1:

à This class corresponds to category C2 of EN 61800-3

Class A2:

à This class corresponds to category C3 of EN 61800-3

1.5.3.2 Line filters for the "first" environment (residential) and "second" environment (industrial)

Line filters or RFI suppression filters limit the high-frequency harmonic effects on the supply systems of the drive by

reducing the conducted emissions in the frequency range between 150 kHz and 30 MHz. They ensure that the

disturbances produced by the variable-speed drive are mainly kept inside the drive system itself and that only a small

percentage (within the permissible tolerance range) can spread into the supply system.

The diagram below shows a variable-speed drive system which is connected to a TN system with grounded starpoint.

The drive system consists of a cabinet-mounted SINAMICS G130 Chassis unit which is feeding a motor over a

shielded motor cable. The purpose of this example is to explain the operating principle of the standard and optional

line filters.

Variable-speed drive system PDS comprising a cabinet with a SINAMICS G130 Chassis and a motor

1.5.3.3 Operating principle of line filters

High-frequency interference in the variable-speed drive system is caused by the IGBTs (Insulated Gate Bipolar

Transistors) switching at high speed in the motor-side inverter of the converter unit. These switching operation

produces very high voltage rate-of-rise dv/dt. For further information about this phenomenon, please refer to the

section "Effects of using fast-switching power components (IGBTs)".

The high voltage rate-of-rise at the inverter output generates large, high-frequency leakage currents which flow to

ground across the capacitance of the motor cable and motor winding. These must return via a suitable path to their

source, i.e. the inverter. When shielded motor cables are used, the high-frequency leakage or interference currents

ILeak pass via the shield to the PE busbar or the EMC shield busbar in the cabinet.

If the cabinet or the Chassis unit would not contain filters of any type which could offer this high-frequency

interference current a low-resistance return path to the inverter, then all the interference current would flow via the

line-side PE connection of the cabinet to the transformer neutral (IPE = ILeak) and from there back to the converter

(rectifier) via the three phases of the three-phase supply. If this were the case, the interference current would

superimpose high-frequency interference voltages on the line voltage and thus influence or even destroy other loads

connected to the same point of common coupling as the cabinet itself. The interference at the connection point would

match the level defined by category C4.

IPE

ILeak

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Due to the line filter which is a standard feature of SINAMICS Chassis the high-frequency interference current gets a

low-resistance return path to its source so that a high percentage of the interference current ILeak can flow via the filter

inside the Chassis unit. As a result, the supply system is loaded with lower interference currents IPE < ILeak and the

interference level at the point of common coupling drops to the level of category C3.

If the optional line filter is installed in the cabinet in addition to the standard line filter fitted to SINAMICS Chassis,

almost all the interference current ILeak is diverted before it can exit the drive system and the load on the power

supply is reduced still further (IPE << ILeak), i.e. the interference level drops to the value defined for category C2.

High-frequency interference current at the line-side PE connection as a function of line filters

1.5.3.4 Magnitude of leakage or interference currents

The magnitude of the high-frequency leakage currents depends on a large number of drive parameters. The most

important influencing factors are:

· Level of the line voltage VLine or the DC link voltage VDCLink of the converter,

· Voltage rate-of-rise dv/dt produced by fast-switching IGBTs in the inverter,

· Pulse frequency fP of the inverter,

· Converter output with or without motor reactor or motor filter,

· Impedance ZW or capacitance C of motor cable,

· Inductance of grounding system and all ground and shield connections.

The inductance values of the grounding system and the exact grounding conditions are normally not known so it is very

difficult in practice to precisely calculate the leakage currents that are likely to occur. It is however possible to work out

the theoretical maximum values of the leakage current ILeak carried by the motor cable shield if we assume that the

grounding system inductance is negligible and the line filter action is ideal. In this case, the peak value of leakage

current îLeak can be calculated as follows from the DC link voltage VDCLink and the impedance ZW of the motor cable:

DCLink

Leak Z

î=.

If we apply this formula to the converters and inverters in the SINAMICS range and assume the Infeed to be

400 V 3AC plus the maximum number of parallel motor cables nmax and the maximum cross-sections of shielded

motor cables Amax, then the magnitudes of the theoretical peak values îLeak of the leakage currents carried by the

motor cable shields are calculated to be:

· Booksize format 1.5 kW - 100 kW îLeak = 10 A – 30 A

· Chassis format 100 kW - 250 kW îLeak = 30 A – 100 A

· Chassis format 250 kW - 800 kW îLeak = 100 A – 300 A

The associated rms values ILeak are approximately 10 times lower when the following supplementary conditions

apply:

· Pulse frequency fP matches factory setting

· 300 m shielded motor cable (with nmax and Amax)

IPE without Line filter (category C4) IPE with Line filter (category C3) IPE with Line filter (category C2)

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Both, the peak values and rms values increase in proportion to the line voltage or DC link voltage. Peak values are

not influenced by pulse frequency or cable length while rms values increase in proportion to pulse frequency and

cable length.

Since the above analysis does not take the grounding system inductance into account, the real values are generally

lower. If motor reactors or motor filters are installed, the leakage currents are reduced even further.

What proportion of the high-frequency leakage current ILeak carried by the motor cable shield reaches the line-side PE

connection depends on the line filters in the converter Chassis unit or converter cabinet, as described on the previous

page. The oscillograms shown in the previous page provide a rough guide as to the reduction in leakage currents at

the PE connection that can be achieved depending on the line filters used. Even when line filters in accordance with

category C2 are installed, leakage current peak values of > 1 A might occur at the PE connection with the largest

units in Booksize format and of 10 A with the largest units in Chassis format.

As the analysis above makes clear, high-frequency leakage currents at the line-side PE connection are not negligible,

even when relatively extensive RFI suppression measures are implemented. For this reason, it is not generally

possible to use line-side residual-current circuit breakers (RCCBs) or universal-AC/DC-sensitive residual current

monitors on SINAMICS drives in the power range of the converters described in this engineering manual. This

applies to both, RCCBs with an operating threshold of 30 mA for personnel protection as well as to RCCBs with an

operating threshold of 300 mA for fire protection. Experience indicates that only drives with short motor cable lengths

of < 10 m and and power ratings up to about 0.5 kW can operate satisfactorily on 30 mA RCCBs. The same applies

to drives with short motor cable lengths of < 10 m and power ratings up to about 5 kW on 300 mA RCCBs. For further

information, please refer to the "Guideline for Residual-Current Circuit Breakers and Electric Drives" (Leitfaden für

Fehlerstrom-Schutzeinrichtungen und elektrische Antriebe) published by the ZVEI (German Electrical and Electronic

Manufacturers' Association).

1.5.3.5 EMC-compliant installation

To ensure that the line filters can achieve the intended filtering effect, it is essential to install the entire drive system

correctly. The installation must be such that interference current can find a continuous, low-inductance path without

interruptions or weak points from the shield of the motor cable to the PE or EMC shield busbar and the line filter back

to the inverter.

Compliance with categories C2 and C3 of EMC product standard EN 61800-3 therefore requires a shielded cable for

the connection between converter and motor. For higher outputs in the SINAMICS Chassis and cabinet unit power

range, a symmetrical 3-wire, three-phase cable should be used to make the connection whenever possible.

Shielded cables with symmetrically arranged three-phase conductors L1, L2 and L3 and an integrated, 3-wire,

symmetrically arranged PE conductor, such as the PROTOFLEX EMV-FC, type 2XSLCY-J 0.6/1 kV illustrated below

which is supplied by Prysmian, are ideal.

Shielded, symmetrically arranged three-phase cable with 3-wire PE conductor

Alternatively, it is also possible to use a shielded cable containing only three-phase conductors L1, L2 and L3 in a

symmetrical arrangement, for example, 3-wire cables of type Protodur NYCWY. In this case, the PE conductor must

be routed separately as close as possible and in parallel to the 3-wire motor cable.

For outputs in the Booksize and Blocksize unit power range, and for lower outputs in the Chassis and cabinet unit

power range, it is also possible to use shielded, asymmetrical, 4-wire cables (L1, L2, L3 plus PE) such as power

cables of type MOTION-CONNECT.

L2 L3

PE PE

L2 L3

PE PE

L1L2

ideal symmetrical 3-wire cable plus

symmetrically arranged PE conductor

symmetrical 3-wire cable with

separately routed PE conductor

asymmetrical 4-wire cable

including the PE conductor

Shielded three-phase cables with concentric shield

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Effective shield bonding is achieved if EMC cable glands are used to create a solid 360° contact between the shield

and motor terminal box and, at the other side in the converter cabinet, a solid 360° contact with the EMC shield

busbar using EMC shield clips. An alternative shield connection to the PE busbar in the converter using only long,

braided "pigtails" is less suitable, particularly if the pigtails are very long, as this type of shield bond represents a

relatively high impedance for high-frequency currents. Further additional shield bonds between the converter and

motor, e.g. in intermediate terminal boxes, must never be created as the shield will then become far less effective in

preventing interference currents from spreading beyond the drive system.

Shield bonding to the motor terminal box

using an EMC gland

Shield bonding to the EMC shield busbar in the converter

using an EMC shield clip

The shielded cable with well bonded shield at both ends ensures that interference currents can flow back easily to the

cabinet.

The housing of the SINAMICS Chassis containing the standard, category C3 line filter must be connected inside the

cabinet to the PE busbar and the EMC shield busbar with a low-inductance contact. The connection can be made

over a large area using metal construction components of the cabinet. In this case, the contact surfaces must be bare

metal and each contact point must have a minimum cross-section of several cm2. Alternatively, this connection can

be made with short ground conductors with a large cross-section (≥ 95 mm2). These must be designed to have a low

impedance over a wide frequency range, e.g. made of finely stranded, braided round copper wires or finely stranded,

braided flat copper strips.

The same rules apply to the connection of the optional category C2 line filter to the PE busbar and the EMC shield

busbar.

The optional line filter must always be combined with a line reactor, otherwise it cannot achieve its full filtering effect.

If the motor cable used were unshielded rather than shielded, the high-frequency leakage currents would be able to

return to the cabinet via an indirect path, i.e. across the motor cable capacitance. They would inevitably flow to the

cable rack and thus to system ground. From here they would continue to the transformer neutral point along

undefined paths and finally via the three phases of the supply system back to the converter. They would bypass the

line filter, rendering it ineffective, with the result that the system would comply with category C4 only.

Compliance with category C4 in complex installations with rated currents ≥ 400 A in an industrial environment and in

IT systems (see section below) in accordance with EN 61800-3 is perfectly acceptable. In this case, the plant

manufacturer and the plant operator must agree upon an EMC plan, i.e. individual plant-specific measures to achive

electromagnetic compatibility. These could include, for example, plant-wide use of highly interference-immune

components (which would include SINAMICS devices and their system components), and strict separation of

interference sources and potentially susceptible equipment, for example, through systematic separate routing of

power and signal cables. Under the specified boundary conditions, use of shielded motor cables is no longer

essential in terms of EMC, but is still recommended for the purpose of reducing bearing currents in the motor in

installations where motor reactors or motor filters are not installed in the converter.

Basically it is also possible to reduce conducted interference emissions to the low values of category C3 according to

EN 61800-3 when unshielded motor cables are used. However, very complicated filtering mechanisms capable of

drastically reducing the voltage rate-of-rise and thus also the interference currents would have to be provided at the

inverter output. In view of the volume and the costs involved in implementing extensive filtering at the inverter output

as well as the negative impact of filters on the dynamic control response and accuracy of the drive, this option does

not in practice generally constitute a viable alternative to the use of shielded motor cables in cases where compliance

with the limits stipulated by catagory C3 or even category C2 is essential.

Motor terminal box

EMC gland

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Line filters and IT systems

The standard line filters for category C3 and the optional line filters for category C2 are suitable for use only in

grounded supply systems (TN and TT systems with grounded neutral). Where SINAMICS equipment is to be

operated on an ungrounded (IT) supply system, the following must be noted:

· In the case of standard line filters, the connection between the filter and ground must be interrupted when

the equipment is installed or commissioned. This can be done simply by removing a metal clip as described

in the operating instructions.

· Optional line filters for category C2 must not be used at all.

If these rules are not followed, the line filters will be overloaded and irreparably damaged in the event of a ground

fault at the motor side. After the ground connection of the standard RFI suppression filter has been removed, the

units generally conform only to category C4 as defined by EMC product standard EN 61800-3 (see previous page for

relevant explanations).

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1.6 SINAMICS Infeeds and their properties

SINAMICS Infeeds generate a DC voltage (DC link voltage VDCLink) from the line voltage of the 3-phase AC supply

system. This DC voltage is smoothed by DC link capacitors. The Infeeds are integral components of the SINAMICS

G130, G150 and S150 converter units and are available as stand-alone components for of the SINAMICS S120

modular drive system. In the latter case, they are available in Chassis or Cabinet Modules format for two-quadrant

operation (Basic Infeed) or four-quadrant operation (Smart Infeed and Active Infeed).

1.6.1 Basic Infeed

The Basic Infeed is a robust, unregulated Infeed for two-quadrant operation (i.e. the energy always flows from the

supply system to the DC link). This Infeed is not designed to regenerate energy from the DC link back to the supply

system. If regenerative energy is produced for brief periods by the drive, e.g. during braking, it must be converted to

heat by a Braking Module connected to the DC link combined with a braking resistor.

The Basic Infeed consists of a line-commutated, 6-pulse, three-phase rectifier equipped with thyristors or diodes. A

line reactor with a relative short-circuit voltage of 2 % is generally connected on the line side. Further details can be

found in the section "Line reactors" and in the chapters on specific unit types.

The Basic Infeed is an integral component of the power sections of SINAMICS G130 chassis units (with thyristors)

and SINAMICS G150 cabinet units (with thyristors up to outputs of ≤ 2150 kW and with diodes for higher outputs).

The Basic Infeed is also available as a separate Infeed in the modular SINAMICS S120 system in Chassis and

Cabinet Modules format (thyristors at lower outputs and diodes at 900 kW / 400 V and 1500 kW / 500 V-690 V).

SINAMICS S120 Basic Infeed comprising a Basic Line Module with thyristors and a line reactor with vk= 2%

The Basic Infeed is a line-commutated rectifier which, from the three-phase line voltage VLine, produces an

unregulated, load-dependent DC link voltage VDCLink. Under no-load conditions, the DC link is charged to the peak

line voltage value, i.e. VDCLink = 1.41 • VLine. When loaded the DC link voltage decreases. When partially loaded the

DC link voltage will be VDCLink ≈ 1.35 • VLine and at full load,

VDCLink ≈ 1.32 • VLine.

As the DC link voltage is unregulated, line voltage fluctuations cause the DC link voltage to fluctuate correspondingly.

The processes for precharging the connected DC link are very different depending on the device variant used:

In the case of SINAMICS G130 and G150 converters in which the Basic Infeed is an integral component of their

power units, a small precharging rectifier equipped with diodes is connected in parallel with the main rectifier

equipped with thyristors (Exceptions: G150 parallel connections in the output power range from 1750 kW to 2700 kW.

For further information about these units, please refer to chapter "Converter Cabinet Units SINAMICS G150"). If this

arrangement is applied to the voltage at the line side, the DC link is charged by means of the precharging rectifier

and the associated precharging resistors. During this time, the main rectifier is disabled (i.e. the thyristors are not

controlled). As soon as the DC link is charged, the thyristors in the main rectifier are controlled in such a way that

they are triggered at the earliest possible moment. As a result, the thyristor rectifier essentially behaves during

operation in the same way as a diode rectifier. The operational current flows almost entirely via the main rectifier

since it encounters much less resistance than via the parallel-connected precharging rectifier and its precharging

resistors.

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Precharging with G130 and G150 converters via a separate precharging rectifier and precharging resistors

The principle of precharging involves the use of ohmic resistors and is, therefore, subject to losses. This means that

the precharging resistors must be thermally dimensioned to support precharging of the DC link for their G130 or

G150 converter without becoming overloaded. Additional DC link capacitances cannot be precharged. For this

reason, other S120 Motor Modules, for example, must not be connected to the DC link of a SINAMICS G130 or G150

converter. Complete precharging of the DC link is only permitted every 3 minutes.

In the case of Basic Line Modules for the SINAMICS S120 modular system equipped with thyristors, the DC link is

charged via the rectifier thyristors by changing the firing angle (phase angle control). During this process, the firing

angle is increased continuously for 1 second until it reaches the full firing angle setting. This precharging principle

results in hardly any losses, which means that an extremely high DC link capacitance could be precharged. The

permissible DC link capacitance for the connected inverters (S120 Motor Modules), however, must be limited to

protect the thyristors against an excessive recharge current entering the DC link capacitance when the voltage is

restored following a line voltage dip. Despite this, the limit for the permissible DC link capacitance is relatively high

due to the robust line-frequency thyristors.

The maximum permissible DC link capacitance for the different S120 Basic Line Modules can be found in the section

“Checking the maximum DC link capacitance” of the chapter “General Information about Built-in and Cabinet Units

SINAMICS S120”.

Precharging with S120 Basic Line Modules equipped with thyristors via phase angle control of the thyristors

In the case of Basic Line Modules for the SINAMICS S120 modular system equipped with diodes, precharging is

carried out via resistors, which create losses. To precharge the DC link, the rectifier is connected to the supply

system on the line side via a precharging contactor and precharging resistors. Once precharging is completed, the

bypass contactor is closed and the precharging contactor is opened again. Due to the power losses that occurs in the

resistors during precharging, the DC link may be completely precharged only every 3 minutes and the permissible DC

link capacitance of the connected inverters (S120 Motor Modules) is limited to lower values than in the case of Basic

Line Modules with thyristors.

The maximum permissible DC link capacitance for the different S120 Basic Line Modules can be found in the section

“Checking the maximum DC link capacitance” of the chapter “General Information about Built-in and Cabinet Units

SINAMICS S120”.

Precharging with S120 Basic Line Modules equipped with diodes via precharging contactor and precharging resistors

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The precharging circuit consists of a precharging contactor and precharging resistors and their fuse protection.

For S120 Basic Line Modules in Chassis format (equipped with diodes), the precharging circuit including its fuse

protection must be provided by the customer. The components recommended for this purpose can be found in

section "Precharging of the DC link and precharging currents" of chapter "General Information about Built-in and

Cabinet Units SINAMICS S120".

For S120 Basic Line Modules in Cabinet Modules format (equipped with diodes), the precharging circuit including its

fuse protection is always located in the Line Connection Module LCM that is connected upstream of the Basic Line

Module (equipped with diodes).

The bypass contactor is a circuit breaker.

For S120 Basic Line Modules in Chassis format (equipped with diodes), the bypass contactor (circuit breaker) must

be provided by the customer.

For S120 Basic Line Modules in Cabinet Modules format (equipped with diodes), the bypass contactor (circuit

breaker) is always located inside the Line Connection Module LCM that is connected upstream of the Basic Line

Module (equipped with diodes).

IMPORTANT:

It is absolutely essential that the precharging contactor and the bypass contactor are controlled by the internal

sequence control of the S120 Basic Line Module (equipped with diodes) (precharging contactor via connector -X9:5,6

and bypass contactor (circuit breaker) via connector -X9:3,4). It is essential that the circuit breaker is opened by an

instantaneous release. For this reason, only circuit breakers equipped with instantaneous undervoltage release may

be used.

To achieve an increased output power rating, it is possible to connect up to four S120 Basic Line Modules in parallel

(including 6-pulse and 12-pulse configurations). Further details can be found in the section "Parallel connections of

converters".

Due to the operating principle of the 6-pulse three-phase bridge circuit, the Basic Infeed causes relatively high

harmonic effects on the supply system. The line current contains a high harmonic content with harmonic numbers

h = n * 6 ± 1, where n assumes integers 1, 2, 3, etc. The Total Harmonic Distortion factor of current THD(I) is

typically in the range from about 30 % to 45 %. For further information about harmonic characteristics, please refer to

the section "Harmonic effects on the supply system". Line Harmonics Filters LHF can be installed on the line side of

G130 Chassis units and G150 cabinet units in order to reduce the effects of harmonics on the supply. These reduce

the total harmonic distortion factor THD(I) to below 7.5 %. A similar reduction can also be achieved with 12-pulse

circuits, i.e. by supplying two Basic Line Modules from a three-winding transformer with a 30 ° phase displacement

between its voltages.

The criteria for defining of the required transformer power rating, taking into account the harmonic load as well as the

characteristics of three-winding transformers in 12-pulse operation, are described in the section “Transfomers”.

1.6.2 Smart Infeed

The Smart Infeed is a stable, unregulated rectifier / regenerative unit for four-quadrant operation, i.e. the energy flows

from the supply system to the DC link and vice versa. The current values stated in the catalogs are available in both,

rectifier and regenerative operation.

The Smart Infeed consists of an IGBT inverter, which operates on the line supply as a line-commutated 6-pulse

bridge rectifier / regenerative unit. In contrast to the Active Infeed, the IGBTs are not active pulsed using the pulse-

width modulation method. In rectifier operation (motor operation) the current flows via the diodes integrated into the

IGBT modules from the line supply to the DC link, so that a line-commutated, 6-pulse diode bridge circuit is present in

motor operation. In regenerative operation the current flows via the IGBTs, which are synchronised at the line

frequency. Thus, a line-commutated, 6-pulse IGBT bridge circuit is present at regenerative operation.

As IGBTs, in contrast to thyristors, can be switched off at any time, inverter shoot-through during regenerative

operation caused by supply system failures cannot occur in contrast to rectifier / regenerative units equipped with

thyristors.

On the line side, the Smart Infeed is normally equipped with a line reactor having a relative short circuit voltage of

vk = 4 %.

The Smart Infeed is available as a stand-alone Infeed of the SINAMICS S120 modular system in Chassis and

Cabinet Modules format.

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SINAMICS S120 Smart Infeed comprising a Smart Line Module and a line reactor with vk= 4%

The IGBTs for regenerative operation of the Smart Infeed are always switched on at the natural firing point and

switched off after 120º (electr.) independently from the direction of the energy flow. As a result of this, a current resp.

energy flow from the supply to the DC link or vice-versa is possible at any time. The direction of the actual current

resp. energy flow is only determined by the voltage ratios between the supply and the DC link. In steady-state motor

operation, the DC link voltage during the possible current-flow phase is always smaller than the supply voltage, so

that the current flows from the supply to the DC link via the diodes. In steady-state regenerative operation, the DC

link voltage during the possible current-flow phase is always larger than the supply voltage, so that the current flows

from the DC link to the supply via the IGBTs. This control principle offers the advantage that the Smart Infeed can

react relatively fast to load variations and can also change the direction of the current resp. energy flow at any time.

However, a characteristic of the control principle described is that a harmonic reactive current flows on the line side in

no-load operation. The cause is the sinusoidal supply voltage on the one hand, and an almost perfectly smoothed DC

voltage in the DC link during no-load operation at the other hand. Consequently, directly after the firing of the IGBTs,

a short-term current flows from the DC link to the supply because, at this time, the supply voltage is slightly lower

than the DC link voltage. If the supply voltage then reaches its peak value, the voltage ratios are reversed and thus

the current direction is also reversed. This reactive current decreases as the load on the Smart Infeed increases and

disappears completely under full load.

The reactive current under no load can be prevented by a regenerative operation disable command (parameter

p3533: Infeed, inhibit generator mode).

It can also be helpful to inhibit regenerative operation of the Infeed to obtain greater stability in operation when the

unit is operating in motor mode if one or more of the following conditions apply:

· Operation of the Smart Infeed on a weak, unstable supply system with frequent line voltage dips.

· Operation of the Smart Infeed within a DC configuration with very high DC link capacitance CDCLink.

· 12-pulse operation of the Smart Infeed on a three-winding transformer.

· Mixed Smart Infeed / Basic Infeed operation.

Regenerative operation can be inhibited and enabled by the higher-level automation system, for example, if the

process steps in which regenerative operation can occur are clearly defined in the process control system.

Since the Smart Infeed is a line-commutated Infeed, it generates an unregulated, load-dependent DC link voltage

VDCLink from the three-phase line voltage VLine.

In motor operation, the DC link voltage decreases by a slightly larger amount than on the Basic Infeed, because the

voltage drop across the 4% reactor is higher than across the 2% reactor on the Basic Infeed. Under partial load in

motor operation, VDCLink ≈ 1.32 • VLine, while the figure for full load in motor operation is

VDCLink ≈ 1.30 • VLine (motor mode).

The DC link voltage is higher in regenerative operation than in motor operation, because the direction of current flow

reverses and thus also the voltage drop across the 4% reactor. Under partial load in regenerative operation, VDCLink ≈

1.38 • VLine, while the figure for full load in regenerative operation is

VDCLink ≈ 1.40 • VLine (regenerative).

Because the DC link voltage is not regulated, fluctuations in the line voltage and changes in the operating state

(motor mode / regenerative mode) cause it to fluctuate accordingly.

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With S120 Smart Line Modules, the connected DC link is precharged via resistors, which create losses. To precharge

the DC link, the Smart Line Module is connected to the supply system on the line side using a precharging contactor

and precharging resistors. Once precharging is complete, the bypass contactor is closed and the precharging

contactor opened again. It is absolutely essential that the precharging and main circuits have the same phase

sequence because, during the brief period of overlap when both contactors are closed at the same time, the

precharging resistors might otherwise be overloaded and irreparably damaged. Due to the power losses that occur in

the resistors during precharging, the DC link may be completely precharged only every 3 minutes and the permissible

DC link capacitance of the connected inverters (S120 Motor Modules) is limited to relatively low values. This

restriction is not only required due to the power losses, however, but also to protect the diodes in the IGBT modules

against an excessive recharge current from entering the DC link capacitors when the voltage is restored following

voltage dips.

The maximum permissible DC link capacitance for the different S120 Smart Line Modules can be found in the section

“Checking the maximum DC link capacitance” of the chapter “General Information about Built-in and Cabinet Units

SINAMICS S120”.

Precharging with S120 Smart Line Modules via precharging contactor and precharging resistors

The precharging circuit comprises a precharging contactor and precharging resistors and is an integral component of

the S120 Smart Line Modules. This means that the only equipment to be provided outside the S120 Smart Line

Module is the fuse protection for the precharging circuit.

For S120 Smart Line Modules in Chassis format, the fuse protection for the precharging circuit must be provided by

the customer. The fuses recommended for this purpose can be found in section "Precharging of the DC link and

precharging currents" of chapter "General Information about Built-in and Cabinet Units SINAMICS S120".

For S120 Smart Line Modules in Cabinet Modules format, the precharging circuit is always protected by fuses located

in the Line Connection Module LCM that is connected upstream of the Smart Line Module.

The bypass contactor, which can be a contactor or a circuit breaker depending on the power rating, is always located

outside the S120 Smart Line Module.

For S120 Smart Line Modules in Chassis format, the bypass contactor must be provided by the customer.

For S120 Smart Line Modules in Cabinet Modules format, the bypass contactor (contactor or circuit breaker

depending on the power rating) is always located inside the Line Connection Module LCM that is connected

upstream of the Smart Line Module.

IMPORTANT:

It is absolutely essential that the precharging contactor and the bypass contactor are controlled by the internal

sequence control of the S120 Smart Line Module (precharging contactor via internal wiring and bypass contactor /

circuit breaker via connector -X9:3,4). When a circuit breaker is used, it is essential that breaker opening is controlled

by an instantaneous release. For this reason, only circuit breakers equipped with instantaneous undervoltage release

may be used.

To achieve an increased output power rating, it is possible to connect up to four S120 Smart Line Modules in parallel

(including 6-pulse and 12-pulse configurations). Further details can be found in the section "Parallel connections of

converters".

Due to the operating principle of the 6-pulse three-phase bridge circuit, the Smart Infeed causes relatively high

harmonic effects on the supply system. The line current contains a high harmonic content with harmonic numbers

h = n * 6 ± 1, where n assumes integers 1, 2, 3, etc. The harmonic currents produced in rectifier operation (motor

operation) are identical as those of the Basic Infeed and have the same spectral distribution. The Total Harmonic

Distortion factor of the current THD(I) is typically in the range from about 30 % to 45 %. In regenerative operation, the

5th harmonic decreases significantly but all the others increase slightly so that the Total Harmonic Distortion factor

THD(I) only decreases by a few percent. The use of Line Harmonics Filters for the reduction of harmonic effects is

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not permissible with Smart Infeeds due to the different spectrums of the current harmonics in rectifier operation

(motor operation) and in regenerative operation. A reduction of the Total Harmonic Distortion factor (THD)(I) to a

value of approx. 10 % can only be achieved with 12-pulse circuits, i.e. by supplying two Smart Line Modules from a

three-winding transformer with a 30° phase displacement between its secondary voltages.

The criteria for defining of the required transformer power rating, taking into account the harmonic load as well as the

characteristics of three-winding transformers in 12-pulse operation, are described in the section “Transfomers”.

1.6.3 Active Infeed

The Active Infeed is an actively pulsed, stable, regulated rectifier / regenerative unit for four-quadrant operation, i.e.

the energy flows from the supply system to the DC link and vice versa. The current values stated in the catalogs are

available in both rectifier and regenerative operation

The Active Infeed comprises a self-commutated IGBT inverter (Active Line Module ALM), which operates on the

supply system via the Clean Power Filter (Active Interface Module). The Active Line Module operates according to

the method of pulse-width modulation and generates a constant, regulated DC link voltage VDCLink from the three-

phase line voltage VLine. The Clean Power Filter, which is installed between the Active Line Module and the supply

system, filters out, as far as possible, the harmonics from the Active Line Module’s pulse-width modulated voltage

VALM, thereby ensuring a virtually sinusoidal input current on the line side and, therefore, minimal harmonic effects on

the supply system.

The Active Infeed is the highest grade SINAMICS Infeed variant. It is an integral component of SINAMICS S150

cabinet units and is available as a stand-alone Infeed of the SINAMICS S120 modular drive system in Chassis or

Cabinet Modules format.

Active Interface Module AIM Active Line Module ALM

Clean Power Filter

Supply DC Link

VLine

ILine

VALM

IALM

VDC Link

Active Infeed

SINAMICS S120 Active Infeed comprising an Active Interface Module and an Active Line Module

The Active Infeed is a self-commutated rectifier / regenerative unit and produces from the three-phase line voltage

VLine a regulated DC link voltage VDCLink, which remains constant independently from line voltage variations and

supply voltage dips. It operates as a step-up converter, i.e. the DC link voltage is always higher than the peak value

of the line voltage (VDCLink > 1.41 • VLine). The value can be parameterized (1.42 to 2.0) and its factory setting is

VDCLink = 1.50 • VLine

This setting should not be changed without a valid reason. Reducing the factory-set value tends to impair the control

quality while increasing it unnecessarily increases the voltage on the inverter and the motor winding. If the

permissible voltage of the motor winding is sufficiently high (see section "Increased voltage stress on the motor

winding as a result of long cables"), the DC link voltage can be increased from the factory setting to the values

VDCmax specified in the table. This method allows a voltage higher than the line voltage to be obtained at the output of

the inverter or Motor Module connected to the Active Infeed. The table shows the maximum achievable inverter

output voltage as a function of the DC link voltage and the modulation system used in vector control mode (space

vector modulation SVM without overmodulation or pulse-edge modulation PEM).

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Supply voltage

Line

Maximum permissible DC

link voltage in steady-state

operation

VDC max.

Maximum attainable

output voltage with

space vector

modulation

out

max SVM

Maximum attainable

output voltage with

pulse-edge modulation

Vout max. PEM

Units with 380 V – 480 V 3AC 720 V 504 V 533 V

Units with 500 V – 690 V 3AC

in operation with supply voltages

500 V – 600 V 3AC

660 V – 690 V 3AC

1000 V with VLine = 500 V

1080 V with VLine = 600 V

1080 V

700 V with VLine = 500 V

756 V with VLine = 600 V

756 V

740 V with VLine = 500 V

800 V with VLine = 600 V

800 V

SINAMICS Active Infeed: Maximum, continuously permissible DC link voltages and attainable output voltages

As the magnitude of the DC link voltage can be parameterized and the DC link current depends on this parameter

setting, the DC current is not suitable as a criterion for dimensioning the Active Infeed required. For this reason, the

power balance of the drive should always be used as a basis for dimensioning the Active Infeed.

The first important quantity to know is the mechanical power Pmech to be produced on the motor shaft. Starting with

this shaft power value, it is possible to work out the electrical active power PLine to be drawn from the supply system

by adding the power losses of the motor PL Mot, the power losses of the Motor Module PL MoMo and the power losses

of the Active Infeed PL AI to the mechanical power value Pmech.

PLine = Pmech + PL Mot + PL MoMo + PL AI.

It is also possible to use the efficiency factors of the motor (ηMot), Motor Module (ηMoMo) and Active Infeed (η

AI)

instead of the power losses values

PLine = Pmech / (ηMot • ηMoMo • ηAI) .

The active power to be drawn from the supply system depends on the line voltage VLine, the line current ILine and the

line-side power factor cosφLine as defined by the relation

PLine = √3 • VLine • ILine • cosφLine.

This is used to calculate the required line current ILine of the Active Infeed as follows:

ILine = PLine / (√3 • VLine • cosφLine) .

If the Active Infeed is operated according to the factory setting, i.e. with a line-side power factor of cosφLine = 1, so it

draws only pure active power from the supply. Then the formula can be simplified to

ILine = PLine / (√3 • VLine) .

The Active Infeed must now be selected such that the permissible line current of the Active Infeed is higher or equal

to the required value ILine.

At operation with a line-side power factor cosφLine = 1, the resultant line current is generally lower than the motor

current. This is due to the fact that the motor has a typical power factor cosφMot ≤ 0.9 and therefore requires a

relatively high reactive current. However, this is drawn from the DC link capacitors rather than from the supply

system, resulting in a line current that is lower than the motor current.

Due to the fact that the Active Infeed operates as a step-up converter, it maintains the DC link voltage at a constant

level, even at significant line voltage variations and line voltage dips. If the drive must tolerate supply voltage dips of

more that 15 % without tripping, the following points must be noted:

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· The internal auxiliary supply must be fed by a secure, external supply with 230 V (e.g. by means of an

uninterruptible power supply UPS).

· The line-side undervoltage trip level must be parameterized to a correspondingly low value.

· The Active Infeed must be capable of providing current reserves so that it can increase the current to

compensate for the decreasing power in rectifier / regenerative mode resulting from the low voltage level

during the line voltage dip.

More detailed information can be found in the section “Supply systems and supply system types” in the subsection

“Behaviour of SINAMICS converters during supply voltage variations and dips”.

With S150 converters and S120 Active Infeeds, the connected DC link is precharged by means of resistors in the

Active Interface Modules, which creates losses. To precharge the DC link, the Active Interface Module and the

associated Active Line Module are connected to the supply system on the line side via a precharging contactor and

precharging resistors. Once the DC link is precharged, the bypass contactor is closed and the precharging contactor

opened again after 500 ms.

The brief period of overlap during which both contactors are closed is absolutely essential with the Active Infeed. This

is because the precharging contactor not only precharges the DC link capacitors, but also the filter capacitors of the

Clean Power Filter in the Active Interface Module. The overlap therefore ensures that there are no current surges

during charging of the filter capacitors. To ensure a sufficiently long period of overlap, the closing time of the bypass

contactor must not exceed 500 ms.

Furthermore, as a result of the period of overlap, it is absolutely essential that the precharging and main circuits have

the same phase sequence to prevent the risk of overloading and possible irreparable damage to the precharging

resistors.

Precharging with S150 converters and S120 Active Infeeds via precharging contactor and precharging resistors

Due to the power losses which occur during precharging in the resistors, complete precharging of the DC link is only

permitted every 3 minutes and the permissible DC link capacitance of the connected inverter(s) is limited to a

relatively low value.

The maximum permissible DC link capacitance for the different S120 Active Interface Modules / Active Line Modules

can be found in the section “Checking the maximum DC link capacitance” of the chapter “General Information about

Built-in and Cabinet Units SINAMICS S120”.

In the case of S120 Active Line Modules in Chassis format with Active Interface Modules in frame sizes FI and GI,

the precharging circuit (precharging contactor and precharging resistors) and the bypass contactor are integral

components of the Active Interface Module. The precharging circuit in the Active Interface Module is designed short-

circuit proof. The customer is not required to provide fuse protection for the precharging circuit in this case.

In the case of S120 Active Line Modules in Chassis format with Active Interface Modules in frame sizes HI and JI, the

bypass contactor is not an integral component of the Active Interface Module. The bypass contactor, which can be a

contactor or circuit breaker (depending on the output) must have a closing time of 500 ms or less and must be

provided in the customer's plant. The fuse protection for the precharging arm must also be provided by the customer.

The fuses recommended for this purpose can be found in section "Precharging of the DC link and precharging

currents" of chapter "General Information about Built-in and Cabinet Units SINAMICS S120".

In the case of S120 Active Line Modules with Active Interface Modules in Cabinet Modules format, it is either not

necessary to provide fuse protection for the precharging circuit (short-circuit proof design in the Active Interface

Modules in frame sizes FI and GI), or the precharging circuit is protected by fuses inside the Line Connection Module

that is connected upstream of the Active Line Module with Active Interface Module.

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IMPORTANT:

It is absolutely essential that the precharging contactor and the bypass contactor are controlled by the internal

sequence control of the S120 Active Line Module (precharging contactor via connector -X9:5,6 and bypass contactor

via connector -X9:3,4). When a circuit breaker is used as bypass contactor, it is essential that breaker opening is

controlled by an instantaneous release. For this reason, only circuit breakers equipped with instantaneous

undervoltage release may be used.

To achieve an increased output power rating, it is possible to make a parallel connection of up to four S120 Active

Line Modules with the matching Active Interface Modules. Further details can be found in the section "Parallel

connections of converters".

Due to the principle of active pulsing combined with the line-side Clean Power Filter, the harmonic effects on the

supply caused by the Active Infeed are virtually non-existent. The harmonic content of the line current is only very

minor, meaning that there are scarcely any harmonics in the line voltage either. The vast majority of current and

voltage harmonics is typically significantly lower than 1 % of rated current or rated voltage with the Active Infeed. The

total harmonic distortion factors of the current THD(I) and the voltage THD(V) are typically within a range of

approximately 3 %. When self-commutated IGBT Infeeds (S150, S120 Active Line Modules) are used, the system

complies with the limit values stipulated in standard IEEE 519 (Recommended Practices and Requirements for

Harmonic Control in Electrical Power Systems).

The criteria for defining of the required transformer power rating, taking into account the harmonic load are described

in the section “Transfomers”.

Operation of the Active Infeed with a line-side power factor of cosφ < 1

When the Active Infeed, for which the line-side reactive current can be freely parameterized in the firmware, is

operated with a power factor of cosφ < 1, the power losses in the Active Line Module increase. For this reason, the

line current must be reduced in accordance with the derating characteristic shown below.

Permissible line current of the SINAMICS Active Infeed as a function of the line-side power fundamental factor cosφ

Creating an island power system by using the Active Infeed

The standard version of the SINAMICS Active Infeed has been developed as an Infeed component for SINAMICS

drive systems and a three-phase supply system is therefore an essential prerequisite for its use. Using the Voltage

Sensing Module VSM integrated in the Active Interface Module AIM, the Active Infeed senses the magnitude and

phase angle of the line voltage, synchronizes itself with the connected line voltage and frequency and, supported by

a secondary current controller, regulates the DC link voltage for the connected drive configuration to a constant value

which is parameterizable.

Special versions of the Active Infeed are available for applications in which an island power system is to be

generated by means of a self-commutated, line-side converter. Examples of such applications are:

· Shaft generators on ships with Active Infeed for generating an on-board power supply system

· Solar power installations with Active Infeed for generating local island power supply systems.

The versions of the Active Infeed required for this purpose have modified power unit hardware (CIM module with

additional processor) as compared to the standard version, and require supplementary firmware modules (which are

subject to license) in addition to the standard firmware. The power rating range of these special versions is limited.

Further information is available on request.

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Note about the pulse frequency of the Active Infeed

By contrast with SINAMICS S120 Motor Modules for which the pulse frequency can be adjusted within relatively wide

limits, the pulse frequency for SINAMICS S120 Active Line Modules is largely predefined as it needs to be set in a

fixed ratio to the resonant frequency of the Clean Power Filter in the associated Active Interface Module.

For SINAMICS S120 Active Line Modules in Chassis and Cabinet Modules formats, the current controller clock

cycle and the pulse frequency are set at the factory to the values given in the table:

Line supply

voltage

DC link voltage S120 ALM output Rectifier/regenerative

current

ALM current

controller

clock cycle

ALM pulse

frequency

380 V – 480 V 3AC 570 V – 720 V DC 132 kW – 300 kW 210 A – 490 A 250 μs4.00 kHz

380 kW – 900 kW 605 A – 1405 A 400 μs2.50 kHz

500 V – 690 V 3AC 750 V – 1035 V DC 630 kW – 1700 kW 575 A – 1560 A 400 μs2.50 kHz

Factory setting of current controller clock cycle and pulse frequency for S120 Active Line Modules (Chassis and Cabinet

Modules)

For SINAMICS S150 cabinet units with line-side Active Line Module, the current controller clock cycle and the

pulse frequency of the Active Line Module are set at the factory to the values given in the table:

Line supply

voltage

S150 output Rectifier/regenerative

current

Rated output current ALM current

controller

clock cycle

ALM pulse

frequency

380 V – 480 V 3AC 110 kW – 250 kW 197 A – 447 A 210 A – 490 A 250 μs4.00 kHz

315 kW

– 800 kW 549 A – 1262 A 605 A – 1405 A 400 μs2.50 kHz

500 V – 690 V 3AC 75 kW – 315 kW 86 A – 304 A 85 A – 330 A 250 μs4.00 kHz

400 kW – 1200 kW 375 A – 1142 A 410 A – 1270 A 400 μs2.50 kHz

1) With option L04 the ALM of the S150 cabinet unit 315 kW (380 V – 480 V) operates with a current controller clock cycle of 250 μs and a pulse frequency of 4.00 kHz

Factory setting of ALM current controller clock cycle and ALM pulse frequency for SINAMICS S150 cabinet units

Parameter p0092 (Clock synchronous operation pre-assignment/check) is the only means by which the factory

setting can be slightly changed. This parameter allows the current controller clock cycle to be changed from 400 μs to

375 μs to enable isochronous PROFIdrive operation. Changing this setting slightly increases the pulse frequency for

these devices from 2.50 kHz to 2.67 kHz.

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1.6.4 Comparison of the properties of the different SINAMICS Infeeds

The table below shows an overview of all the key properties of the different SINAMICS Infeeds.

SINAMICS Infeed Basic Infeed Smart Infeed Active Infeed

Mode of operation Rectifier mode

(2Q)

Rectifier / regenerative mode

(4Q)

Rectifier / regenerative mode

(4Q)

Stable operation in

regenerative mode

also during line

supply failures

Not relevant Yes Yes

Power semiconductors Thyristors / Diodes IGBT modules IGBT modules

Line-side reactor 2 % 4 % Clean Power Filter in AIM

Power factor cosφ1

(fundamental wave)

at rated output

> 0.96 > 0.96 Parameterizable

(factory setting = 1)

Total Harmonic Distortion

factor of the line current

THD(I) at rated output Typically 3 %

- 6-pulse

- 6-pulse + LHF 1

- 6-pulse + LHF compact 2

- 12-pulse

Typically 30 % - 45 %

Typically 5 % - 7.5 %

Typically 8 % - 10 %

Typically 30 % - 45 %

Typically 8 % - 10 %

EMC filter

category C3 Yes Yes Yes

DC link voltage

at rated output

1.32 • VLine

(non-stabilized)

1.30 • VLine

(non-stabilized)

> 1.42 • VLine

(stabilized and parameterizable)

Voltage at motor winding Low Low Higher than with Basic Infeed

and Smart Infeed

Precharging

- By means of the firing

angle with thyristors

- By means of resistors

with diodes

By means of resistors By means of resistors

Prechargeable

DC link capacitance

- High with thyristors

- Low with diodes Low Low

Typical Efficiency

at rated output > 99.0 % > 98.5 % > 97.5 %

Volume Low Medium High

Price Low Medium High

Comparison of the properties of different SINAMICS Infeeds

1 available only for SINAMICS G130 and SINAMICS G150, see section "Line Harmonics Filter (LHF and LHF compact)"

2 available only for SINAMICS G150 as option L01, see section "Line Harmonics Filter (LHF and LHF compact)"

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The table below shows a direct comparison between the typical time characteristics of line currents in relation to line

voltage (phase voltage V1 = VLine/√3) for G130 / G150 converters and for the different S120 Infeeds at operation with

the rated output.

Comparison of typical line currents with SINAMICS G130 / G150 converters and SINAMICS S120 Infeeds

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1.6.5 – – –

1.6.6 Redundant line supply concepts

General

Certain applications require redundant Infeeds for multi-motor drives or common DC link configurations to increase

availability. This demand can basically be fulfilled by using several independent Infeed units working in parallel on the

common DC link. If one Infeed unit fails the common DC link can be supplied by the remaining Infeed unit, usually

without interruption. Depending on the power rating of the Infeed units the common DC link can continue to operate

at between half and full power. This is dependent on fulfillment of the following requirements:

· Each Infeed must have its own Control Unit.

· The Control Unit of each Infeed must control only the assigned Infeed but not any additional Motor Modules.

· Due to the need for redundancy, the Motor Modules operating on the common DC link must be operated on

a separate Control Unit or multiple separate Control Units in complete independence of the Infeed Modules.

The difference between redundant Infeeds and the parallel connection of Infeeds for increasing the power rating, as

described in the section “Parallel connections of converters”, is the arrangement of the Control Units. At redundant

Infeeds each Infeed is controlled by its own Control Unit. Therefore, each Infeed is completely autonomous. At the

parallel connection of Infeeds, a single Control Unit controls and synchronizes all power units in the parallel

configuration, which behaves as a single Infeed with a higher power rating.

Note:

When several independent Infeeds are used, this can considerably increase the availability of the DC busbar. In

practice, however, 100 % fault tolerance is impossible since certain fault scenarios can still cause an interruption in

operation (such as a short circuit on the DC busbar). Even if these fault scenarios are extremely unlikely to occur, the

risk of their occurring cannot be completely eliminated in practice.

Depending whether the demand for redundancy is related only to the Infeed units or also to the supplying

transformers or the supply systems, different circuit concepts are possible, which are shown and explained below.

Infeed 2

Infeed 1

Control

Unit 1

Control

Unit 2

Supply

Variant 1:

Supply from a single supply system

with a double-winding transformer

Variant 2:

Supply from a single supply system

with a three-winding transformer

Variant 3:

Supply from two independent supply

systems with two transformers

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With variant 1, both redundant Infeeds with the same power rating are supplied from one supply system via a two-

winding transformer. As both Infeeds are supplied with exactly the same voltage on the line side, in normal operation

the current distribution is largely symmetrical, even with unregulated Infeeds. The Infeeds can, therefore, be

dimensioned so that each Infeed can provide half of the total current taking into account a small current derating

factor. If one Infeed fails, only half of the power required will be available. If the full power is required when one Infeed

fails, each Infeed must be dimensioned to provide the full power.

With variant 2, both redundant Infeeds with the same power rating are also supplied from one supply system, but via

a three-winding transformer. The transformer must be designed for redundant operation and be capable of

withstanding up to 100% asymmetrical loading. Depending on the characteristics of the transformer, the line-side

voltages of both Infeeds can have small tolerances of approx. 0.5 % to 1 %. This leads in normal operation with

unregulated Infeeds to a current distribution which is slightly less symmetrical than with variant 1. This must be taken

into account and covered by corresponding current derating factors. If the full power is required when one Infeed

fails, each Infeed must be dimensioned to provide the full power.

With variant 3, both redundant Infeeds with the same power rating are supplied by two independent supply systems

with two separate two-winding transformers. As the voltages of both independent supply systems can be noticeably

different, very large imbalances in the current distribution can occur in normal operation with unregulated Infeeds. If

voltage tolerances between the two supply systems of between 5 % and 10 % have to be dealed with, it is absolutely

necessary, when using unregulated Infeeds, to dimension each Infeed to provide the full power to connected DC

configuration.

Note:

The infeeds labeled "Infeed 1" and "Infeed 2" in the sketch can comprise in each case a single power unit (Power

Module), or a parallel connection of two identical power units (Power Modules). It is basically also possible to

configure parallel connections comprising more than two power units (Power Modules) per "Infeed". In this case,

detailed clarification of the relevant boundary conditions must be requested.

The following paragraphs will explain which of the three redundant line supply concepts (variants 1 to 3) can be

realized with the three Infeed types available with SINAMICS (Basic Infeed, Smart Infeed, Active Infeed) and which

boundary conditions must be observed.

Redundant line supply concepts with the SINAMICS Basic Infeed

With the line-commutated, unregulated SINAMICS Basic Infeed all three variants can be used.

Variant 1 with SINAMICS Basic Infeed, boundary conditions to be observed:

· For each Basic Line Module a line reactor with a short-circuit voltage of 2 % is required.

· If it can be accepted that the common DC link is operating with half the power when a Basic Line Module

fails, each Basic Line Module can be selected for half the input current taking into account a current derating

of 7.5 % related to the rated current, as with the 6-pulse, parallel connection of Basic Line Modules. If the full

power is still required by the common DC link when a Basic Line Module fails, each Basic Line Module must

be selected for the full power.

· Each Basic Line Module must be able to precharge the complete common DC link capacitance.

Variant 2 with SINAMICS Basic Infeed, boundary conditions to be observed:

· If the three-winding transformer corresponds to the specification in the section “Transformers”, subsection

“Three-winding transformers”, line reactors are not required.

· If the three-winding transformer corresponds to the specification in the section “Transformers”, subsection

“Three-winding transformers”, and it can be accepted that the common DC link is operating with half the

power when a Basic Line Module fails, each Basic Line Module can be selected for half the input current

taking into account a current derating of 7.5 % related to the rated current, as with the 12-pulse, parallel

connection of Basic Line Modules. If the full infeed power is required when a Basic Line Module fails, each

of the two Basic Line Modules and their associated transformer windings must be dimensioned in line with

the full power required for the DC link.

· Each Basic Line Module must be able to precharge the complete common DC link capacitance.

Variant 3 with SINAMICS Basic Infeed, boundary conditions to be observed:

· A line reactor with a short-circuit voltage of 2 % is not required.

· Due to the possibility of large voltage tolerances between both supply systems, it is absolutely necessary

that each Basic Line Module is configured for the full power required by the common DC link.

· Each Basic Line Module must be able to precharging the complete common DC link capacitance.

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Redundant line supply concepts with the SINAMICS Smart Infeed

With the line-commutated unregulated SINAMICS Smart Infeed only variant 2 can be used.

Variant 2 with SINAMICS Smart Infeed, boundary conditions to be observed:

· Each Smart Line Module requires a line reactor with a short-circuit voltage of 4 %.

· If the three-winding transformer corresponds to the specification in the section “Transformers”, subsection

“Three-winding transformers”, and it can be accepted that the common DC link is operating with half the

power when a Smart Line Module fails, each Smart Line Module can be selected for half the input current

taking into account a current derating of 7.5 % related to the rated current, as with the 12-pulse, parallel

connection of Smart Line Modules. If the full infeed power is required when a Smart Line Module fails, each

of the two Smart Line Modules and their associated transformer windings must be dimensioned in line with

the full power required for the DC link.

· Each Smart Line Module must be able to precharge the complete common DC link capacitance.

Redundant line supply concepts with SINAMICS Active Infeed (master-slave configuration)

The regulated SINAMICS Active Infeed allows variants 2 and 3 to be realized. The individual Active Infeeds, which

comprise an Active Interface Module AIM and an Active Line Module ALM, must be configured and set up so that

they are completely autonomous. They must operat in master-slave configuration. An autonomous setup means:

· Each Active Infeed must have its own Control Unit.

· The Control Unit of each Active Infeed must control only the assigned Active Infeed but not any additional

Motor Modules.

· Due to the need for redundancy, the Motor Modules operating on the common DC link must be operated on

a separate Control Unit or multiple separate Control Units in complete independence of the Infeed Modules.

The master Infeed is operating in voltage control mode and regulates the DC link voltage VDC of the DC link, while the

slave Infeed(s) is/are operating in current control mode, whereby one master Infeed is required and not more than 3

slave Infeeds are permissible.

The current setpoint can be transferred from the master Infeed to the slave Infeed(s) by various different methods: In

systems with a higher-level controller, e.g. by PROFIBUS DP slave-to-slave communication, or in systems without a

higher-level controller via SINAMICS Link using CBE20 Communication Boards or through analog channels using

TM31 Terminal Modules. For further details about communication and parameterization, please refer to the function

manual "SINAMICS S120 Drive Functions".

If a slave Infeed fails, the master Infeed and any other slave Infeed will continue operation. If a master Infeed fails, a

slave Infeed must switch over from slave operation in current control mode to master operation in voltage control

mode. This can be done during operation (i.e. without the need for any downtime).

Variant 2 with Active Infeed (master-slave configuration); boundary conditions to be observed:

· Both of the two Active Infeeds (master and slave) must be electrically isolated on the line side to prevent

circulating currents that may otherwise occur between the systems as a result of autonomous,

unsynchronized operation with two independent Control Units. This electrical isolation, which is absolutely

essential, is ensured by means of the three-winding transformer.

Depending on the type of supply system required (grounded TN supply system or non-grounded IT supply

system), the star point of the star winding supplying the master Infeed can be grounded (TN supply system)

or remain open (IT supply system). With respect to voltage loads on the DC link and on the motor windings

to ground, however, operation with a non-grounded IT supply system is preferable. The winding for the slave

Infeed must remain non-grounded in all cases.

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· If it is acceptable to operate the DC link at half power if an Active Infeed fails, each Active Infeed can be

dimensioned for half the infeed current, taking into account a current derating of 5% with respect to the rated

current. If the full infeed power is required if an Active Infeed fails, each of the two Active Infeeds and the

associated transformer windings must be dimensioned for the full power required for the DC link.

· Each Active Line Module in conjunction with its Active Interface Module must be able to precharge the

complete common DC link capacitance.

Variant 3 with Active Infeed (master-slave configuration); boundary conditions to be observed:

· The Active Infeeds (master and slave(s)) must be electrically isolated on the line side to prevent circulating

currents that may otherwise occur between the systems as a result of autonomous, unsynchronized

operation with independent Control Units.

Depending on whether the Active Infeeds are supplied from a common low-voltage supply system or from

different medium-voltage supply systems, a distinction is made between two configurations:

a) Supply from a common low-voltage supply system:

- The master Infeed is connected directly to the low-voltage supply system, whereby the supply system

can be operated as either a grounded (TN) or non-grounded (IT) supply system. With respect to

voltage loads on the DC link and on the motor windings to ground, however, operation with a non-

grounded IT supply system is preferable.

- The slave Infeed(s) must be supplied by its / their own isolation transformer, whereby all secondary

windings must be non-grounded.

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b) Supply from different medium-voltage supply systems:

- The master Infeed is supplied via isolation transformer 1, whereby the secondary winding can be either

grounded (TN supply system) or non-grounded (IT supply system). With respect to voltage loads on

the DC link and on the motor windings to ground, however, operation with a non-grounded IT supply

system is preferable.

- The slave Infeed(s) must be supplied by its/their own isolation transformer, whereby all secondary

windings must be non-grounded.

· If it is acceptable to operate the DC link at reduced power if an Active Infeed fails, each Active Infeed can be

dimensioned for the respective proportion of the full infeed current, taking into account a current derating of

5% with respect to the rated current. If the full infeed power is required if an Active Infeed fails, each of the

Active Infeeds and associated transformers must be overdimensioned accordingly.

· The Active Line Modules that remain in operation if a fault occurs must, in conjunction with the Active

Interface Modules, be able to precharge the complete common DC link capacitance.

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1.6.7 Permissible total cable length for S120 Infeed Modules feeding multi-motor drives

General

In the case of SINAMICS S120 multi-motor drives where an S120 Infeed Module supplies a DC busbar with more

than one S120 Motor Module, not only the length of the cable between each individual Motor Module and its

associated motor is limited, but also the total cable length (i.e. the sum of the motor cable lengths for all the Motor

Modules that are fed from a common Infeed Module via a common DC busbar). Strictly speaking, the length of the

DC busbar should also be taken into account when calculating the permissible total cable length. In practice,

however, the length of the DC busbar is negligible in comparison to the total lengths of motor cables in multi-motor

drives and the DC busbar length can consequently be ignored for the purposes of this particular calculation.

The total cable length must be restricted to ensure that the resulting total capacitive leakage current Σ ILeak (sum of

the capacitive leakage currents ILeak generated from the individual Motor Modules 1 … n), which depends on the

overall motor cable length, does not overload the Infeed Module. This current is flowing back to the DC busbar via

either the line filter of the Infeed Module or the supply system and via the Infeed Module itself.

Route of the resulting total leakage current Σ ILeak for a multi-motor drive with SINAMICS S120

If the total cable length and, in turn, the total leakage current Σ ILeak are not sufficiently restricted, the integrated line

filters according to category C3 of EN 61800-3, the power components of the Infeed Module, and the snubber circuits

for the power components in the Infeed Module may be overloaded due to an excessive current or dv/dt load.

The permissible total cable lengths are device specific and are, therefore, specified in the relevant catalogs or in the

section “Checking the total cable length with multi-motor drives” of the chapter “General Information about Built-in

and Cabinet Units SINAMICS S120”.

For more information about the cause of capacitive leakage currents and their magnitude, see section “Line filters”.

EMC information

SINAMICS S120 multi-motor drives with a total cable length of several hundred meters or more generally only meet

the criteria of category C4 according to the EMC product standard EN 61800-3. This standard, however, clearly

states that this is permissible for complex systems of this type with rated currents of ³400 A used in an industrial

environment, as well as for IT supply systems. In such cases, system integrators and plant operators must define an

EMC plan, which means customized, system-specific measures to ensure compliance with the EMC requirements.

This applies regardless of whether the SINAMICS S120 multi-motor drive is operated on a grounded TN supply

system with line filters integrated in the SINAMICS Infeed Module as standard, or on a non-grounded IT supply

system with a deactivated line filter.

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1.7 SINAMICS braking units (Braking Modules and braking resistors)

Braking units consist of a Braking Module (braking chopper) and an external braking resistor and they are needed for

any system supplied by an Infeed which is not capable of regenerative operation (SINAMICS G130 and G150

converters and drives with SINAMICS S120 Basic Line Modules) and in which regenerative energy is occasionally

produced, e.g. when the drive is braking.

A Braking Module and an external braking resistor can also be used in systems with Infeeds capable of regenerative

operation (SINAMICS S150 converters and drives with SINAMICS S120 Smart Line Modules or Active Line Modules)

for applications which require the drives to be stopped after a power supply failure (e.g. emergency retraction or

EMERGENCY OFF / Category 1).

The Braking Module consists of the power electronics and the associated control electronics. When in operation, the

DC link energy is converted into heat losses by an external braking resistor outside the converter cabinet. The

Braking Module is connected to the DC link and operates completely automously as a function of the DC link voltage

value. It does not interact in any way with the closed-loop control of the Infeed or the inverter.

Braking unit comprising a Braking Module and a braking resistor

Various types of Braking Modules are available for SINAMICS converters within the power range included in this

engineering manual:

· Built-in Braking Modules (response time 1 - 2 ms),

· Central Braking Modules (response time 1 - 2 ms),

· Motor Modules which are operated as a 3-phase Braking Module (response time 4 - 5 ms).

Built-in Braking Modules are designed for mounting in SINAMICS air-cooled power units and are available with

continuous braking power ratings of 25 kW and 50 kW. They can be mounted in the Power Modules of the

SINAMICS G130, G150 and S150 converters, and in the air-cooled Line Modules and Motor Modules of the

SINAMICS S120 modular system in Chassis and Cabinet Modules format.

In order to boost the braking power, it is possible to operate multiple built-in Braking Modules on a common DC bus.

The maximum number should be restricted to between about 4 and 6 Braking Modules per DC bus in the interests of

an equal power distribution.

Central Braking Modules are stand-alone cabinet components in the spectrum of the modular SINAMICS S120

Cabinet Modules. They are available with continuous braking power ratings of 200 kW to 460 kW.

One or more Central Braking Modules can therefore be installed in drive line-ups comprising S120 Cabinet Modules

as a substitute for multiple built-in Braking Modules. In this case as well, the maximum number should be restricted to

about 4 Braking Modules per DC bus. In this regard, it is essential to observe the rules outlined in chapter "General

Information about Modular Cabinet Units SINAMICS S120 Cabinet Modules", section "Central Braking Modules".

When more than one Central Braking Module is operating on a common DC bus, a separate braking resistor must be

connected to each Central Braking Module.

SINAMICS S120 Motor Modules in Chassis and Cabinet Modules format can also be used as a Braking Module

(braking chopper) if a 3-phase braking resistor is connected instead of a motor. They are available with continuous

braking power ratings up to about 1300 kW at 400V and about 1750 kW at 690V.

The use of SINAMICS S120 Motor Modules as 3-phase Braking Modules is always advisable for applications which

require extremely high braking powers, especially high continuous braking powers.

For further information about the available range of Braking Modules, matching braking resistors and correct

matching of Power Modules plus dimensioning guidelines, please refer to the chapters on specific converter types.

The chapters "Converter Chassis Units SINAMICS G130" and "Converter Cabinet Units SINAMICS G150" also

provide examples of how to calculate the required Braking Modules and braking resistors on the basis of given load

duty cycles.

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1.8 SINAMICS Inverters or Motor Modules

1.8.1 Operating principle and properties

Inverters or Motor Modules use the DC link voltage supplied by the rectifier or the SINAMICS Infeed to generate a

variable-voltage, variable-frequency three-phase system to supply asynchronous or synchronous motors. SINAMICS

inverters are equipped with Insulated Gate Bipolar Transistors (IGBT) as power semiconductors which operate

according to the pulse-width modulation method. For further information, please refer to section "Operating principle

of SINAMICS converters".

Inverters are integral components of the SINAMICS G130 converter Chassis units and the SINAMICS G150 and

S150 converter cabinet units. They are also available as stand-alone Motor Modules in Chassis and Cabinet Modules

format in the SINAMICS S120 modular system.

SINAMICS S120 inverter or Motor Module

The maximum achievable output voltage or motor voltage is dependent on the value of the DC link voltage VDCLink

and the method of modulation used by the inverter. In vector control mode (inverter as drive object of vector type),

space vector modulation and pulse-edge modulation can be used. When space vector modulation without

overmodulation is used, the maximum achievable motor voltage is:

VMotor max SVM ≈ 0.70 • VDCLink

The maximum motor voltage achievable with pulse-edge modulation is:

VMotor max PEM ≈ 0.74 • VDCLink

The pulse frequency of the motor-side inverters of converters SINAMICS G130, G150 and S150 and for SINAMICS

S120 Motor Modules in Chassis and Cabinet Modules format has in vector control mode (drive object of vector type)

the factory settings listed in the following table.

Line supply voltage DC Link voltage Rated power Rated output current Factory setting of

pulse frequency

380 V – 480 V 3AC 510 V – 720 V DC ≤ 250 kW ≤ 490 A 2.00 kHz

≥ 315 kW ≥ 605 A 1.25 kHz

500 V – 690 V 3AC 675 V – 1035 V DC All power ratings All current ratings 1.25 kHz

Pulse frequency factory settings for SINAMICS G130, G150, S150 and S120 Motor Modules (Chassis and Cabinet Modules)

For further information about

· the permissible pulse frequency adjustment limits,

· the interrelationships between current controller clock cycle, pulse frequency and output frequency,

· how the pulse frequency affects various properties of the drive system,

· the important points to note in relation to motor-side options (motor reactors, motor filters),

· and which types of open-loop and closed-loop control are implemented in the firmware,

can be found in section "Operating principle of SINAMICS converters".

To increase the output power, up to four S120 Motor Modules can be connected in parallel. The applicable boundary

conditions are described in section "Parallel connections of converters".

SINAMICS S120 Motor Modules in Chassis and Cabinet Modules formats can also be employed as a Braking

Module (braking chopper) if a three-phase braking resistor is connected instead of a motor. For further information,

please refer to chapter "General Information about Built-in and Cabinet Units SINAMICS S120"

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1.8.2 Drive configurations with multiple Motor Modules connected to a common DC busbar

Using components of the SINAMICS S120 modular drive system, it is possible to build drive configurations for multi-

motor drives in which a S120 Infeed (Basic Infeed, Smart Infeed or Active Infeed) comprising one or up to four

parallel-connected Line Modules supplies a DC busbar with several Motor Modules.

When such drive configurations are built various aspects need to be taken into account:

· Connection of the individual Motor Modules to the DC busbar, fuse protection and precharging.

· Arrangement of the Motor Modules along the DC busbar.

· Permissible dimensions and topologies of the DC busbar.

· Short-circuit currents on the DC busbar.

· Maximum power output of the drive configuration at the DC busbar.

These aspects are described and explained in more detail below.

1.8.2.1 Connection of Motor Modules to the DC busbar, fuse protection and precharging

The DC busbar is supplied by a SINAMICS S120 Infeed that must be protected on the line side by fuses or circuit

breakers in order to provide line-side protection for the drive configuration.

The DC busbars and the DC cabling must be dimensioned such that the cross-section is sufficiently large for the

current flowing at the relevant point on the busbar. In the simplest case, the DC busbars are dimensioned over their

entire length for the maximum possible DC link current. In certain constellations, however, it is possible to reduce the

cross-section of certain sections of the DC busbar in order to save material and cut costs. When the DC busbar

design is complete, its short-circuit strength must be verified.

The DC busbar itself must be designed to attain the lowest possible inductance. This is achieved by a parallel

arrangement of positive and negative busbars with a minimum possible distance between them (although the bars

must still be separated by the necessary clearances and creepage distances).

Individual SINAMICS S120 Motor Modules can be connected to the DC busbar by three different methods.

Direct connection to the DC busbar

With this connection method, a continuous direct connection between the Motor Modules and the DC busbar is made

without separable contact points using bar conductors, cables or (in some cases) fuses.

Direct connection of a Motor Module to the DC busbar

Each Motor Module must be provided with separate fuse protection.

· Air-cooled S120 Motor Modules in Chassis format are equipped as standard for this purpose with integrated,

fast semiconductor fuses in both the positive and negative paths. These disconnect the Motor Module

quickly, reliably and completely from the DC busbar in the event of an internal short circuit.

· S120 Motor Modules in Booksize format have an integrated fuse only in the positive path. For this reason, it

is advisable to provide additional external fuse protection with fast semiconductor fuses in the positive and

negative paths.

· Liquid-cooled S120 Motor Modules in Chassis format do not feature integrated fuses. They must therefore

be connected to the DC busbar via externally mounted, fast semiconductor fuses. For the recommended

fuse types, please refer to chapter "General Information about Built-in and and Cabinet Units SINAMICS

S120".

Exception: If only a single Motor Module is supplied by a single Infeed with adapted power rating, then the same

conditions apply as with a SINAMICS G130 or G150 converter unit, i.e. the line-side fuses are sufficient to protect

both the Infeed and the Motor Module.

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All the DC link capacitance connected to the DC busbar is precharged by the precharging circuit of the SINAMICS

S120 Infeed. When the drive configuration is engineered, therefore, it is absolutely essential to check whether the

Infeeds precharging circuit is adequately dimensioned. For further information, please refer to section "Checking the

maximum DC link capacitance" in chapter "General Information about Built-in and Cabinet Units SINAMICS S120".

When directly connected to the DC busbar, all Motor Modules are supplied with DC voltage as long as the SINAMICS

S120 Infeed is in operation. With this connection variant, it is not possible to switch Motor Modules on or off

selectively, i.e. the complete drive configuration must be switched on or off.

Electromechanical connection to the DC busbar by means of a switch disconnector

For some applications, it may be necessary to disconnect the Motor Modules separately from the DC busbar. This

might be necessary in cases where special safety requirements need to be fulfilled, e.g. visible isolating distances

during servicing, or where plant sections need to be switched on or off as required. For such applications, the

modules must be connected to the busbar by means of separable contact points.

A switch disconnector is used to provide an electromechanical connection between the Motor Module and the DC

busbar. The disconnector must be wired up in a 2-pole arrangement.

Electromechanical connection of a Motor Module to the DC busbar

If the Motor Modules to be connected are equipped with integrated, fast semiconductor fuses (such as the air-cooled

Motor Modules in Chassis format), these internal fuses provide protection against internal short circuits. Therefore,

with Motor Modules of this type, the switch disconnector does not need to be fitted with any additional fuses which

means that the switch disconnector can be fitted with bar conductors.

If the Motor Modules to be connected do not feature integrated fuses (such as the liquid-cooled Motor Modules in

Chassis format), the switch disconnector must be fitted with fast semiconductor fuses, which will provide protection in

the case of internal short circuits.

These fuses are not required to protect the Motor Modules against overload, as overload protection is already

realized by the control electronics of the Motor Module.

All the DC link capacitance connected to the DC busbar is precharged by the precharging circuit of the SINAMICS

S120 Infeed. When the drive configuration is engineered, therefore, it is absolutely essential to check whether the

Infeeds precharging circuit is adequately dimensioned for the maximum possible number of Motor Modules

connected to the DC busbar. For more detailed information, refer to section "Checking the maximum DC link

capacitance" in chapter "General Information about Built-in and Cabinet Units SINAMICS S120".

With the electromechanical connection variant, individual Motor Modules may only be switched on or off when the DC

busbar is de-energized. It is not possible to switch individual Motor Modules on or off during operation due to the

absence of a precharging device, i.e. the Motor Modules can be switched on or off only when the power supply to the

entire system is disconnected and the DC link is de-energized.

Electrical connection to the DC busbar by means of a switch disconnector and a contactor assembly

If the application requires individual Motor Modules to be switched on and off selectively while the plant is in

operation, e.g. in order to disconnect defective Motor Modules from the live DC busbar, to connect standby units or

reconnect repaired units, the electrical connection must be made using a contactor assembly including precharging

device.

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With this connection variant, the Motor Modules are connected to the DC busbar by means of a switch disconnector

with fuses and a contactor with precharging device (precharging contactor with precharging resistors). The switch

disconnector and the contactors must be wired up in a 2-pole arrangement.

Electrical connection of a Motor Module to the DC bus Control of precharging contactor and contactor by the Motor

Module

Fast semiconductor fuses ensure short-circuit protection in the case of short circuits in the electrical coupling

assembly. These fuses are not required to protect the Motor Modules against overload, as overload protection is

already realized by the control electronics of the Motor Modules.

The electronic circuitry (Control Interface Module CIM) of each Motor Module controls the precharging contactor

(X9:5/6) and the contactor (X9:3/4) via connector X9 on the Motor Module, see diagram above on the right. The

precharging device, comprising precharging contactor and precharging resistors, enables the Motor Modules to be

switched on or off individually at any time while the DC busbar is energized. It is essential to set parameter p0212 /

bit 01 of the Motor Module to 1 (external precharging present) during commissioning, as described in the above

diagram on the right. This setting activates the precharging control and the precharge monitoring.

As precharging contactors DC contactors must be used, as it may be necessary to disconnect the maximum possible

precharging DC current in the event of a fault. This scenario arises, for example, if a defective Motor Module with a

short circuit in the power unit is connected to the DC busbar. In this case, a precharging DC current of the magnitude

IPrecharging = VDCLink / (2 • RPrecharging)

needs to be reliably controlled and disconnected by the precharging contactor.

As contactors, either DC contactors or, under certain boundary conditions, AC contactors can be used.

When low-cost AC contactors are used, no-load switching is an essential requirement. For this reason, the gating

pulses for the IGBTs in the Motor Modules must be disabled (pulse inhibit) when the Motor Modules are connected or

disconnected. Since no-load switching is a requirement, the system must be engineered to ensure that the contactor

cannot drop out in operation, i.e. the control voltage for the disconnector coil must be supplied by a reliable source

such as an uninterruptible power supply (UPS).

1.8.2.2 Arrangement of Motor Modules along the DC busbar

The SINAMICS S120 Motor Modules can be arranged on the DC busbar according to two basic principles:

· Arrangement according to the power rating (power rating-related sequence).

· Arrangement according to the position of the drives in the production process (process-related sequence).

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Arrangement of Motor Modules according to their power rating

The power rating-related sequence is mechanically and electrically the most convenient method of arranging the

Motor Modules along the DC busbar, i.e. they are placed to the left or right of the SINAMICS S120 Infeed in

descending order of power rating. In this case, the highest power rating is placed directly next to the Infeed, and the

lowest rating at the far end to the left or right.

The diagram below illustrates an example configuration comprising a SINAMICS S120 Infeed in Chassis format with

S120 Motor Modules in Chassis and Booksize format positioned on the right of the Infeed in descending order of

power rating.

Power rating-related arrangement of Motor Modules in drive configurations with SINAMICS S120

The power rating-related arrangement of Motor Modules is recommended because this option offers a number of

advantages afforded by the relatively small differences in mechanical dimension and electrical rating between

adjacent Motor Modules in the line:

· S120 Motor Modules in Chassis or Booksize format can be mounted adjacent to one another without any

problem, because those modules placed directly next to one another generally have similar mechanical

dimensions. In other words, only slight differences in height and depth need to be leveled out between most

types of Motor Module when they are installed in the cabinet.

· The partitioning required between Motor Modules in Chassis or Booksize format in order to ensure optimum

guidance of cooling air in the cabinet is relatively easy to implement. This is because adjacent Motor

Modules are of similar dimensions, have similar cooling air requirements and thus create similar air

pressures. As a result, relatively simple measures can be taken to prevent parasitic air circulation inside the

cabinets. For further information about cooling air guidance and partitioning, please refer to chapter "General

Engineering Information for SINAMICS", section "Cabinet design and air conditioning".

· The lower the output power rating of the connected Motor Modules, the smaller the cross-section of the DC

busbar can be, allowing significant savings on material costs in many cases. However, it is important to

ensure that the line-side fuses or the line-side circuit breaker for the S120 Infeed is capable of protecting the

entire DC busbar in the event of a short circuit.

· In the case of a serious defect in a Motor Module (caused, for example, by a defective IGBT or DC link

capacitor), generally only the fuses of the defective Motor Module will trip. This is due to the fact that Motor

Modules installed adjacent to one another have similar output ratings. The fuses of other Motor Modules in

the line remain intact.

Arrangement of Motor Modules according to the position of the drives in the production process

Some plant operators require the Motor Modules to be arranged along the DC busbar in a process-related sequence,

i.e. according to the position of the drives in the production process. The Infeed is thus placed at the beginning of the

DC busbar and the Motor Modules are arranged, irrespective of their mechanical dimensions and electrical ratings, to

correspond to the position of the drives in the production process.

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The diagram below shows an example configuration comprising a SINAMICS S120 Infeed in Chassis format at the

beginning of the DC busbar and, arranged to the right of it, S120 Motor Modules in Chassis and Booksize format in

mixed order.

Example of a process-related arrangement of Motor Modules for a drive configuration with SINAMICS S120

Arranging the Motor Modules according to the order of drives in the production process is generally unproblematic if

the following conditions are fulfilled:

· The output power ratings of the individual Motor Modules do not differ by more than about a factor of 4 to 5.

· The drive configuration consists only of Motor Modules of one type, i.e. either Chassis or Booksize format.

When these boundary conditions are fulfilled, the process-related arrangement offers practically the same

advantages as the power rating-related option by virtue of the relatively small differences in mechanical dimensions

and electrical ratings between adjacent Motor Modules.

However, in configurations in which the output power ratings of the individual Motor Modules differ by more than a

factor of 5 or Motor Modules in both, Chassis and Booksize format, are mixed in any order, a process-related

arrangement has the following disadvantages:

· Mounting S120 Motor Modules of Chassis or Booksize format in cabinets can be relatively time-consuming if

the Motor Modules positioned adjacent in the configuration have very different mechanical dimensions,

making it necessary to level out large differences in height or depth between individual Motor Modules.

· The partitioning required between the Motor Modules in Chassis or Booksize format in order to ensure

optimum guidance of cooling air in the cabinet can be relatively complicated. This is because adjacent Motor

Modules have very different dimensions and cooling air requirements and thus create wide variations in air

pressure. As a result, complicated measures are required to prevent parasitic air circulation inside the

cabinets. For further information about cooling air guidance and partitioning, please refer to chapter "General

Engineering Information for SINAMICS", section "Cabinet design and air conditioning".

· If the S120 Infeed is positioned at one end of the DC busbar and Motor Modules with very high power

outputs at the other end, then it is often necessary to dimension the cross-section of the whole DC busbar

for the full Infeed current of the S120 Infeed. The material costs for the DC busbar can be relatively high as

a result.

· In the case of a serious defect in a Motor Module with a high power rating (caused, for example, by a

defective IGBT or DC link capacitor), the fuses of a number of adjacent Motor Modules with a low power

rating might also trip in addition to the fuse of the defective Motor Module, requiring a large number of Motor

Module fuses to be replaced as a result.

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1.8.2.3 Permissible dimensions and topologies of the DC busbar

The SINAMICS S120 modular drive system is designed to be a central drive system. For this reason, the permissible

dimensions of the DC busbar including the connected Motor Modules are subject to certain limits. Thus all

components linked to the DC busbar (Infeed Modules, Motor Modules, Braking Modules) should ideally be positioned

as close as possible to one another in order to create the most compact possible drive configuration.

Experience has proven that DC busbar dimensions of up to between about 50 m and 75 m can be regarded as

noncritical for Chassis and cabinet units within the power range included in this engineering manual. Boundary

conditions requiring careful examination apply in the case of busbar dimensions ranging between about 75 m and

150 m. In this case technical clarification is generally necessary. DC busbar dimensions in excess of about 150 m as

well as star-shaped topologies in which multiple DC busbar systems are networked across multiple expanses of

100 m, are not permitted. This is because the possibility of undesirable interactions and associated system problems

cannot be ruled out in configurations of this type. Interactions can be minimized most effectively in DC configurations

which are supplied by Active Infeeds and these should be the preferred option in cases where dimensions are at the

borderline.

Examples of permissible arrangements of drive configurations for multi-motor drive systems are shown below. In all

cases, the DC busbar is supplied by an S120 Infeed which can comprise a parallel connection of up to four identical

S120 Line Modules. In these typical configurations, the Motor Modules are arranged along the DC busbar in the

recommended power rating-related sequence.

Example 1 shows a typical linear arrangement of the DC busbar, with the S120 Infeed positioned at the left-hand end

and the Motor Modules positioned to the right of the Infeed in descending order of output power rating.

Example 1: Linear arrangement of a DC busbar with the Infeed at the left-hand end of the configuration

The arrangement illustrated by example 1 is suitable for configurations in the low to medium output power range.

With higher output power ratings, a significant reduction in the load on the DC busbar and thus the required busbar

cross-section can be achieved by positioning the S120 Infeed in the center of the DC busbar and arranging the Motor

Modules in descending order of output power rating to the right and left of the S120 Infeed, as illustrated in

example 2.

Example 2: Linear arrangement of a DC busbar with Infeed in the center of the configuration

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With high power outputs in the range of a few MW for which a very long DC busbar might be required, it is better to

divide the configuration into two sub-configurations arranged back-to-back. Furthermore, if the S120 Infeed is

positioned in the center of one sub-configuration and directly connected to the center of the DC busbar of the other

sub-configuration, then very favorable dimensions of busbar cross-section can be achieved. Example 3 shows this

type of arrangement.

Motor

Module

Motor

Module

Motor

Module

Motor

Module

Motor

Module

Motor

Module

S120 Infeed

DC busbar

Motor

Module

Motor

Module

Motor

Module

Motor

Module

Motor

Module

Motor

Module

DC busbar

Motor

Module

Motor

Module

high power rating

high power rating high power rating

low power rating low power rating

Example 3: Linear arrangement of the DC busbar in two sub-configurations / back-to-back arrangement

Instead of arranging two sub-configurations back-to-back as illustrated in example 3, it is also possible to select an

arrangement with two opposite configurations as illustrated in example 4. This would allow, for example, one sub-

configuration to be mounted on one wall of the converter room and the other sub-configuration to be mounted on the

opposite wall.

Example 4: Linear arrangement of the DC busbar in two sub-configurations / opposite arrangement

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Some applications essentially require a drive configuration comprising two sub-configurations situated a long

distance apart. The sub-configurations must then be interconnected by means of long DC busbars or DC cabling, as

illustrated in example 5.

Example 5: Linear arrangement of the DC busbar in two sub-configurations installed a long distance apart

The two sub-configurations for this type of application should be no further apart than about 75 m. Basically distances

between sub-configurations of between around 75 m and 150 m are possible, but boundary conditions requiring

careful examination apply in this case. In this case technical clarification is generally necessary.

As a general rule, when the sub-configurations are spaced at the distances stated above, it is particularly important to

use a low-inductance DC busbar or DC cabling in order to eliminate the possible risk of oscillations between the sub-

configurations. These can occur in the oscillating circuit formed by the capacitances of the two sub-configurations

and the inductance of the DC busbar in cases, for example, where the resonant frequency of the oscillating circuit is

excited by system variables (such as the pulse frequencies of the Motor Modules) of the drive configuration. A low-

inductance DC busbar can be achieved by means of positive and negative bars or positive and negative cables

routed in parallel and as close as possible to one another.

Moreover, for the purpose of minimizing the risk of oscillations, it is better if the DC configuration is supplied by a

controlled Active Infeed.

Note:

There are basically three important limits which apply to the length of busbars and cables for SINAMICS S120 multi-

motor drives:

· Limitation of the length of the DC busbar. This is necessary in order to eliminate the risk of undesirable

oscillations in the system, as described above.

· Limitation of the motor cable length between each Motor Module and the associated motor. This is

necessary in order to limit the capacitive leakage currents caused by the motor cable capacitance and thus

to prevent the Motor Modules from tripping on overcurrent. For further information, please refer to section

'"Effects of using fast-switching power components (IGBTs)".

· Limitation of the total cable length, i.e. the total length of all motor cables of all Motor Modules which are

supplied by the same Infeed via a common DC busbar. This is necessary in order to prevent the total

capacitive leakage current (total of all capacitive currents produced by individual Motor Modules), which is

caused by and depending on the motor cable length, from overloading the S120 Infeed if it returns to the DC

busbar via the line filter of the S120 Infeed or the mains and the S120 Infeed itself. For further information,

refer to chapter "General Information about Built-in and Cabinet Units SINAMICS S120", section "Checking

the total cable length for multi-motor drives". Strictly speaking, the length of the DC busbar should also be

taken into account when calculating the permissible total cable length. In practice, however, the length of the

DC busbar is negligible in comparison to the total lengths of motor cables in multi-motor drives and the DC

busbar length can consequently be ignored for the purposes of this particular calculation.

1.8.2.4 Short-circuit currents on the DC busbar

A direct short circuit on the DC busbar causes spontaneous discharge of the DC links of all the S120 Infeeds and

S120 Motor Modules connected to the busbar. Since the inductance of the DC busbar is relatively low, a very high

short-circuit current develops within a very short time. Even though this current is interrupted within a few

milliseconds by the response of the DC fuses in the Motor Modules and the line-side fuses or circuit breakers of the

Infeeds, the DC busbar must still be capable to withstand the brief peak short-circuit current without impermissible

mechanical deformation or temperature rise. When the drive configuration is dimensioned, therefore, it is important to

consider the short-circuit strength of the DC busbar.

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The following tables provide guide values for the theoretically attainable contribution of individual S120 Basic Line

Modules, Smart Line Modules, Active Line Modules and individual S120 Motor Modules to the total peak short-circuit

current Ipeak short-circuit total on the DC busbar.

When only a few Line Modules and Motor Modules are connected to the DC busbar, the table values are relatively

precise so that the values stated for individual Line Modules and Motor Modules can simply be added in order to

calculate the total peak short-circuit current. As the number of Line Modules and Motor Modules connected to the DC

busbar increases, the average distance between individual S120 Modules and the short-circuit location – and thus

also the relevant inductance – increases with the result that the total peak short-circuit current decreases. When

calculating the total peak short-circuit current, it is possible to make allowance for this effect by applying the

correction factor k which is dependent on the number of Line Modules and Motor Modules connected to the DC

busbar. The approximate total peak short-circuit current on the DC busbar is therefore

Ipeak short-circuit total = k∙[sum of the peak short-circuit currents of all Line Modules and all Motor Modules……..

……..on the DC busbar according to tables]

The following applies to factor k:

o Number of Line Modules and Motor Modules < 10 k = 1.00

o Number of Line Modules and Motor Modules 10 - 20 k = 0.75

o Number of Line Modules and Motor Modules > 20 k = 0.50

With parallel connections comprising several S120 Line Modules or several S120 Motor Modules, each component of

the relevant parallel connection must be taken into account individually. In the case of a triple parallel connection of

Line Modules and a triple parallel connection of Motor Modules on one DC busbar, for example, a total of 6 Modules

needs to be included.

Basic Line Modules 380 V to 480 V 3AC Basic Line Modules 500 V to 690 V 3AC

Power

[ kW ]

Frame size Peak short-circuit current

[ kA ]

Power

[ kW ]

Frame size Peak short-circuit current

[ kA ]

200 FB 3.3 250 FB 4.5

250 FB 4.2 355 FB/FBL 6.4

360 FBL 6.0 560 FB 10.1

400 FB 6.7 630 FBL 11.3

560 GB 9.4 900 GB 16.2

600 FBL 10.0 1100 GB/GBL 19.8

710 GB 11.9 1370 GBL 24.7

830 GBL 13.9 1500 GD 27.0

900 GD 15.0

Contribution of individual S120 Basic Line Modules to the total short-circuit current on the DC busbar

Smart Line Modules 380 V to 480 V 3AC Smart Line Modules 500 V to 690 V 3AC

Power

[ kW ]

Frame size Peak short-circuit current

[ kA ]

Power

[ kW ]

Frame size Peak short-circuit current

[ kA ]

250 GX 4.2 450 GX 8.1

355 GX 5.9 710 HX 12.8

500 HX 8.4 1000 JX 18.0

630 JX 10.5 1400 JX 25.2

800 JX 13.4 -- -

Contribution of individual S120 Smart Line Modules to the total short-circuit current on the DC busbar

Active Line Modules 380 V to 480 V 3AC Active Line Modules 500 V to 690 V 3AC

Power

[ kW ]

Frame size Peak short-circuit current

[ kA ]

Power

[ kW ]

Frame size Peak short-circuit current

[ kA ]

132 FX 2.2 630 HX / HXL 11.3

160 FX 2.7 800 JX / JXL 14.4

235 GX 3.9 900 HXL 16.2

300 GX / GXL 5.0 1100 JX / JXL 19.8

380 HX / HXL 6.3 1400 JX / JXL 25.2

450 HX 7.5 1700 JXL 30.6

500 HX / HXL 8.4 -- -

630 JX / JXL 10.5 -- -

800 JX 13.4 -- -

900 JX / JXL 15.0 -- -

Contribution of individual S120 Active Line Modules to the total short-circuit current on the DC busbar

Fundamental Principles and System Description

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Motor Modules 380 V to 480 V 3AC Motor Modules 500 V to 690 V 3AC

Power

[ kW ]

Frame size Peak short-circuit current

[ kA ]

Power

[ kW ]

Frame size Peak short-circuit current

[ kA ]

110 FX / FXL 1.8 75 FX 1.4

132 FX / FXL 2.2 90 FX / FXL 1.6

160 GX / GXL 2.7 110 FX 2.0

200 GX 3.3 132 FX / FXL 2.4

250 GX / GXL 4.2 160 GX 2.9

315 HX / HXL 5.3 200 GX / GXL 3.6

400 HX / HXL 6.7 250 GX 4.5

450 HX / HXL 7.5 315 GX / GXL 5.7

560 JX / JXL 9.4 400 HX 7.2

710 JX 11.9 450 HX / HXL 8.1

800 JX / JXL 13.4 560 HX / HXL 10.1

-- - 710 JX / JXL 12.8

-- - 800 HXL 14.4

-- - 800 JX / JXL 14.4

-- - 900 JX 16.2

-- - 1000 JX / JXL 18.0

-- - 1200 JX / JXL 21.6

-- - 1500 JXL 27.0

Contribution of individual S120 Motor Modules to the total short-circuit current on the DC busbar

To dimension the DC busbar, it is first of all necessary to calculate the normal operating currents and to select the

cross-sections of the DC busbar accordingly. The total peak short-circuit current which could potentially develop in

the event of a short circuit must then be calculated. Finaly it must be verified that the selected DC busbar can

withstand the calculated peak short-circuit current. For further information about the peak short-circuit currents

permitted for the DC busbars of SINAMICS S120 Cabinet Modules, please refer to section "Required DC busbar

cross-sections and maximum short-circuit currents" in chapter "General Information about Modular Cabinet Units

SINAMICS S120 Cabinet Modules".

1.8.2.5 Maximum power rating of drive configurations at a common DC busbar

Within the scope of the SINAMICS S120 modular drive system, it is possible to build drive configurations in which a

S120 Infeed (Basic Infeed, Smart Infeed or Active Infeed) comprising one or up to four parallel-connected S120 Line

Modules supplies a DC busbar with several S120 Motor Modules. With a line voltage of 690 V, therefore, up to 6 MW

of power (4 • 1500 kW) can be fed into the busbar. The DC busbar current reaches values of up to 7500 A. The

busbar itself can extend to up to 30 m or more in length depending on the ratings of the Motor Modules and the

number of other components which might be connected (e.g. Braking Modules, dv/dt filters or output-side switches).

The system of modular, type-tested SINAMICS S120 built-in units in Chassis format and the associated system

components are capable of supplying up to 6 MW of infeed power (4 • 1500 kW) to the DC busbar with a line voltage

of 690 V, provided that the cabinet builder has dimensioned the drive configuration properly in terms of its electrical,

thermal and mechanical properties.

Adequate fuse protection for the drive configuration must be provided on the line side. The power cables and bars,

especially the DC busbar, must be dimensioned with sufficient thermal and mechanical strength to tackle with short

circuits in the system. Furthermore, to cope with ground faults in the system, PE bars must be properly dimensioned

and connections of sufficient low resistance must be provided between the S120 Chassis and the relevant cabinet

frames and between individual cabinet frames in the drive configuration. To ensure sufficient cooling, the required

flow of cooling air must be provided using air ventilation holes of adequate cross-section and using partitions for

adequate air guidance. To ensure fault-free operation, especially in large configurations of high-power drives, EMC-

compliant cable routing and shield connections must be implemented. Therefore it is absolutely essential to take care

of the following rules:

· Provide the recommended line-side protection in form of fuses or circuit breakers, and ensure that the circuit

breakers are correctly set for the relevant plant conditions.

· Observe the permissible short-circuit currents of the DC busbar.

· Provide the recommended protection for Motor Modules connected to the DC busbar.

· Comply with the required cross-sections for supply system connection, DC busbar and motor connection.

· Comply with the recommended length and topology of the DC busbar.

· Comply with the required ventilation hole cross-sections and the recommended partitioning for air-guidance.

· Provide adequate air conditioning of the electrical equipment room (cooling capacity, volumetric flow).

· Comply with the EMC installation guideline.

Fundamental Principles and System Description

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The system of modular, type-tested and system-tested SINAMICS S120 Cabinet Modules is electrically, thermally

and mechanically dimensioned to supply up to 6 MW of infeed power(4 • 1500 kW) into the DC busbar with a line

voltage of 690 V. This applies to both, to normal, fault-free operation and to fault scenarios such as short circuits and

ground faults in the system, particularly on the DC busbar. This capability essentially requires to take care of the

following rules:

· Provide the recommended line-side protection in form of fuses or circuit breakers, and ensure that the circuit

breakers are correctly set for the relevant plant conditions.

· Observe the permissible short-circuit currents of the DC busbar.

· Comply with the required cross-sections for supply system connection, DC busbar and motor connection.

· Comply with the recommended length and topology of the DC busbar.

· Provide adequate air conditioning of the electrical equipment room (cooling capacity, volumetric flow).

· Comply with the EMC installation guideline.

Fundamental Principles and System Description

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1.9 Effects of using fast-switching power components (IGBTs)

IGBTs (Insulated Gate Bipolar Transistors) are the only type of power semiconductors used in the power units of the

SINAMICS motor-side inverters. One of the characteristics of these modern power components is that they are

capable of very fast switching, minimizing the losses incurred with every switching operation in the inverter. The

inverters can thus be operated with a relatively high pulse frequency. As a result an excellent control dynamic

response can be achieved. Furthermore, it is possible to obtain a motor current which is very close to sinusoidal and

the oscillating torques and stray losses caused in the motor by converter operation remain low.

The fast switching of the IGBTs does, however, cause undesirable side effects:

· When long motor cables are used, the substantial motor cable capacitance changes polarity very quickly with

every switching operation. As a result, the inverter itself and any contactors or circuit breakers installed at the

inverter output are loaded with additional current peaks.

· The propagation time of the electromagnetic waves moving along the motor cable causes voltage spikes at the

motor terminals, thereby increasing the voltage load on the motor winding.

· The steep voltage edges at the motor terminals increase the current flow in the motor bearings.

All these effects need to be considered when the drive is configured to prevent the inverter from shutting down with

the error message "Overcurrent" before it reaches its configured output current and to protect the motor against

premature failure due to winding or bearing damage.

The individual side effects and appropriate corrective actions are discussed in more detail below.

1.9.1 Increased current load on the inverter output as a result of long motor cables

The cable capacitance of motor cables is in proportion to their length. The cable capacitance on very long motor

cables is therefore substantial, particularly if the cables are shielded or several cables are installed in parallel in the

case of drives with high power ratings.

This capacitances are charged and discharged with every switching operation of the IGBTs in the inverter, as a result

of which additional current peaks are superimposed on the actual motor current, as the diagram below illustrates.

Instantaneous values of inverter output voltage v(t) and inverter output current i(t) with long motor cables

Fundamental Principles and System Description

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The amplitude of these additional current peaks is in proportion to the cable capacitance, i.e. the cable length, and in

proportion to the voltage rate-of-rise dv/dt at the converter output in accordance with the relation

Ic Cable = CCable * dv/dt .

Although the additional current peaks occur within a period of only a few ms, the inverter must be able to provide them

for this short period in addition to the motor current. The inverter is capable of providing the peak currents up to a

specific limit of the motor cable capacitance. However, if this limit is exceeded because the motor cables are too long

or too many of them are connected in parallel, the inverter will shut down with error message "Overcurrent".

At the drive configuration stage, therefore, it is important to observe the motor cable lengths and cross-sections

specified for individual inverter units. Alternatively, additional measures have to be taken to allow the connection of

greater cable lengths and cross-sections.

For basic configurations, i.e. without motor reactors, dv/dt filters plus VPL, dv/dt filters compact plus VPL or sine-

wave filters at the inverter output, the permissible motor cable lengths which apply as standard to SINAMICS G130,

G150, S150, S120 Motor Modules (Chassis and Cabinet Modules) are listed in the table below:

Max. permissible motor cable lengths for basic configurations

Line supply voltage Shielded cable

e.g. Protodur NYCWY

Unshielded cable

e.g. Protodur NYY

380 V – 480 V 3AC 300 m 450 m

500 V – 600 V 3AC 300 m 450 m

660 V – 690 V 3AC 300 m 450 m

Permissible motor cable lengths for basic configurations of SINAMICS G130 Chassis, SINAMICS G150 and S150 cabinets

and SINAMICS S120 Motor Modules in the Chassis and Cabinet Modules format

Note:

The specified motor cable lengths always refer to the distance between inverter output and motor along the cable

route and already allow for the fact that several cables must be routed in parallel for drives in the higher power range.

The recommended and the maximum connectable cross-sections plus the permissible number of parallel motor

cables are unit-specific values. These values can be found in the unit-specific chapters of this engineering manual or

in the relevant catalogs. Where more than one motor cable is routed in parallel, please note that each individual

motor cable must contain all three conductors of the three-phase system. This helps to minimize the magnetic

leakage fields and thus also the magnetic interference on other loads. The diagram below shows an example of three

motor cables routed in parallel.

Symmetrical connection to the converter and motor of several motor cables routed in parallel

Example:

In the case of the SINAMICS G150 cabinet, 380 V to 480 V, 560 kW, Catalog D 11 recommends the routing of four

parallel cables with a cross-section each of 185 mm2 for the motor connection. According to the table above,

converter output and motor can be positioned at a distance of 300 m along the cable route when shielded cables are

used. With this constellation, therefore, 4 * 300 m = 1200 m of cable would need to be installed in order to implement

the maximum permissible cable distance of 300 m between the inverter and motor.

If the specified motor cable lengths are not sufficient for some special drive constellations, suitable measures must be

taken to allow the use of greater motor cable lengths and cross-sections. This can be achieved, for example, by using

appropriately dimensioned motor reactors which attenuate the additional current peaks and allow the connection of a

higher motor cable capacitance (see section "Motor reactors“).

Fundamental Principles and System Description

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1.9.2 Special issues relating to motor-side contactors and circuit breakers

General

Motor-side contactors and circuit breakers are not required for the majority of applications. In special cases they may

be needed, however, for example if

· a bypass circuit is provided for the converter,

· a means of disconnecting the converter from the motor must be provided for safety reasons,

· one converter is provided for multiple motors and one motor at a time is connected to the

converter.

· motors in group drives need to be individually protected against overload.

Contactors

Motor-side contactors are normally designed according to utilization category AC-3 (starting of squirrel-cage motors)

depending on the rated voltage and current ratings of the motor. For the range of power ratings of the converters and

inverters described in this engineering manual, it is not generally necessary to overdimension the contactors to

handle the capacitive charge/discharge currents associated with long motor cables.

However, switching at low output frequencies of less than around 5 Hz, which is possible in theory at the converter

output, is an issue of critical importance. Because the lower the output frequency, the longer it takes until the arc at

the contacts is interrupted by the voltage zero passage. As a result, the contacts can wear after just a few switching

operations. Switching at low output frequencies should therefore be avoided wherever possible. In applications which

do not require the contactor to operate during operation, the contactor should not be opened during operation, i.e. the

converter sequence control should always issue the pulse disable command for the inverter before the motor-side

contactor is opened.

Circuit breakers

Motor-side circuit breakers are normally designed according to the voltage and current ratings of the motor and can

be used at frequencies of up to 400 Hz. However, the following points need to be taken into account:

The response value of the instantaneous short-circuit release changes as a function of frequency. Typical reference

values are given below:

· 5 Hz: standard value according to data sheet for 50 Hz - 9 %

· 50 Hz standard value according to data sheet for 50 Hz

· 100 Hz standard value according to data sheet for 50 Hz + 10 %

· 200 Hz standard value according to data sheet for 50 Hz + 20 %

· 300 Hz standard value according to data sheet for 50 Hz + 30 %

· 400 Hz standard value according to data sheet for 50 Hz + 40 %

These changes are of only secondary importance from a practical design viewpoint, however, since the standard

response value according to the data sheet for 50 Hz corresponds to more than 10 times the rated current value.

The response value of the thermally delayed overload release can be reduced by a significant amount from the value

stated in the data sheet owing to the current harmonics associated with the pulse frequency and pulse pattern and

the capacitive charge/discharge currents which typically occur with long motor cables. This is because the thermal

overload release of circuit breakers generally consists of a bimetal strip and a heater coil which are heated as the

motor current flows through them. When the bimetal strip is deflected beyond a certain limit the circuit breaker trips.

Releases of this kind are calibrated with an alternating current of 50 Hz. The release point is thus calibrated only for

currents within the required standard range which have an rms, i.e. a thermal effect, which is identical or similar to the

calibration current. This applies to alternating currents in the 0 to 400 Hz range. The relatively high-frequency,

capacitive charge/discharge currents associated with long motor cables cause increased heating of the bimetal strip.

This is attributable in part to the induction of eddy currents and in part to the skin effect in the heater coil. Both effects

cause the thermal overload release to trip prematurely.

In consequence, motor-side circuit breakers should be selected such that the motor rated current is at the lower end

of the setting scale of the thermal overload release. This means that the circuit breaker does not need to be replaced

when corrections are necessary at the drive commissioning stage. The lower the motor output and the longer the

motor cable, the larger the setting margin will need to be.

Circuit breakers with thermal overload releases need to be overdimensioned when they are installed in group drive

systems in which a large number of low-output motors are supplied by a single high-output converter and the motors

needed to be individually protected by circuit breakers with thermal overload releases. If the motor rated currents are

within the single-digit ampere range, the circuit breakers should be sized such that the setting scale of the thermal

overload release extends to a value which equals approximately 2 to 3 times the motor rated current.

Fundamental Principles and System Description

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1.9.3 Increased voltage stress on the motor winding as a result of long motor cables

The DC link voltage VDCLink of the converter or inverter is the starting point for calculating the voltage stress between

the phases of the motor winding.

The IGBTs used in SINAMICS inverters are connecting the DC link voltage VDCLink to the inverter output with a rise

time of Tr≥ 0.1 ms. In the case of a 690 V supply with a DC link voltage of virtually 1000 V, this corresponds to a

voltage edge (phase-to-phase) with a rate-of-rise of dv/dt ≤ 10 kV/ms. The typical average values of voltage rate-of-

rise for SINAMICS are dv/dt = 3 kV/ms – 6 kV/ms. If the inverter output is connected directly to the motor cable, i.e. no

motor-side options such as motor reactors, dv/dt filters plus VPL, dv/dt filters compact plus VPL or sine-wave filters

are installed at the inverter output, this phase-to-phase voltage edge moves with a speed of about 150 m/ms (≈ half

the speed of light) along the motor cable towards the motor.

Since the impedance ZW Motor of the motor is significantly higher than the impedance ZW Cable of the motor cable, the

voltage edge arriving at the motor terminals is reflected, causing brief voltage spikes VPP in the phase-to-phase

voltage of the motor terminals which can reach values of twice the DC link voltage VDCLink.

Characteristic phase-to-phase voltage at the inverter output and motor winding when a long motor cable is used

The voltage spike due to reflection initially increases in proportion to the motor cable length and reaches its maximum

value when the rise time Tr

of the voltage edge at the inverter output is less than twice the propagation time tProp

along the motor cable, i.e. when

Cable

opr

=×< 2

2Pr

With a minimum rise time of the voltage edge of Tr = 0.1 µs and a propagation speed along the motor cable of

v ≈ 150 m/ms, the critical cable length at which the voltage spikes due to reflection can theoretically reach their

maximum value can be calculated as

Tl r

Cable 5.71.0150

1=××××>

In practice, voltage spikes due to reflection typically reach their maximum values with motor cable lengths of around

20 to 25 m and more. It is therefore true to say that in most applications where the inverter output is directly

connected to the motor cable and no motor reactors or motor filters are installed, significant voltages spikes due to

reflection must be expected at the motor.

If it is assumed that voltage spikes due to reflections will reach their maximum value with the length of motor cables

used, the absolute magnitude of the reflection-related voltage spikes VPP in the phase-to-phase voltage at the motor

is dependent on two influencing variables, i.e.

· the DC link voltage VDC Link of the inverter and

· the reflection factor r at the motor terminals.

Fundamental Principles and System Description

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The DC link voltage VDC Link of the inverter is itself depending on three influencing variables,

· the line supply voltage VLine of the drive,

· the type of Infeed (Basic Infeed / Smart Infeed or Active Infeed), and

· the operating conditions of the drive (normal motor operation or braking operation using

the VDC max controller or a braking unit).

The type of Infeed determines the relation between the DC link voltage and the line voltage.

The Basic Infeed used with G130, G150 and as S120 Basic Infeed, as well as with the S120 Smart Infeed, provides a

DC link voltage which, in normal operation, is typically higher than the line supply voltage by a factor of between 1.32

(full load) and 1.35 (partial load)

VDC Link / VLine ≈ 1.35

Active Infeeds which are used on the S150 and as S120 Active Infeed (self-commutated IGBT inverters) operate as

step-up converters and the DC link voltage always needs to be controlled to a value higher than the amplitude of the

line voltage. The ratio VDCLink / VLine must therefore always be greater than 1.42. The ratio VDCLink / VLine can be

parameterized on Active Infeeds. The factory setting is

VDC Link / VLine = 1.50

This setting should not be changed without a valid reason. Reducing the factory-set value tends to impair the control

quality while increasing it unnecessarily increases the voltage on the motor winding.

The operating conditions of the drive also influence the DC link voltage, particularly on drives with Basic Infeeds. As

these cannot regenerate energy to the power supply system, unlike Smart or Active Infeeds with regenerative

feedback capability, the DC link voltage level rises when the motor is braking. To prevent shutdown on over-voltage

in the DC link, it is often necessary to activate the VDC max controller or to use a braking unit on drives with a Basic

Infeed. Both of these mechanisms limit the rise of the DC link voltage level during braking.

The VDC max controller performs this function by manipulating the deceleration ramp. It increases the deceleration time

to a value at which the drive only generates as much braking energy as can be converted to heat by the drive power

losses.

The braking unit limits the DC link voltage level by converting the generated braking energy into heat in the braking

resistor.

The DC link voltage level which represents the activation threshold or the operating range for the VDC max controller

and the braking units is virtually identical for both mechanisms and is approximately 20 % higher than the DC link

voltage level on drives operating in motor mode with a Basic Infeed.

The reflection factor r is defined as the ratio between the peak value VPP of the phase-to-phase voltage at the motor

terminals and the DC link voltage VDCLink of the inverter:

r = VPP / VDC Link

On drives in the output power range of a few kW, the impedance ratio ZWMotor / ZWCable is so high that at maximum

reflection a reflection factor of r = 2 must be expected. However, as the drive rating increases, the impedance ratio

ZWMotor / ZWCable becomes more favorable, which means that at maximum reflection the reflection factor to be

expected on drives of > 800 kW is only r = 1.7, as illustrated by the diagram below.

Typical reflection factor at the motor terminals as a function of drive power rating

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Based on the equations and diagrams given above, the peak value VPP of the phase-to-phase voltage at the motor

winding can be exactly calculated for motor cable lengths with maximum reflection factor:

Line

DCLink

LinePP ××= .

The following tables provide an overview of the peak values VPP of the phase-to-phase voltage at the motor winding

for typical SINAMICS drive configurations as a function of the influencing variables described above for motor cable

lengths with maximum reflection factor.

The peak values VPP on the motor terminals are the lowest on drives with Basic Infeed operating in motor mode

(G130, G150, S120 Basic Line Modules) or on drives with Smart Infeed.

Line supply voltage

VLine

DC link voltage

VDCLink ≈ 1.35 * VLine

Peak voltage VPP

on motor terminals with

a reflection factor of 1.7

Peak voltage VPP

on motor terminals with

a reflection factor of 2.0

400 V 540 V 920 V 1080 V

460 V 620 V 1050 V 1240 V

480 V 650 V 1100 V 1300 V

500 V 675 V 1150 V 1350 V

600 V 810 V 1380 V 1620 V

660 V 890 V 1510 V 1780 V

690 V 930 V 1580 V 1860 V

Peak values VPP at the motor with Basic Infeed or Smart Infeed

The peak values VPP on the motor terminals are somewhat higher on drives with Active Infeeds as these operate as

step-up converters (S150, S120 Active Line Modules).

Line supply voltage

VLine

DC link voltage set to

factory value

DCLink

= 1.5

Line

Peak voltage VPP

on motor terminals with

a reflection factor of 1.7

Peak voltage VPP

on motor terminals with

a reflection factor of 2.0

400 V 600 V 1020 V 1200 V

460 V 690 V 1170 V 1380 V

480 V 720 V 1220 V 1440 V

500 V 750 V 1270 V 1500 V

600 V 900 V 1530 V 1800 V

660 V 990 V 1680 V 1980 V

690 V 1035 V 1760 V 2070 V

Peak values VPP at the motor with Active Infeed

The peak values VPP on the motor are the highest during braking when the Vdc max controller or a connected braking

unit is active. In the case of a braking unit, it is assumed that its response voltage has been adjusted according to the

line voltage, i.e. that the lower response voltage of the braking unit is selected for low line voltages. For further

details, please refer to the chapters on specific converter types, e.g. "Converter Chassis Units SINAMICS G130" and

"Converter Cabinet Units SINAMICS G150".

Line supply voltage

VLine

Response voltage

of braking unit

Peak voltage VPP

on motor terminals with

a reflection factor of 1.7

Peak voltage VPP

on motor terminals with

a reflection factor of 2.0

400 V 673 V (lower threshold) 1140 V 1350 V

460 V 774 V (upper threshold) 1320 V 1550 V

480 V 774 V (upper threshold) 1320 V 1550 V

500 V 841 V (lower threshold) 1430 V 1680 V

600 V 967 V (upper threshold) 1640 V 1934 V

660 V 1070 V (lower threshold) 1820 V 2140 V

690 V 1158 V (upper threshold) 1970 V 2320 V

Peak values VPP at the motor in braking operation with a braking unit

Fundamental Principles and System Description

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Note:

The peak values VPP at the motor specified in the tables apply to switching operations without superimposed effects.

These account for the vast majority of all switching operations. Only when very short pulses occur within the pulse

pattern generated by the inverter which is a very rare event, the peak values VPP at the motor can exceed the levels

specified in the tables by up to a maximum of 10 to 15%. Because they are so rare, these short pulses and the higher

peaks values VPP at the motor which are attributable to them are not relevant to the design of the drive system and

can therefore be ignored during the configuring process.

The peak values VPP of the phase-to-phase voltage specified in the tables combined with the value Tr (rise time of

the voltage edges), which is stated at the beginning of this section, are the basis for selecting the correct motor

insulation. They thus determine whether motors with standard insulation or special insulation are required for

converter-fed operation. This applies irrespective of whether the motors are supplied by Siemens or another

manufacturer.

For further details about Siemens standard and trans-standard motors, please refer to chapter "Motors" and to

catalog D 81.1 SIMOTICS Low-Voltage Motors.

This section of the manual will merely discuss correct selection of the motor insulation of SIMOTICS TN series

N-compact trans-standard motors when combined with SINAMICS converters, because these are the motors which

are most commonly operated on the converters described in this engineering manual and clearly demonstrate the

relationship between motor insulation and converter-fed operation.

Selection of the correct winding insulation for SIMOTICS TN series N-compact trans-standard motors

The table below shows the permissible voltage stress limits for trans-standard N-compact motors of type 1LA8, 1PQ8

and 1LL8 with standard insulation (A) and for trans-standard N-compact motors of type 1LA8, 1PQ8 and 1LL8 with

special insulation for converter-fed operation on line voltages up to 690 V (B).

Winding insulation Line supply voltage 1)

Line

Phase-to-phase1)

PP permissible

Phase-to-ground1)

PE permissible

A = standard insulation ≤ 500 V 1500V 1100 V

B = special insulation > 500 V to 690 V 2250 V 1500 V

1) Valid for SIMOTICS TN series N-compact trans-standard motors 1LA8 / 1PQ8 / 1LL8

Permissible voltage limits for SIMOTICS TN series N-compact trans-standard motors

Line supply voltage ≤ 500 V

For drives with SIMOTICS TN series N-compact trans-standard asynchronous motors of type 1LA8 / 1PQ8 / 1LL8

and line supply voltages of ≤ 500 V, motors with standard insulation and a permissible voltage rating of VPP = 1500 V

are adequate (text in blue boxes).

If we compare the peak values VPP which occur at line supply voltages of ≤ 500 V in the tables for drives with Basic

Infeeds / Smart Infeeds or Active Infeeds (text in blue boxes), then we see that these values VPP are always ≤ 1500 V

irrespective of the reflection factor.

In braking operation with a braking unit, the values VPP generally remain below the permissible upper limit of 1500 V

with line supply voltages of ≤ 500 V (text in blue boxes) only in cases where the reflection factor r < 2 with line

voltages of 460 V, 480 V and 500 V. This applies in the case of G130, G150, S150 and S120 Chassis and Cabinet

Modules due to the drive power rating of > 75 kW (according to diagram: Reflection factor as a function of drive

power rating).

Line supply voltage > 500 V to 690 V

For drives with SIMOTICS TN series N-compact trans-standard asynchronous motors of type 1LA8 / 1PQ8 / 1LL8

and line supply voltages of > 500 V, motors with special insulation and a permissible voltage rating of VPP = 2250 V

are required (text in yellow boxes).

If we compare the peak values VPP which occur at line supply voltages of > 500 V in the tables for drives with Basic

Infeeds / Smart Infeeds or Active Infeeds (text in yellow boxes), then we see that these values VPP are always

> 1500 V irrespective of the reflection factor.

In braking operation with a braking unit, the values VPP generally remain below the permissible upper limit for special

insulation of 2250 V with line supply voltages of > 500 V only in cases where the reflection factor is r < 2 with line

voltages of 690 V. This applies in the case of G130, G150, S150 and S120 Chassis and Cabinet Modules due to the

drive power rating of > 75 kW (according to diagram: Reflection factor as a function of drive power rating).

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Note:

All data in this section are applicable on the condition that the motor cables are connected directly to the inverter

output and no motor reactors, dv/dt filters plus VPL, dv/dt filters compact plus VPL or sine-wave filters are used.

Using dv/dt filters plus VPL, dv/dt filters compact plus VPL or sine-wave filters makes a critical difference to the

voltage rates-of-rise and voltage spikes on the motor and alters the conditions to such an extent that motors with

special insulation are not required. The use of these filters does however impose certain limitations and these are

described in detail in sections "dv/dt filters plus VPL and dv/dt filters compact plus VPL" and "Sine-wave filters".

Fundamental Principles and System Description

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1.9.4 Bearing currents caused by steep voltage edges on the motor

The steep voltage edges caused by the fast switching of the IGBTs in the inverter generate currents through the

internal capacitances of the motor. As a result of a variety of physical phenomena, these produce currents in the

motor bearings. In the worst-case scenario, these bearing currents can reach very high values, damage the bearings

and reduce the bearing lifetime.

In order to describe the causes of bearing currents, a block diagram of the motor with its internal capacitances as well

as the electrical equivalent circuit diagram derived from it, are shown below.

Schematic representation of the motor with its internal capacitances and the associated electrical equivalent circuit

diagram

The stator winding has a capacitance Cwh in relation to the motor housing and a capacitance Cwr in relation to the

rotor. The rotor itself has a capacitance Crh in relation to the motor housing. The bearings can be defined by

capacitances Cb which are in parallel to the capacitance Crh. This equivalent circuit diagram is valid provided that the

lubricating film is intact and so acts as electrical insulation. If the voltages at the bearings increase excessively and

cause the lubricating film to break down, the bearings starts to behave like a non-linear, voltage-dependent

resistance (not shown in the equivalent circuit diagram above).

The following diagram shows how the motor is integrated in the drive system as well as the various bearing current

types.

Integration of the motor into the drive system and representation of the various bearing current types

Spannungssprung

HF-Strom

Zirkularstrom

Rotorerdstrom

EDM-Strom

UGehäuse

UWelle

ULager

Converter

Motor

Gearbox

Motor cable

Voltage edge

HF current

Rotor shaft current

EDM current

Circular current

VHousing

VShaft

VBearing

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The circular current

In the same way as the motor cable capacitance changes its polarity with every switching edge at the inverter output,

the polarity of the capacitance Cwh between the winding and housing is also reversed with every switching edge. This

creates a kind of high-frequency, capacitive "leakage current" between the winding and the housing and thus to

ground. This leakage current leads to a magnetic imbalance in the motor which induces a high-frequency shaft

voltage VShaft. If the insulating capacity of the lubricating film on the motor bearing cannot withstand this shaft voltage,

a capacitive circular current flows through the circuit: Shaft à bearing at non-drive end (NDE bearing) à motor

housing à bearing at drive end (DE bearing) à shaft. This circular current therefore flows from the shaft to the

housing in one bearing and from the housing back to the shaft in the other. As the circular current value depends on

the capacitance Cwh between winding and housing, it increases with the shaft height of the motor. It becomes the

dominant bearing current type with motors of shaft height 225 and higher.

The EDM current

Each edge of the three phase-to-ground voltages at the winding charges or discharges the capacitance Cb of the

bearings via the capacitance Cwr between winding and rotor. The time characteristic of the voltage at the shaft and

the bearings is thus an image of the three superimposed phase-to-ground voltages at the motor winding (common

mode voltage). The magnitude of this bearing voltage is however reduced in accordance with the capacitive BVR

(Bearing Voltage Ratio) which can be calculated by the following equation

brhwr

CommonMode

Bearing

CCC

BVR 2++

The resulting voltage at the shaft and the bearings is thus determined by the common mode voltage at the winding

multiplied by the bearing voltage ratio BVR. On standard motors, this generally equals around 5 % of the common

mode voltage at the winding.

In the worst-case scenario, the bearing voltage VBearing can reach such high values that the lubricating film on the

bearing breaks down and the capacitance Cb and Crh are discharged by a short, high current pulse. This current

pulse is referred to as the EDM current (Electrostatic Discharge Machining).

The rotor shaft current

The high-frequency, capacitive "leakage current" flowing through the capacitance Cwh between winding and housing

to cause the circular current must flow from the motor housing back to the inverter. If the motor housing is badly

grounded for the purpose of high-frequency currents, the high-frequency "leakage current" encounters a significant

resistance between the motor housing and grounding system across which a relatively high voltage drop VHousing

occurs. If the coupled gearbox or driven machine is more effectively grounded for the purposes of high-frequency

current, however, the current may flow along the following path to encounter the least resistance: Motor housing via

the motor bearing – motor shaft – coupling – gearbox or driven machine to the grounding system and from there to

the inverter. With a current following this path, there is not only a risk of damage to the motor bearings, but also to the

bearings of the gearbox or the driven machine.

1.9.4.1 Measures for reducing bearing currents

Since there is a range of different bearing current types caused by different physical phenomena, it is generally

necessary to take a series of measures in order to reduce the resultant bearing currents to a non-critical level. These

measures are described in detail on the following pages.

Of the measures described, implementation of the first two is mandatory for drives within the output power range of

the SINAMICS G130, G150, S120 (Chassis and Cabinet Modules) and S150 units which supply motors of shaft

heights 225 or greater, in other words, installation in compliance with EMC requirements in order to eliminate the

rotor shaft current in combination with an insulated bearing at the non-drive end of the motor in order to eliminate the

circular current. This combination generally provides adequate protection of the bearing against damage caused by

bearing currents in virtually all applications.

All the other measures described should be regarded as supplementary and essential only in the case of extremely critical

drive constellations where it is impossible to implement an EMC-compliant installation of satisfactory standard.

If it is not practically possible to achieve EMC-compliant installation standards when extending an existing plant which

already features a poor grounding system and/or unshielded cables, it can be worthwhile to install an additional

insulating coupling in order to eliminate the rotor shaft current. With high-output low-voltage motors, it is basically also

possible to install two insulated motor bearings combined with a shaft-grounding brush and an insulating coupling, as

is normal practice for converter-fed high-voltage motors.

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1.9.4.1.1 EMC-compliant installation for optimized equipotential bonding in the drive system

The purpose of any equipotential bonding measure is to ensure that all drive system components (transformer,

converter, motor, gearbox and driven machine) stay at exactly the same potential, - i.e. at ground potential, in order

to prevent the occurrence of undesirable equalizing currents in the system.

Effective equipotential bonding is based on the grounding of all drive components by means of a well-designed

grounding system at the site of installation (protective earth PE). This grounding system should be constructed,

where possible, as a meshed network with a large number of connections to the foundation ground so as to provide

optimized equipotential bonding in the low-frequency range.

Furthermore, the entire drive system including the gearbox and the driven machine must be properly grounded with

respect to high-frequency effects (functional earth FE). This high-frequency grounding must be such that there is

effective equipotential bonding in the high-frequency range between all drive components in each drive system so

that the high-frequency currents that are inevitably generated by converter-fed drive systems are safely controlled

and directed away from the protective ground PE.

The diagram shows a complete drive plus all the major grounding and equipotential bonding measures between the

individual components of the drive.

Drive system designed with all grounding and equipotential bonding measures to reduce bearing currents

The description below explains how proper installation can reduce the inductance of connections, particularly of those

which are colored orange and red in the diagram. On the one hand, this helps to minimize the voltage drops caused

by high-frequency currents in the drive system. On the other hand, most of the high-frequency currents remain in the

drive system in which they originate and so do not have any significant impact on the protective ground PE and thus

on other drive systems and loads.

Protective grounding of the components of the drive system [0]

All electrical and mechanical drive components (transformer, converter, motor, gearbox and driven machine plus (on

liquid-cooled systems) piping and cooling system) must first be bonded with the grounding system (protective earth

PE). These bonding points are shown in black in the diagram and are made with standard, heavy-power PE cables

that are not required to have any special high-frequency properties.

In addition to these connections, the converter (as the source of high-frequency currents) and all other components in

each drive system, i.e. motor, gearbox and driven machine, must be interconnected with respect to the high-

frequency point of view. As a source of interference, the converter must be solidly bonded for high-frequency currents

with the foundation ground. These connections must be made using special cables with good high-frequency

properties.

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Optimized connection for high-frequencies between the converter and motor terminal box [2]

The connection between the converter and motor must be made with a shielded cable. For higher outputs in the

SINAMICS Chassis and cabinet unit power range, a symmetrical 3-wire, three-phase cable should be used to make

the connection whenever possible.

Shielded cables with symmetrically arranged three-phase conductors L1, L2 and L3 and an integrated, 3-wire,

symmetrically arranged PE conductor, such as the PROTOFLEX EMV-FC, type 2XSLCY-J 0.6/1 kV illustrated below

which is supplied by Prysmian, are ideal.

Shielded, symmetrically arranged three-phase cable with 3-wire PE conductor

Alternatively, it is also possible to use a shielded cable containing only three-phase conductors L1, L2 and L3 in a

symmetrical arrangement, for example, 3-wire cables of type Protodur NYCWY. In this case, the PE conductor must

be routed separately as close as possible and in parallel to the 3-wire motor cable.

For outputs in the Booksize and Blocksize unit power range, and for lower outputs in the Chassis and cabinet unit

power range, it is also possible to use shielded, asymmetrical, 4-wire cables (L1, L2, L3 plus PE) such as power

cables of type MOTION-CONNECT.

L2 L3

PE PE

L2 L3

PE PE

L1L2

ideal symmetrical 3-wire cable plus

symmetrically arranged PE conductor

symmetrical 3-wire cable with

separately routed PE conductor

asymmetrical 4-wire cable

including the PE conductor

Shielded three-phase cables with concentric shield

Effective shield bonding is achieved if EMC cable glands are used to create a solid 360° contact between the shield

and motor terminal box and, at the other side in the converter cabinet, a solid 360° contact with the EMC shield

busbar using EMC shield clips. An alternative shield connection to the PE busbar in the converter using only long,

braided "pigtails" is less suitable, particularly if the pigtails are very long, as this type of shield bond represents a

relatively high impedance for high-frequency currents. Further additional shield bonds between the converter and

motor, e.g. in intermediate terminal boxes, must never be created as the shield will then become far less effective.

EMC shield busbar

Cable fixing busbar

PE busbar

Three-phase conductors

L1 - L3

Mounting clamp

EMC shield clip

Shield

Outer sheath

PE potential

Shield bonding to the motor terminal box

using an EMC gland

Shield bonding to the EMC shield busbar in the converter

using an EMC shield clip

Motor term

inal box

EMC gland

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The shield of the shielded cable well bonded at both ends ensures optimum high-frequency equipotential bonding

between the converter and motor terminal box.

In older installations in which unshielded cables are already installed, or where the cables used have a shield with

poor high-frequency properties, or in installations with poor grounding systems, it is strongly recommended that an

additional equipotential bonding conductor made of finely stranded, braided copper wire with a large cross-section

(≥ 95 mm2) is installed between the PE busbar of the converter and the motor housing. This conductor must be

routed in parallel and as close as possible to the motor cable.

Optimized connections for high-frequencies between the motor terminal box and motor housing [3]

The electrical connection between the motor terminal box and the motor housing on some motors or motor series is

not generally designed to offer ideal high-frequency properties.

For example, flat nonconductive seals between the terminal box and housing are used on most motors with grey

cast-iron housing. This means that the electrical connection is essentially provided through a few screw points which,

even when their total effect is taken in account, do not offer an optimum, low-impedance connection for high-

frequency interference.

For this reason, the possibility of providing an additional equipotential bonding connection with good high-frequency

properties between the terminal box and motor housing must be considered. This is particularly true if the available

grounding system is poor, a problem often encountered when older installations are modernized.

This connection should be made with the shortest possible grounding cables with a large cross-section ( ≥ 95 mm2 )

and designed for low impedance over a wide frequency range. Finely stranded, braided round copper wires or finely

stranded, braided flat copper strips would be suitable for the purpose. The contact points on the terminal box and

housing must be made over the largest possible area, treated carefully to remove paint or varnish and have good

conducting properties.

The following photographs show a selection of suitable cables.

Finely stranded, braided round copper wires Finely stranded, braided flat copper strips

On motors which are constructed with a large-area, adequately conductive connection between the terminal box and

housing, no additional connection is required and can be omitted. Siemens SIMOTICS M compact asynchronous

motors in series 1PL6, 1PH7 and 1PH8 as well as SIMOTICS FD motors feature a connection of this kind as they are

specially designed for converter-fed operation.

Optimized connection for high-frequencies between motor housing, gearbox and driven machine [4], [5]

A further equipotential bonding measure is to link the motor housing to the gearbox and the driven machine in a

conductive connection with good high-frequency properties. A lead made of finely stranded, braided copper cable

with a large cross-section (≥ 95 mm2) should also be used for this purpose.

Optimum high-frequency bond between converter and foundation ground [6]

As a final equipotential bonding measure, the converter must be solidly bonded for high-frequency currents with the

foundation ground. A lead made of finely stranded, braided copper cable with a large cross-section (≥ 95 mm2)

should also be used for this purpose.

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Overview of grounding and equipotential bonding measures

The following diagram illustrates all grounding and high-frequency equipotential bonding measures using the

example of a typical installation comprising several SINAMICS S120 Cabinet Modules.

Grounding and high-frequency equipotential bonding measures for reducing bearing currents

The ground connections shown in black [0] represent the conventional protective grounding system (PE) for the drive

components. They are made with standard, heavy-power PE conductors without special high-frequency properties

and ensure low frequency equipotential bonding as well as protection against injury.

The connections shown in red inside the SINAMICS cabinets [1] provide solid bonding for high-frequency currents

between the metal housings of the integrated Chassis components and the PE busbar and the EMC shield busbar of

the cabinet. These internal connections can be made via a large area using non-isolated metal construction

components of the cabinet. In this case, the contact surfaces must be bare metal and each contact area must have a

minimum cross-section of several cm2. Alternatively, these connections can be made with short, finely stranded,

braided copper wires with a large cross-section (≥ 95 mm2).

The shields of the motor cables shown in orange [2] provide high-frequency equipotential bonding between the Motor

Modules and the motor terminal boxes. In older installations in which unshielded cables are already installed, or

where the cables used have a shield with poor high-frequency properties, or in installations with poor grounding

systems, it is absolutely essential to install the finely stranded, braided copper cables shown in red in parallel and as

close as possible to the motor cable.

The connections shown in red [3], [4] and [5] provide a conductive, high-frequency bond between the terminal box of

the motor and the motor housing, and also between gearbox / driven machine and the motor housing. These

connections can be omitted if the motor is constructed in such a way that a conductive, high-frequency bond is

provided between the terminal box and the housing, and if motor, gearbox and driven machine are all in close

proximity and all conductively bonded over a large area by means of a shared metallic structure, e.g. a metal

machine bed.

The connections shown red dashed-and-dotted lines [6] provide a conductive, high-frequency bond between the

cabinet frame and the foundation ground in the form of finely stranded, braided copper cables with large cross-

section ( ≥ 95 mm 2).

The equipotential bonding measures described above can practically eliminate the rotor shaft currents. It is therefore

possible to dispense with insulating couplings between the motor and gearbox / driven machine. This is always an

advantage in cases where insulating couplings cannot be used for any number of reasons.

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1.9.4.1.2 Insulated bearing at the non-drive end (NDE) of the motor

Apart from an EMC-compliant installation which essentially prevents rotor ground current, the use of a motor with an

insulated bearing at the non-drive end (NDE) is the second most important measure for reducing bearing currents.

Essentially, the insulated NDE bearing reduces the capacitive circular current in the motor by significantly increasing

the impedance in the circuit comprising the shaft – NDE bearing – motor housing – DE bearing – shaft. Since the

circular current increases in proportion to the motor shaft height, it is particularly important to install an insulated NDE

bearing on large motors.

Insulated bearings at the non-drive end are available for SIMOTICS SD series 1LG standard motors of shaft height

225 and larger as an option (order code L27) and this option is strongly recommended if these motors are to be fed

by converters. All SIMOTICS TN series N-compact trans-standard motors of types 1LA8, 1PQ8 and 1LL8 which are

designed for converter-fed operation ("P" in the 9th position of the article number, e.g. 1LA8315-2PM80) are

equipped as standard with insulated non-drive end bearings.

SIMOTICS M compact asynchronous motors series 1PL6, 1PH7 and 1PH8 in frame size 180 and larger are

optionally available with insulated non-drive end bearings (order code L27). These compact asynchronous motors are

equipped as standard with insulated non-drive end bearings in frame size 225 and larger.

In systems with speed encoders, it must be ensured that the encoder is not installed in such a way that it bridges the

bearing insulation, i.e. the encoder mounting must be insulated or an encoder with insulated bearings must be used.

1.9.4.1.3 Other measures

Motor reactors or motor filters at the converter output

Installation in compliance with EMC guidelines and the use of a motor with an insulated NDE bearing is sufficient in

practice for virtually all applications to limit bearing currents to a non-critical level, even under worst-case conditions

when stochastic disruptive discharges attributable to the EDM effect occur in the bearing.

Only in exceptional cases it might be necessary to take additional measures for further reduction of bearing currents.

This can be achieved with common mode filters consisting of toroidal cores made of highly permeable magnetic

material. They are mounted at the converter output and enclose all three phases of the motor cable. These common

mode filters reduce bearing currents of the kind caused by common mode currents, i.e. circular currents and rotor

ground currents. By contrast, the cores have virtually no effect in counteracting voltage-induced EDM currents.

Since it is normally not necessary to use common mode filters for SINAMICS drives, these are not available as a

standard option but only on request.

As a general rule, all measures implemented at the converter output which serve to reduce the voltage rate-of-rise

dv/dt have a positive impact on bearing current levels in the motor.

Motor reactors reduce the voltage rate-of-rise on the motor as a function of the motor cable length. Although they

help basically to reduce bearing currents, they cannot be regarded as a substitute to EMC-compliant installation and

the use of motors with insulated NDE bearings.

The capability of dv/dt filters plus VPL, dv/dt filters compact plus VPL and sine-wave filters to reduce the voltage

rates-or-rise on the motor is generally not affected by the motor cable length and achieves dv/dt values lower than

those obtained with motor reactors. The values attained with sine-wave filters in particular are markedly lower.

In consequence, it is possible to dispense with insulated motor bearings when dv/dt filters, or more particularly, sine-

wave filters are installed at the output of SINAMICS converters.

Grounding of the motor shaft with a grounding brush

Shaft-grounding brushes can reduce bearing currents because the brushes short the bearing. Various types of

grounding brushes are available. In addition to graphite brushes, carbon-fiber-based systems are also available, but

are extremely expensive by comparison with graphite brushes. Although they suffer less wear, their condition is

heavily dependent on the prevailing ambient conditions. For this reason, these brushes are not recommended for use

in general industrial applications.

Shaft-grounding brushes are one possible – but not a particularly effective – means of reducing bearing damage

caused by voltage-induced EDM currents. In the case of bearing damage caused by circular and/or rotor shaft

currents these brushes tend to be counterproductive. With respect to rotor shaft currents in particular, the parasitic

current flowing into the load (e.g. gear box) has the tendency to increase further. While the motor bearing itself is

protected, there is a greater risk of damage to the downstream components of the drive system (e.g. gear box). For

these reasons, shaft-grounding brushes are better suited to applications in the low power range in which EDM current

components predominate.

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However, there are also problems associated with shaft-grounding brushes. They are very difficult to construct for

smaller motors, they are sensitive to contamination and also require a great deal of maintenance. Shaft-grounding

brushes are not therefore generally recommended as a solution for reducing bearing currents in low-voltage motors.

Electrically conductive bearing greases

State-of-the-art, electrically conductive bearing greases available on the market today are completely ineffective in

protecting bearings against damage caused by voltage-induced EDM currents. Indeed, there is a risk that they will

increase the current-related bearing currents (circular and rotor shaft currents). The use of electrically conductive

greases is not therefore currently regarded as a viable method of reducing bearing currents.

IT system

In operation on an IT system, the transformer neutral is not electrically connected to ground as it is with TN systems.

The ground connection is purely capacitive in nature, causing the impedance to increase in the circuit in which high-

frequency, common mode currents are flowing. The result is a reduction in the common mode currents and thus also

in the bearing currents. With respect to bearing currents, therefore, non-grounded IT systems are more beneficial

than grounded TN systems.

1.9.4.2 Summary of bearing current types and counter-measures

The following overview shows the different types of bearing currents depending on the shaft height and the grounding

conditions of stator and rotor.

Dominant bearing current types dependent on the shaft height and the grounding conditions of stator and rotor

Rotor grounding Stator grounding

Shaft height

Rotor shaft currents

Counter measure:

EDM currents

Counter measure:

Circular currents

Counter measure:

yes

EDM currents without superimposed

circular and rotor shaft currents have a

tolerable magnitude. Therefore, usually

no measures are required.

§Isolated bearing on the NDE of the

motor (NDE = Non-Drive End)

or, alternatively

§dv/dt filter or sinusoidal filter at the

output of the converter / inverter

(dv/dt phase to ground < 0.5 kV/ms)

Good rotor grounding achieved through

conductive coupling to the well-grounded

driven machine?

Good stator grounding through

•shielded, symmetrical motor cable?

and

•shield connected on both sides and with a large surface area?

and

•HF potential bonding between motor housing and driven machine?

From shaft heights of ≥ 225 also recommended:

•

HF potential bonding between motor terminal box and housing?

yes

•shielded, symmetrical motor cable

shield (connected on both sides)

•HF potential bonding between motor

housing and driven machine

From shaft heights ≥225 recommended

•HF potential bonding between motor

terminal box and motor housing

SH ≤ 100

100 < SH < 225

SH ≥ 225

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If the rotor is well grounded via a conductive coupling and a well-grounded driven machine or load but the stator is

poorly grounded due to unsatisfactory installation, the rotor grounding currents become dominant which, in turn, can

quickly damage the bearings of the motor and driven machine or load. These situations must be avoided absolutely

by ensuring that the stator is properly grounded in an EMC-compliant installation and/or by means of an insulating

coupling.

If, by means of a well grounded stator with an EMC-compliant installation and/or an insolating coupling, the

occurrence of rotor shaft currents is prevented, EDM currents are dominant in smaller motors with shaft heights of up

to 100. Circular currents play a secondary role here. So the resulting bearing currents are on a low-risk level for the

bearings and no further measures usually need to be taken. As the shaft height increases, the EDM currents change

slightly, while the circular currents continually increase. From shaft heights of 225 the circular currents become

dominant and critical for the bearings. Therefore, from shaft heights of 225, the use of an isolated bearing on the

NDE of the motor is very highly recommended. This applies in particular if the motor is operated frequently or

continuously

· at low speeds below approximately 800 – 1000 rpm, or is required to operate

· at speeds that change very quickly,

because an even, stable lubricating film cannot develop in the bearing under these operating conditions.

Basically a dv/dt filter or a sinusoidal filter can also be used at the output of the converter, as alternative to an isolated

bearing in the motor.

The measures to be implemented on the motor in order to prevent bearing current damage are illustrated graphically

below.

1. Standard measures for the SINAMICS drives described in this engineering manual

1.1 Drive with one motor

o Good equipotential bonding due to EMC-compliant installation

o Insulated bearing at NDE of motor

1.2 Drive with two motors in tandem arrangement

o Good equipotential bonding due to EMC-compliant installation

o Insulated bearings at NDEs of motors

o Insulating coupling between the two motors

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1.10 Motor-side reactors and filters

1.10.1 Motor reactors

1.10.1.1 Reduction of the voltage rate-of-rise dv/dt at the motor terminals

As described in detail in the section "Effects of using fast-switching power components (IGBTs)", very high voltage

rate-of-rise dv/dt occurs at the inverter output and the motor terminals.

This rate-of-rise can be reduced through the use of motor reactors.

In systems without motor reactors, the voltage edges at the inverter output which have a rate-of-rise dv/dt of typically

3 kV/ms – 6k V/ms, move along the cable towards the motor and reach the motor terminals with a virtually unchanged

rate-of-rise. The resultant voltage reflections cause voltage spikes which can reach up to twice the DC link voltage,

see Figure a) in diagram below.

As a result, the motor winding is subjected in two respects to a higher voltage stress than would normally be imposed

by a sinusoidal supply. The voltage rate-of-rise dv/dt is very steep and the voltage spikes VPP caused by the

reflection are also very high.

a) without motor reactor b) with motor reactor

Voltage v(t) at the inverter output and at the motor terminals

When motor reactors are installed, the reactor inductance and the cable capacitance are forming an oscillating circuit

which reduces the voltage rate-of-rise dv/dt. The higher the cable capacitance is, i.e. the longer the cable is, the

greater the reduction in the rate-of-rise. When long, shielded cables are used, the voltage rate-of-rise drops to just a

few 100 V/ms, see Figure b) in diagram. Unfortunately, however, the oscillating circuit built by the reactor inductance

and the cable capacitance is relatively weakly damped so that severe voltage overshoots occur. If a motor reactor is

installed, the voltage peaks at the motor terminals are therefore typically only around 10 % to maximum 15 % lower

than those produced by reflections without motor reactor..

While the motor reactor significantly reduces the voltage rate-of-rise dv/dt, it dampens the voltage spikes VPP to only

a limited extent, and the difference in the quality of the voltage stress by comparison with systems without a motor

reactor is therefore only minimal.

As a result, the use of a motor reactor is not generally a suitable solution for reducing the voltage stress on the motor

winding with line supply voltages of 500 V to 690 V to such an extent that it is possible to dispense with special

insulation in the motor. This level of improvement can be achieved only by means of dv/dt filters plus VPL, dv/dt filters

compact plus VPL or sine-wave filters (see sections "dv/dt filters plus VPL and dv/dt filters compact plus VPL", and

"Sine-wave filters").

Although the reduction of the voltage rate-of-rise attenuates the bearing currents in the motor, this is not sufficient to

completely obviate the need for an insulated NDE bearing in the motor.

1.10.1.2 Reduction of additional current peaks when long motor cables are used

As a result of the high voltage rate-of-rise of the fast-switching IGBTs, the cable capacitance of long motor cables

changes polarity very quickly with every switching operation in the inverter, thereby loading the inverter output with

high additional current peaks.

The use of motor reactors reduces the magnitude of these additional peaks because the cable capacitance changes

polarity more slowly due to the reactor inductance, thereby attenuating the amplitudes of the current peaks.

Suitably dimensioned motor reactors or series connections of motor reactors therefore offer a solution which allows a

higher capacitance and thus also longer motor cables to be connected.

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1.10.1.3 Permissible motor cable lengths with motor reactor(s) for single- and multi-motor drives

Permissible motor cable lengths for drives with one motor (single-motor drives)

The tables below specify the permissible motor cable lengths in systems with one motor reactor or two series-

connected motor reactors for SINAMICS G130, G150 and S150, S120 Motor Modules (Chassis and Cabinet

Modules).

SINAMICS G130 / G150 Maximum permissible motor cable length

with 1 reactor with 2 series-connected reactors

Line supply voltage Shielded cable

e.g. Protodur

NYCWY

Unshielded cable

e.g. Protodur

NYY

Shielded cable

e.g. Protodur

NYCWY

Unshielded cable

e.g. Protodur

NYY

380 V – 480 V 3AC 300 m 450 m 450 m 675 m

500 V – 600 V 3AC 300 m 450 m 450 m 675 m

660 V – 690 V 3AC 300 m 450 m 450 m 1) 675 m 1)

1) For SINAMICS G150 parallel converters with outputs from 1750 kW to 2700 kW, the values are: 525 m (shielded) and 787 m (unshielded)

Maximum permissible motor cable lengths with 1 or 2 motor reactors for

SINAMICS G130 Chassis and SINAMICS G150 cabinets

SINAMICS S120 / S150 Maximum permissible motor cable length

with 1 reactor with 2 series-connected reactors

Line supply voltage Shielded cable

e.g. Protodur

NYCWY

Unshielded cable

e.g. Protodur

NYY

Shielded cable

e.g. Protodur

NYCWY

Unshielded cable

e.g. Protodur

NYY

380 V – 480 V 3AC 300 m 450 m 525 m 787 m

500 V – 600 V 3AC 300 m 450 m 525 m 787 m

660 V – 690 V 3AC 300 m 450 m 525 m 787 m

Maximum permissible motor cable lengths with 1 or 2 motor reactors for SINAMICS S150 cabinets

and SINAMICS S120 Motor Modules in the Chassis and Cabinet Modules format

Note:

The specified motor cable lengths always refer to the distance between inverter output and motor along the cable

route and already allow for the fact that several cables must be routed in parallel for drives in the higher power range.

The recommended and the maximum connectable cross-sections plus the permissible number of parallel motor

cables are unit-specific values. These values can be found in the unit-specific chapters of this engineering manual or

in the relevant catalogs.

Permissible motor cable lengths for drives with several motors at the converter output (multi-motor drives)

Normally a single motor is connected to the converter output. There are however applications such as roller drives or

gantry drives on container cranes which require a large number of identical, low-power-output motors to be supplied

by a single converter of sufficiently high output rating. This type of configuration is referred to as a "multi-motor drive".

Within the narrower context of the calculation procedure described below, the term "multi-motor drive" always applies

if the number of motors connected to the converter output is higher than the maximum permissible number of parallel

motor cables specified in the catalog.

Motor reactors (or motor filters) must always be installed for multi-motor drives. The individual motors are connected

by cables of very small cross-section due to their low power rating. The capacitance per unit length of these cables is

significantly lower than that of the large cross-section cables used for single-motor drives. As a result of this reduced

capacitance per unit length, the total permissible cable lengths per converter output for multi-motor drives can exceed

the values specified in the above tables by a significant amount without violating the maximum permissible

capacitance values stipulated for the converter and motor reactor.

Fundamental Principles and System Description

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A method of calculating the permissible cable lengths for multi-motor drives lM based on the catalog data for single-

motor drives is described below.

The diagram explains the quantities and terms used for both single-motor and multi-motor drives.

Block diagram of single-motor drive and multi-motor drive with relevant quantities and terms

The permissible motor cable length per motor on a multi-motor drive is calculated with the fomula:

)(

)()( maxmaxmaxmax

ACn

lACnlACn

DDDSSS

M×

Definition and meaning of applied quantities:

· l

MPermissible cable length between the subdistributor and each motor in a multi-motor drive.

· n

S max Maximum number of motor cables which can be connected in parallel in a single-motor drive. This

value can be found in the chapters on specific units or in the relevant catalogs.

· C

S max(Amax) Capacitance per unit length of a shielded motor cable with the maximum permissible cross-section

Amax for a single-motor drive. This value can be found in the table on the next page and is

depending on the maximum permissible cross-section Amax specified in the chapters on specific

units or the relevant catalogs.

· l

S max Permissible motor cable length for single-motor drive as specified in the tables on the previous

page (depending on the number of motor reactors (1 or 2) and whether the cable is shielded or

unshielded).

· n

DNumber of parallel cables between the converter and subdistributor on a multi-motor drive.

· C

(A) Capacitance per unit length of the cable between the converter and subdistributor on a multi-motor

drive.

· l

DLength of the cable between the converter and subdistributor on a multi-motor drive.

· n

MNumber of parallel cables on motor side of subdistributor = number of motors.

· C

(A) Capacitance per unit length of cables on motor side of subdistributor.

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The calculation formula given above allows for arrangements in which a large-cross-section cable is taken from the

converter to a subdistributor to which motors are connected by small cross-section cables, as well as arrangements

in which the cables to individual motors are directly connected to the converter. In systems without a subdistributor,

the term nD * CD(A) * lD must be set to "0".

The formula is valid for converters and inverters with one or two motor reactors at the output and for shielded and

unshielded motor cables. Allowance for the number of motor reactors (1 or 2) and the cable type (shielded or

unshielded) is made exclusively by the value lS max, which is specified according to the configuration to be calculated

in the relevant columns of the tables two pages above. It must however be taken into account that this formula is not

suitable for calculating mixtures of shielded and unshielded cables, e.g. in cases where a shielded cable is used up to

the subdistributor and unshielded cables to the motor.

Since only the ratio of capacitance values of motor cables with different cross-sections is relevant in the formula

rather than the absolute capacitance value itself, the capacitance per unit length values for cable type Protodur

NYCWY stated in the table below as a function of the cable cross-section can be applied for all shielded and

unshielded cable types for the purposes of this calculation.

Cross-section A

[mm2]

Capacitance per unit length

[nF/ m]

3 x 2.5 0.38

3 x 4.0 0.42

3 x 6.0 0.47

3 x 10 0.55

3 x 16 0.62

3 x 25 0.65

3 x 35 0.71

3 x 50 0.73

3 x 70 0.79

3 x 95 0.82

3 x 120 0.84

3 x 150 0.86

3 x 185 0.94

3 x 240 1.03

3 x 300 1.10

3 x 350 1.15

3 x 400 1.20

Capacitance per unit length of shielded, three-wire, motor cables

of type Protodur NYCWY as a function of the cable cross-section A

Calculation example:

A roller table with 25 motors, each with an output power rating of 10 kW, is to be supplied by a SINAMICS G150

converter. A converter with a supply voltage of 400 V and an output power of 250 kW is selected for this application.

The roller table application data are as follows:

The converter is sited in an air-conditioned room and will supply a subdistributor via two parallel, shielded cables,

50 m in length, each with a cross-section of 150 mm2. 25 motors are connected to the subdistributor via shielded

cables, each on average 40 m in length with a cross-section of 1 x 10 mm2.

Since this is a multi-motor drive with a large number of parallel motor cables, it is absolutely essential to install a

motor reactor. We shall now use a calculation to check whether the selected converter combined with a motor reactor

can fulfill the requirements.

1st step:

Calculation of the quantities nS max, CS max(Amax) and lS max for single-motor drives from the data given in the chapter

"Converter Cabinet Units SINAMICS G150” or the specifications in Catalog D11 by applying the information in the

above table of capacitance per unit length as a function of the cable cross-section:

According to Catalog D 11, a maximum of two parallel motor cables, each with a maximum cross-section of 240 mm2

can be connected to the motor terminals of converter type SINAMICS G150 / 400 V / 250 kW. The maximum motor

cable length for shielded motor cables in combination with one motor reactor is 300 m according to Catalog D 11.

From this data we can calculate:

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· n

S max = 2

· C

S max(Amax) = CS max(240 mm2) = 1.03 nF/m

· l

S max = 300 m

2nd step:

Calculation of quantities nD, CD(A) and lD for the cable between the converter and subdistributor:

· n

D= 2

· C

(A) = CD(150 mm2) = 0.86 nF/m

· l

D= 50 m

3rd step:

Calculation of quantities nM, CM(A) for the cable between the subdistributor and each motor:

· n

M= 25

· C

(A) = CM(10 mm2) = 0.55 nF/m

4th step:

Calculation of the permissible motor cable length between the subdistributor and each motor using calculation

formula:

mnF

mmnFmmnF

lM/.

/./.

55025

5086023000312

××-××

mmm

nFnF

lM40738

7513

86618 »=

The required cable length of 40 m per motor is within a 10 % tolerance band around the calculated value lM =38.7 m

which means that the arrangement can be implemented as planned.

If we compare the maximum cable distance of 600 m which may be connected to the converter for a single-motor

drive (two parallel cables, each 300 m in length and each with a cross-section of 240 mm2) and the cable distance of

1068 m for the multi-motor drive (two parallel cables, each 50 m in length and each with a cross-section of 150 mm2

to the subdistributor plus 25 parallel cables to the motors, each 38.7 m in length and with a cross-section of 10 mm2),

we can see that the reduction in cross-section for the multi-motor drive nearly doubles the maximum permissible

cable distance allowed for single-motor drives, even though the total capacitance is the same.

1.10.1.4 Supplementary conditions which apply when motor reactors are used

With the cabinet units G150 and S150 as well as with the S120 Motor Modules in Cabinet Modules format, it must be

noted that an additional cabinet may be required if two reactors are connected in series.

It must be noted that the motor reactor should be mounted close the converter or inverter output in the case of

SINAMICS G130 and S120 units in Chassis format. The cable length between the converter or inverter output and

the motor reactor should not exceed 5 m.

When motor reactors are installed, the pulse frequency and the output frequency must be limited for thermal reasons:

· The maximum pulse frequency is limited to twice the factory setting value, i.e. to 4 kHz for units with

factory setting 2 kHz and to 2.5 kHz for units with factory setting 1.25 kHz.

· The maximum output frequency is limited to 150 Hz.

No limits apply with respect to the permissible pulse patterns of the gating unit, i.e. pulse-edge modulation can be

used without restriction, which means that the attainable output voltage is virtually equal to the input voltage.

The voltage drop across the motor reactor is about 1 %.

As part of the drive commissioning process, the motor reactor should be selected with parameter setting P0230 = 1

and the reactor inductance entered in parameter P0233. This ensures that optimum allowance will be made for the

effect of the reactor in the vector control model.

Motor reactors can be used in both grounded systems (TN/TT) and ungrounded systems (IT).

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1.10.2 dv/dt filters plus VPL and dv/dt filters compact plus VPL

1.10.2.1 Design and operating principle

The dv/dt filters plus VPL and dv/dt filters compact plus VPL consist of two components, i.e. a dv/dt reactor and a

voltage limiting network (Voltage Peak Limiter).

The dv/dt reactor achieves the same effect as the motor reactor. In combination with the capacitance of the

connected motor cable and the internal capacitance of the limiting network, it forms an oscillating circuit which limits

the voltage rate-of-rise dv/dt to the following values irrespective of the length of the connected motor cable:

· dv/dt < 500 V/ms with dv/dt filters plus VPL

· dv/dt < 1600 V/ms with dv/dt filters compact plus VPL

The limiting network basically comprises a diode bridge and connects the output of the dv/dt reactor to the inverter

DC link. By this arrangement, the voltage overshoots at the dv/dt reactor output are limited to approximately the level

of the DC link voltage, and the peak voltage ÛLL on the motor cable is thus restricted accordingly. Due to the reduced

voltage gradient, the voltage conditions at the output of the dv/dt filter and the motor terminals are practically

identical.

a) without dv/dt filter b) with dv/dt filter plus VPL or dv/dt filter compact plus VPL

Voltage characteristic v(t) at the inverter output and at the motor terminals

dv/dt filters plus VPL and dv/dt filters compact plus VPL are very effectively limiting both the voltage rate-of-rise dv/dt

and the peak voltage VPP on the motor winding to the values given below.

· dv/dt filter plus VPL:

· Voltage rate-of-rise dv/dt < 500 V/ms

· Peak voltage VPP (typically) < 1000 V for VLine < 575 V

· Peak voltage VPP (typically) < 1250 V for 660 V < VLine < 690 V

· dv/dt filter compact plus VPL:

· Voltage rate-of-rise dv/dt < 1600 V/ms

· Peak voltage VPP (typically) < 1150 V for VLine < 575 V

· Peak voltage VPP (typically) < 1400 V for 660 V < VLine < 690 V

Fundamental Principles and System Description

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The dv/dt filter plus VPL is capable of limiting the peak voltage to values below the limit curve stipulated in

IEC/TS 60034-17:2006 (VPP < 1350 V), and the dv/dt filter compact plus VPL is capable of limiting the peak voltage to

values below the limit curve A stipulated in IEC/TS 60034-25:2007 (VPP<1560 V).

The use of dv/dt filters plus VPL and dv/dt filters compact plus VPL is thus a suitable method of reducing the voltage

stress on the motor winding at line supply voltages of 500 V to 690 V to such an extent that special insulation in the

motor can be dispensed with. Bearing currents are also reduced significantly. Using these filters therefore allows

standard motors with standard insulation and without insulated bearing to be operated on SINAMICS up to line

supply voltages of 690 V. This applies to both Siemens motors and motors supplied by other manufacturers.

The table below specifies the permissible motor cable lengths for dv/dt filters plus VPL and dv/dt filters compact plus

VPL for SINAMICS G130, G150, S150 and S120 Motor Modules in Chassis and Cabinet Modules format.

Maximum permissible motor cable length

Line supply voltage Shielded cable

e.g. Protodur NYCWY

Unshielded cable

e.g. Protodur NYY

du/dt-Filter plus VPL

380 V – 480 V 3AC 300 m 450 m

500 V – 600 V 3AC 300 m 450 m

660 V – 690 V 3AC 300 m 450 m

du/dt-Filter compact plus VPL

380 V – 480 V 3AC 100 m 150 m

500 V – 600 V 3AC 100 m 150 m

660 V – 690 V 3AC 100 m 150 m

Maximum permissible motor cable lengths with dv/dt filters plus VPL and dv/dt filters compact plus VPL

for SINAMICS G130, G150, S150 and SINAMICS S120 Motor Modules (Chassis and Cabinet Modules)

These cable lengths apply to drives on which only one motor is connected to the filter output. Longer motor cable

lengths can be used for drives with multiple motors at the filter output. Please refer to section "Motor reactors" for

information on how to calculate the permissible motor cable lengths drives with multiple motors. If this calculation

method is used for converters with dv/dt filters, it has to be taken in account that instead of the maximum number of

parallel cables nS max and the maximum cross-sections Amax the relevant recommended values nS rec and Arec from

the catalog have to be used.

1.10.2.2 Supplementary conditions which apply when dv/dt-filters are used

On G150 and S150 cabinet units and S120 Motor Modules in Cabinet Modules format, please note the following:

· Above certain output power ratings, dv/dt filters plus VPL require an additional cabinet panel and thus increase

the cabinet dimensions (see Catalogs D 11 and D 21.3).

· dv/dt filters compact plus VPL can generally be integrated into cabinet units without the need for an additional

cabinet panel.

It must be noted that the dv/dt filter plus VPL or dv/dt filter compact plus VPL should be mounted close to the

converter or inverter output in the case of SINAMICS G130 and S120 units in Chassis format. The cable length

between the filter and the output of the converter or inverter should not exceed 5 m.

Fundamental Principles and System Description

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The pulse frequency and output frequency must be limited for thermal reasons when dv/dt filters plus VPL and dv/dt

filters compact plus VPL are used:

· The maximum permissible pulse frequency is limited to twice the factory setting value, i.e. to 4 kHz for units with

factory setting 2 kHz and to 2.5 kHz for units with factory setting 1.25 kHz.

· The maximum permissible output frequency is limited to 150 Hz.

· The minimum, continuously permissible output frequency is:

§ 0 Hz with dv/dt filters plus VPL

§ 10 Hz with dv/dt filters compact plus VPL

Operation at output frequencies of < 10 Hz is permissible for 5 minutes maximum if this is followed by

a period of operation at output frequencies of > 10 Hz for 5 minutes minimum.

However, this restriction at low output frequencies applies only if the maximum permissible

pulse frequency and the maximum permissible motor cable length of the dv/dt filter compact plus VPL

are utilized to almost 100 % at the same time.

If only 50 % or less of the maximum permissible pulse frequency or the maximum permissible cable length

is utilized, the restriction related to low output frequencies described above does not apply.

No limits apply with respect to permissible pulse patterns of the gating unit, i.e. pulse-edge modulation can be used

without restriction, which means that the attainable output voltage is virtually equal to the input voltage.

The voltage drop across the dv/dt filter plus VPL or dv/dt filter compact plus VPL equals approximately 1 %.

The dv/dt filters must be selected with parameter setting P0230 = 2 when the drive is commissioned. This ensures

that optimum allowance will be made for the effect of the filter in the vector control model.

dv/dt filters can be used in both grounded systems (TN/TT) and non-grounded systems (IT).

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1.10.3 Sine-wave filters

1.10.3.1 Design and operating principle

Sine-wave filters are LC low-pass filters and constitute the most sophisticated filter solution. They are significantly

more effective than dv/dt filters plus VPL and dv/dt filters compact plus VPL in reducing voltage rates-of-rise dv/dt

and peak voltages VPP, but operation with sine-wave filters imposes substantial restrictions in terms of the possible

pulse frequency settings and utilization of the inverter current and voltage.

As the schematic diagram below illustrates, the sine-wave filter extracts the fundamental component of the inverter

pulse pattern. As a result, the voltage applied to the motor terminals is sinusoidal with an extremely small harmonic

content.

Schematic diagram of the voltage v(t) at the inverter output and motor terminals with a sine-wave filter

Sine-wave filters very effectively limit both voltage rate-of-rise dv/dt and the peak voltage VPP on the motor winding to

the following values:

· Voltage rate-of-rise dv/dt << 50 V/ms

· Peak voltage VPP < 1.1 * √2* VLine

As a result, the voltage stress on the motor winding is virtually identical to the operating conditions of motors directly

connected to the mains supply. Bearing currents are also reduced significantly. Using these filters therefore allows

standard motors with standard insulation and without insulated bearing to be operated on SINAMICS. This applies to

both Siemens motors and motors supplied by other manufacturers.

Due to the very low voltage rate-of-rise on the motor cable, the sine-wave filter also has a positive impact in terms of

electromagnetic compatibility. As a result, in cases where the motor cables are relatively short, it is not absolutely

essential to use shielded motor cables for EMC reasons.

Since the voltage applied to the motor is not pulsed, the converter-related stray losses and additional noise in the

motor are also reduced considerably and the noise level of the motor is approximately equivalent to the level

produced by motors operating directly on the line supply voltage.

Sine-wave filters are available

· in the 380 V to 480 V voltage range up to a converter rated output of 250 kW at 400 V,

· in the 500 V to 600 V voltage range up to a converter rated output of 132 kW at 500 V,

Fundamental Principles and System Description

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The table below specifies the permissible motor cable lengths in systems with sine-wave filter for SINAMICS G130,

G150, S150, S120 Motor Modules (Chassis and Cabinet Modules).

Maximum permissible motor cable length with sine-wave filter

Line supply voltage Shielded cable

e.g. Protodur NYCWY

Unshielded cable

e.g. Protodur NYY

380 V – 480 V 3AC 300 m 450 m

500 V – 600 V 3AC 300 m 450 m

Maximum permissible motor cable lengths with sine-wave filter for SINAMICS G130, G150, S150

and SINAMICS S120 Motor Modules in Chassis and Cabinet Modules format

These cable lengths apply to drives on which only one motor is connected to the filter output. Longer motor cable

lengths may be used for drives with multiple motors at the filter output. Please refer to section "Motor reactors" for

information on how to calculate the permissible motor cable lengths drives with multiple motors. If the calculation

method described in this section is applied for converters with sine-wave filters, it must be noted that the relevant

recommended values nS rec and A rec as stated in the catalog must be used instead of the maximum number of

parallel cables nS max and maximum cross-sections Amax.

1.10.3.2 Supplementary conditions which apply when sine-wave filters are used

It must be noted that the sine-wave filter should be sited in the immediate vicinity of the converter or inverter output in

the case of SINAMICS G130 and S120 Chassis units. The cable length between the sine-wave filter and the output of

the converter or inverter should not exceed about 5 m.

To make allowance for resonant frequency, the pulse frequency setting for systems with sine-wave filters is fixed at

4 kHz (380 V – 480 V) or at 2.5 kHz (500 V – 600 V). For this reason, the permissible output current is reduced to the

values given in the table below.

Line supply voltage Rated output power

at 400 V resp. 500 V

without sine-wave

filter

Rated output current

without sine-wave filter

Current derating factor

with sine-wave filter

Output current

with sine-wave filter

380 V – 480 V 3AC 110 kW 210 A 82 % 172 A

380 V – 480 V 3AC 132 kW 260 A 83 % 216 A

380 V – 480 V 3AC 160 kW 310 A 88 % 273 A

380 V – 480 V 3AC 200 KW 380 A 87 % 331 A

380 V – 480 V 3AC 250 kW 490 A 78 % 382 A

500 V – 600 V 3AC 110 kW 175 A 87 % 152 A

500 V – 600 V 3AC 132 kW 215 A 87 % 187 A

Current derating factor and permissible output current with sine-wave filter

When sine-wave filters are used, it is absolutely essential to operate the drive in space vector modulation mode

(p1802=3 / SVM without overmodulation), i.e. these filters are not compatible with pulse-edge modulation.

As a consequence, the motor voltage that can be attained with G130, G150 and S120 Motor Modules that are

supplied by Basic Infeeds or Smart Infeeds is limited to app. 85 % of the input voltage in the case of 380 V – 480 V,

or to app. 83 % in the case of 500 V – 600 V. The drive therefore reaches the field weakening range earlier. Since the

motor cannot reach its rated voltage, it can only achieve its rated output if it is operated on a current that is higher

than the rated current.

With S150 and S120 Motor Modules that are supplied by Active Infeeds, the DC link voltage is in the factory setting

approximately 13 % higher than with the Basic Infeed or Smart Infeed due to the fact that the Active Infeed operates

in step-up converter mode. As a consequence, the motor voltage reaches app. 95 % of the line supply voltage in

space vector modulation mode (p1802=3 / SVM without overmodulation). By increasing the parameterizable DC link

voltage (parameter p3510 / Infeed DC link voltage setpoint) by around 5 % as compared to the factory setting, it is

possible, however, to reach with the Active Infeed the full line supply voltage at the motor when using space vector

modulation mode without overmodulation.

In operation with sine-wave filters, the maximum output frequency is limited to 150 Hz (380 V – 480 V) or 115 Hz

(500 V – 600 V).

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It is essential to select sine-wave filters via parameter p0230 during drive commissioning.

If sine-wave filters from the SINAMICS product range are used, p0230 must be set to "3". This will ensure that all of

the necessary parameter changes in connection with the sine-wave filters are implemented automatically and

correctly.

If sine-wave filters supplied by manufacturers other than Siemens are used, p0230 must be set to "4". This setting

effects an overload reaction without pulse frequency reduction (p0290=0 or 1) and sets the modulator mode to space

vector modulation without overmodulation (p1802=3). The technical data of the sine-wave filter must also be entered

in other parameters, i.e. p0233 and p0234, and the maximum frequency and/or maximum speed (p1082) as well as

the pulse frequency (p1800) must be parameterized in accordance with the data sheet for the sine-wave filter. For

further information, please refer to the List Manuals or Parameter Descriptions.

Sine-wave filters can be used in both, grounded systems (TN/TT) and non-grounded systems (IT).

Sine-wave filters are compatible only with vector and V/f control modes, but not with servo control mode.

Information about sine-wave filters supplied by third-party manufacturers:

In order to ensure a stable control performance in operation, the resonance frequency of the third-party filter must be

in a specific relation with the current controller clock cycle TI and the pulse frequency fPulse of the SINAMICS

converter or inverter. The following formulas (all of which need to be satisfied) describe the relevant dependencies.

Possible resonance frequencies fRes of the third-party filter as a function of the set current controller clock cycle TI:

fRes = n1 • [1 / (2 • TI)] where n1 = 1, 3 (applies to vector and V/f control modes) (1)

Possible pulse frequencies fPulse of the SINAMICS converter as a function of the set current controller clock cycle TI:

fPulse = n2 • [1 / TI ] where n2 = ½, 1, 2, 3, . (applies to vector and V/f control modes) (2)

Possible resonance frequencies fRes of the third-party filter as a function of the pulse frequency fPulse:

fRes ≤ fPulse / 2. (applies to vector and V/f control modes) (3)

The table below shows the mathematically possible resonance frequencies of the third-party filter, the mathematically

possible pulse frequencies of the SINAMICS converter and the permissible combinations of resonance frequency and

pulse frequency calculated according to the equations above for the most commonly used current controller clock

cycles TI = 250 µs, 400 µs and 500 µs.

Current

controller

clock cycle

TI / µs

Mathematically possible

resonance frequencies

acc. to equation (1)

fRes / kHz

Mathematically possible

pulse frequencies

acc. to equation (2)

fPulse / kHz

Permissible combinations of

resonance frequency and

pulse frequency

acc. to equations (1) - (3)

fRes / kHz and fPulse / kHz

250 2 / 6 2 / 4 / 8 … 2 and 4

2 and 8

400 1.25 / 3.75 1.25 / 2.5 / 5 / 7.5 …

1.25 and 2.5

1.25 and 5.0

1.25 and 7.5

3.75 and 7.5

500 1 / 3 1 / 2 / 4 / 6…

1.0 and 2.0

1.0 and 4.0

1.0 and 6.0

3.0 and 6.0

Resonance frequencies of the third-party filter and converter pulse frequencies that are mathematically possible, as well

as possible combinations of resonance frequency and pulse frequency for the most commonly used current controller

clock cycles 250 µs, 400 µs and 500 µs

Notice:

Failure to observe the dependencies specified in the equations and/or the table can result in unstable control

behavior of the converter/third-party filter system – especially in vector control mode. In the worst-case scenario, this

can cause the drive to oscillate as soon as it is started up in V/f control or vector control mode with the result that it

trips immediately on the fault "overcurrent".

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1.10.4 Comparison of the properties of the motor-side reactors and filters

The table below provides an overview of the key properties of the motor-side reactors and filters.

Converter output: Without

reactor or filter

With

motor reactor

With

dv/dt filter

With

sine-wave filter

Voltage rate-or-rise dv/dt

at the motor terminals

High

(see chart

on next page)

Medium

(see chart

on next page)

Low

(see chart

on next page)

Very low

(see chart

on next page)

Peak voltage VPP

at the motor terminals

High

(see chart

on next page)

Relatively high

(see chart

on next page)

Low

(see chart

on next page)

Very low

(see chart

on next page)

Permitted

pulse modulation systems No restrictions No restrictions No restrictions Space vector

modulation SVM only

Permitted

pulse frequencies No restrictions ≤ 2x factory setting ≤ 2x factory setting Exactly 2x factory

setting

Permitted

output frequencies No restrictions ≤ 150 Hz ≤ 150 Hz ≤ 150 Hz

Permitted

control modes

Servo control

Vector control

V/f control

Servo control

Vector control

V/f control

Servo control

Vector control

V/f control

Vector control

V/f control

Control quality and

dynamic response Very high High High Low

Stray losses

in reactor or filter

relative to converter

losses in rated operation

–Approx. 10 % Approx. 10 – 15 % Approx. 10 – 15 %

Stray losses in motor

due to converter supply

relative to rated operation Approx. 10 % Approx. 10 % Approx. 10 % Very low

Reduction in motor noise

caused by converter

No Minimal Minimal Significant

Reduction in bearing currents

in the motor

No Medium Yes Yes

Max. cable length shielded

Max. cable length unshielded

300 m

450 m

300 m

450 m

100 m or 300 m

150 m or 450 m

300 m

450 m

Volume –Low Medium Medium

Price –Low Medium to high High

Comparison of the key propertiesof motor-side reactors and filters

Fundamental Principles and System Description

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The charts below show the typical voltage rates-of-rise dv/dt and peak voltages VPP at the motor terminals, both with

and without motor-side reactors and filters, as a function of the motor cable length. The specified peak voltages VPP

are referred in each case to the rms value of the line supply voltage VLine.

The values apply to converters with line-commutated Infeeds (G130 and G150 converters, and drives with S120

Basic Line Modules and S120 Smart Line Modules) and with shielded motor cables with the recommended cable

cross-sections according to the sections on specific unit types in this engineering manual. Furthermore, the values

apply to steady-state operation. With braking operations of brief duration during which either the Vdc max controller or

a braking unit (Braking Module) is active, the values increase in proportion to the increased DC link voltage.

The values are typically about 10 % higher for converters with self-commutated Infeeds (S150 converters and drives

with S120 Active Infeeds) due to the increased DC link voltage.

Typical voltage rates-of-rise at the motor terminals

for SINAMICS drives with line-commutated Infeeds

as a function of the motor cable length

Typical peak voltages VPP / VLine at the motor terminals

for SINAMICS drives with line-commutated Infeeds

as a function of the motor cable length

The charts clearly show that dv/dt filters plus VPL, dv/dt filters compact plus VPL as well as sine-wave filters are very

effective at reducing the voltage rates-of-rise and the peak voltages on the motor. Both types of filter are therefore

equally suited for the purpose of successfully operating older motors with unknown winding insulation, or motors

without special winding insulation for converter-fed operation, on SINAMICS converters up to line voltages of 690 V.

More detailed explanations about voltage rates-of-rise dv/dt and peak voltages VPP at the motor terminals without

motor-side reactors and filters (physical causes and influencing parameters) can be found in section "Increased

voltage stress on the motor winding as a result of long motor cables".

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1.11 – – –

1.12 Power cycling capability of IGBT modules and inverter power units

1.12.1 General

The term "Power cycling capability" refers to the capability of a component, for example, a fuse or an IGBT module,

to withstand temperature fluctuations caused by an alternating current load during operation without suffering

premature wear or failure.

To ensure that the IGBT modules used in the SINAMICS power units are always operated within a range of a

sufficient power cycling capability, the following aspects must be considered at the drive configuring stage. A

sufficient power cycling capability necessitates either the prevention of critical operating conditions or proper over-

dimensioning of the units themselves.

The following sections explain the physical background and give dimensioning guidelines for selecting IGBT modules

and thus power units to ensure a sufficient power cycling capability for the application in question.

1.12.2 IGBT module with cyclically alternating current load

The diagram below shows the internal design of an IGBT module plus the temperature characteristics of the IGBT

chip, the base plate and the heatsink when the chip is subject to a cyclically alternating current load.

Design of an IGBT module and temperature characteristics with a cyclically alternating current load

Owing to the mechanical design of the IGBT module which comprises several layers of different materials, there is a

relatively high thermal resistance between the IGBT chip in which the heat losses occur, and the base plate of the

IGBT via which the heat losses are discharged to the power unit heat sink. As a result, there are very significant

fluctuations in the temperature of the IGBT chip when it is subjected to a cyclically alternating current load, while the

temperatures of the base plate and heat sink remain relatively constant.

Under critical operating conditions, temperature cycles with such a high temperature swing ΔTChip can occur that the

IGBT module is subjected to substantial thermal stressing, resulting in a significant reduction in the IGBT lifetime.

This is because the number of permissible temperature cycles of an IGBT is limited and is further reduced as the

temperature swing ΔTChip increases. As a consequence, the lifetime of the IGBT is also reduced in proportion to the

increase in temperature swing ΔTChip.

Critical operating conditions with severe cyclic fluctuations in the IGBT chip temperature include the following

scenarios:

·Periodic load duty cycles with pronounced load current fluctuations combined with short duty cycle times

·Operation at low output frequencies combined with high output current

Cyclically alternating current load

Heatsink

Base plate

Heatsink

Bond

wire

Base plate

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In the case of periodic load duty cycles with pronounced load current fluctuations (high short-time current and low

base load current), the temperature of the IGBT chips rises quickly during the overload period. The IGBT chips cool

down again very quickly during the subsequent period of base load current. As a consequence, the temperature

swings ΔTChip are very pronounced, resulting in a small number of permissible temperature cycles. The permissible

number of temperature cycles can thus be reached relatively quickly in combination with short load cycle times, in

turn resulting in a relatively short IGBT lifetime. In order to prevent premature failure of the IGBTs due to periodic load

duty cycles which involve pronounced load current fluctuations, the appropriate current derating factor kIGBT defined in

section "Free load duty cycles" must be taken into account when load duty cycles are configured.

In operation with a low output frequency and a high output current, the output current flows during the positive half-

wave only through the IGBT connected to the positive bus of the DC link for a very long period as a result of the low

output frequency. As a result, the chips in this IGBT reach a very high temperature when the output current is high

while the temperature of the chips in the IGBT connected to the negative bus of the DC link drops quickly. During the

negative half-wave of the output current, the conditions are reversed. Under these operating conditions – even when

the rms value of the output current remains constant – the current load on the IGBT chips alternates with the output

frequency, resulting in very high absolute chip temperatures TChip and extremely high temperature swings ΔTChip. In

order to prevent instantaneous fault tripping as well as premature failure of the IGBTs in operation with a low output

frequency and high output current, the configuring guidelines outlined below must be observed.

Two criteria need to be satisfied to ensure correct operation of an IGBT module at low output frequencies, i.e. in

order to prevent immediate shutdown as a result of excessive chip temperature TChip and to avoid premature failure

of the IGBT module as a result of excessive temperature swing ΔTChip:

· The absolute chip temperature TChip of the IGBT must never exceed the permissible limit value. This condition

must always be satisfied at every operating condition to protect the IGBT chip against instantaneous fatal

damage. The damage caused by excessive chip temperature is reliably prevented by the thermal monitoring

model implemented in SINAMICS converters which triggers an overload reaction when the permissible

temperature limit is reached. However, measures must be taken at the configuring stage to ensure that this

protective mechanism does not respond under the normal operating conditions for which the drive is

dimensioned.

· The temperature swing ΔTChip of the IGBT must not exceed the permissible limit value at all, or only for a tiny

fraction of the total operating time. This condition must be fulfilled to avoid any significant reduction in the

lifetime of the IGBT. The temperature fluctuation is not continuously monitored by the thermal model.

Measures must therefore be taken at the configuring stage to ensure that the IGBT does not exceed the

permitted temperature fluctuation at all, or only for a small fraction of less than approximately 1 % to max. 2 %

of the total operating time. Brief violations of the permissible limit, e.g. during rare starting or braking

operations, are therefore no problem provided that these operating conditions occur only for a small fraction of

less than about 1 % to max. 2 % of the total operating time.

1.12.3 Dimensioning of the power units for operation at low output frequencies

At high output frequencies, the chip temperature TChip and the chip temperature swing ΔTChip always remain within

permissible limits in both steady-state continuous operation and in all permissible load duty cycles specified in section

"Load duty cycles". As the output frequency decreases, the chip temperature and chip temperature fluctuation

increase continuously and can reach critical values below 10 Hz.

If no allowance is made for this relation when the drive is configured, there is a risk, depending on the operating

conditions, that the thermal monitoring model will intervene in an undesirable way and / or that the lifetime of the

IGBTs will be significantly reduced.

Measures which can be taken to prevent these problems are explained below.

1.12.3.1 Operation without overload at low output frequencies < 10 Hz

Depending on whether it is only necessary to prevent intervention by the thermal monitoring model in the event of

occasional low output frequencies, or whether the lifetime of the IGBTs also needs to be considered in cases where

low output frequencies occur frequently, i.e. corresponding to more than approximately 1 % to max. 2 % of the total

period of operation, the measures to be taken differ.

1.12.3.1.1 Operation without overload with occasional periods of low output frequencies < 10 Hz

In this case, the drive must only be configured to ensure that no overload reaction is initiated by the thermal

monitoring model. The effect on the lifetime of the IGBTs is negligible and need not be taken into account.

If the converter is to be operated occasionally, i.e. for a period corresponding to less than approximately 1 % to max.

2 % of its total operating period, at output frequencies of less than 10 Hz without intervention by the overload

reaction, the output current must be derated as a function of the output frequency according to the derating curve

below (precondition: Overload reaction setting is p290 = 1).

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Permissible output current

Permissible output current in operation without overload with occasional

periods of low output frequencies as a function of the output frequency

1.12.3.1.2 Operation without overload with frequent periods of low output frequencies < 10 Hz

In this case, the converter must be configured to ensure that the thermal monitoring model does not trigger

inappropriate overload reactions and that the lifetime of the IGBTs is not significantly reduced.

If the converter is to be operated frequently, i.e. for a period corresponding to more than approximately 1 % to max.

2 % of its total operating period, or continuously at output frequencies of less than 10 Hz without intervention of an

overload reaction and without risk of premature IGBT failure, the output current must be reduced as a function of the

output frequency according to the derating curve below.

Permissible output current

Output frequency

100

10 15 Hz

Permissible output current in operation without overload with frequent

periods of low output frequencies as a function of the output frequency

1.12.3.2 Operation with high overload at low output frequencies < 10 Hz

As the output frequency decreases, the absolute chip temperature TChip reaches its limit value after ever shorter

periods of overload with the result that the thermal monitoring model might eventually intervene after very short

periods of overload. This must be taken into account at the configuring stage.

As the output frequency decreases, the temperature swing ΔTChip also increases continuously during the overload

period. If the periods of overload occur frequently or periodically with more than approximately 1 % to max. 2 % of the

total operating period, measures must be taken to ensure that the lifetime of the IGBTs is not reduced.

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Depending on whether it is only necessary to prevent the intervention by the thermal monitoring model at occasional

overloads or whether the lifetime of the IGBTs has to be taken in account when the sum of the overload periods

corresponds to more than about 2 % of the total operating time, different measures are required.

1.12.3.2.1 Operation with high overload with occasional periods of low output frequencies < 10 Hz

In this case, the drive must only be configured to ensure that no overload reaction is initiated by the thermal

monitoring model. The effect on the lifetime of the IGBTs is negligible and need not be taken into account.

If the converter occasionally has to operate without triggering an overload reaction for a period corresponding to less

than approx. 1 % to max. 2 % of its total operating time at output frequencies of less than 10 Hz with a short-time

current of IShortTime = 1.5 • IH according to the load duty cycle "high overload", then the short-time current IShortTime and

the associated base load current IH must be reduced depending on the output frequency and the overload period t in

accordance with the following derating characteristic (precondition: Overload reaction parameter is set to p290 = 1).

Permissible short-time current and permissible base load current with occasional

high overload as a function of the output frequency and the overload period t

Note:

As the derating curve indicates, high current loads for brief periods at low output frequencies, such as those which

might occur during occasional starting and braking, can be ignored if they do not last longer than around 0.5 s in each

case and the high current load period corresponds to less than 1 % to max. 2 % of the total operating time.

As an example, the hoisting drive for a container crane is normally accelerated or braked at high current several

times within a period of 1 minute. However, since the operating conditions - which involve low output frequencies and

high output currents - normally last only for a period of fractions of a second and do not typically total more than

approximately 1 % to max. 2 % of the total operating time of the hoisting drive, no derating needs to be applied when

drives of this type are configured.

1.12.3.2.2 Operation with high overload with frequent periods of low output frequencies < 10 Hz

In this case, the converter must be configured to ensure that the thermal monitoring model does not trigger

inappropriate overload reactions and that the lifetime of the IGBTs is not significantly reduced.

If the converter frequently has to operate without triggering an overload reaction and without risk of premature IGBT

failure for a period corresponding to more than approximately 1 % to max. 2 % of its total operating time or

permanently at output frequencies of less than 10 Hz with a short-time current of IShortTime = 1,5 • IH according to the

load duty cycle "high overload", then the short-time currrent IShortTime and the associated base load current IH must

be reduced depending on the output frequency in accordance eith the following derating characteristic.

Fundamental Principles and System Description

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Permissible short-time current and permissible base load current with frequent

periods of high overload as a function of the output frequency

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1.13 Load duty cycles

1.13.1 General

In many applications, especially constant-torque applications, variable-speed drives are required to operate under

overload conditions.

Overload capacity may be required occasionally, for example, in order to

· overcome breakaway torques on starting,

· produce acceleration torques for short periods, or

· decelerate drives rapidly in emergency situations.

However, overload capacity may also be needed periodically, for example, within recurrent load duty cycles for

· shears,

· flywheel presses and servo presses,

· centrifuges,

· test bays in the automotive industry,

· amusement rides in theme parks.

For the converters and inverters to be able to produce the required overload capacity, they must not be operated to

the limit of their thermal capacity prior to and following the overload periods. For this reason, the base load current for

drives which require overload capacity must be lower than the continuously permissible thermal rated current. The

more the base load current is reduced from rated current value, the higher will be the thermal reserves for periods of

overload duty.

1.13.2 Standard load duty cycles

For SINAMICS G130 converter Chassis, SINAMICS G150 and S150 converter cabinets and SINAMICS S120 Motor

Modules SINAMICS S120 (Chassis and Cabinet Modules), the overload capability is defined by two standard load

duty cycles:

· Load duty cycle for low overload (LO) with a base load current ILthat is marginally lower (3 % to 6 %)

than the rated output current Irated.

· Load duty cycle for high overload (HO) with a base load current IHthat is significantly lower (10 % to

25 %) than the rated output current Irated.

The diagrams below show the load duty cycle definitions for operation under low and high overloads.

· The base load current ILfor low overload is based on a load duty cycle of 110 % for 60 s or 150 % for

10 s.

· The base load current IHfor high overload is based on a load duty cycle of 150 % for 60 s or 160 % for

10 s.

The maximum possible short-term current of the load duty cycle low overload (LO) is 1.5 * ILfor 10 s. This value is

always slightly higher than the maximum possible short-term current of the load duty cycle high overload (HO), which

is 1.6 *IHfor 10 s. Thus the maximum possible output current Imax of the power unit is defined by Imax = 1.5 * IL.This

maximum value is set in the firmware and can, therefore, not be exceeded, not even in short-term operation.

The values for the base load currents IL and IH, as well as for the maximum output current Imax, are unit-specific and

must therefore be taken from the relevant catalogs or the chapters on specific unit types in this engineering manual.

These short-time currents apply on the condition that the converter is operated at its base load current before and

after the period of overload on the basis of a load duty cycle duration of 300 s in each case. Another precondition is

that the converter is operated at its factory-set pulse frequency at output frequencies higher than 10 Hz.

Where the ratio ΔI between short-time current and base load current or the load duty cycle duration T or the pulse

frequencies fPulse are different, the overload capacity must be calculated in accordance with section "Free load duty

cycles" below.

At output frequencies below 10 Hz, the additional restrictions described in section "Power cycling capability of IGBT

modules and inverter power units" apply.

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Definition of the standard load duty cycle low overload Definition of the standard load duty cycle high overload

1.13.3 Free load duty cycles

Many applications require load duty cycles which deviate to a greater or less extent from the standard load duty

cycles defined above. The section below therefore explains the physical correlations and design criteria which must

be taken into account.

Load duty cycles must fullfill the following criteria in order to prevent overloading of the power unit and thus avoid

immediate fault tripping, initiation of an overload reaction or reduction in the life of the converter:

· The magnitude of the short-time current must generally be limited to permissible values in order to prevent

initiation of an overload reaction.

· In the case of periodically recurring load duty cycles, the frequency and/or magnitude of variations in the

IGBT chip temperature must be limited to permissible values during the load duty cycle to prevent premature

failure of power units.

· The average power losses in the power unit must generally be limited during the duty cycle to the value

permissible for steady-state continuous operation in order to prevent initiation of an overload reaction.

The magnitude of the short-time current must generally be limited for a number of reasons: The first reason is that a

sufficient margin must be maintained between the current during the overload period and the overcurrent tripping

threshold of the power unit in order to prevent the unit from shutting down immediately on overcurrent. The second

reason is that the chip temperature in the IGBT rises during the overload period. Since this rise is proportional to the

square of the short-time current, there is a disproportionate reduction in the permissible overload period as the short-

time current rises. As a result, a very high short-time current will very quickly result in initiation of an overload reaction

or tripping of the unit due to chip thermal overloading.

In the case of periodic load duty cycles, the magnitude and/or frequency of variations in the IGBT chip temperature

must be limited during the load duty cycle in order to prevent premature failure of power units. This is necessary

because the number of permissible temperature cycles of an IGBT is limited and is further reduced as the

temperature swing ΔTChip increases. The lifetime of the IGBT therefore also decreases accordingly in proportion to

the rise of the temperature swing ΔTChip, as described in section "Power cycling capability of IGBT modules and

inverter power units". The following therefore applies to periodically recurrent load duty cycles:

If the ratio ΔI between short-time current and base load current is small in periodic load duty cycles, and the resultant

temperature swings ΔTChip are correspondingly low, the magnitude of the short-time current needs not be limited or

only slightly limited in addition to the criteria stated above for the purpose of preserving lifetime as the duration of the

duty cycle decreases.

If the ratio ΔI between short-time current and base load current is large in periodic load duty cycles, and the resultant

temperature swings ΔTChip are correspondingly high, the magnitude of the short-time current must be limited in

addition to the criteria stated above for the purpose of preserving lifetime as the duration of the duty cycle decreases.

The average power losses in the power unit during the load duty cycle must be limited generally and must not exceed

the corresponding power loss in steady-state continuous operation at the permissible output current for which the

power unit is thermally rated. This is necessary in order to prevent initiation of an overload reaction or tripping of the

unit due to excessive chip temperature.

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If the criteria described above are applied to the SINAMICS G130, G150 and S150 converters and to the SINAMICS

S120 inverter Motor Modules (Chassis and Cabinet Modules), then free load duty cycles are permissible whenever

the following conditions are fulfilled:

The short-time current IShortTime must be limited to values less than 1.5 * kD* IH.

(In the case of parallel connections of S120 Motor Modules, IShortTime is the short-time current of one inverter section

or one Motor Module)

The current derating factor kD takes into account all influences which necessitate a reduction in the short-time current

of the converter or inverter:

IGBTParallelPulseTempD kkkkk ×××= .

Key to equation:

· k

DCurrent derating factor (total derating factor),

· k

Temp Derating factor for increased ambient temperature in the 40 °C to 50 °C / 55 °C range,

· k

Pulse Derating factor for pulse frequencies higher than the factory-set pulse frequency,

· k

Parallel Derating factor for parallel operation of S120 Motor Modules,

· k

IGBT Derating factor for periodic load duty cycles in order to protect against premature IGBT failure.

The derating factors kTemp and kPulse are unit-specific and can be found in the appropriate catalogs or the unit-specific

sections of this engineering manual. With respect to the derating factor kPulse, the information in section "Operation of

converters at increased pulse frequency" must be observed.

The derating factor kParallel is generally 0.95 for SINAMICS S120 Motor Modules.

The derating factor kIGBT is unit-specific and must only be applied in the case of regularly recurring, periodic load duty

cycles (e.g. shears, presses, centrifuges, amusement rides in theme parks, etc.) in order to limit the temperature

swing ΔTChip in the IGBT and thus to protect against premature IGBT failure.

The following derating characteristics specify the

derating factor kIGBT as a function of the current ratio

ΔI = IShortTime / IBaseLoad and the load duty cycle duration

The assignment between derating characteristics 1 to 3

and SINAMICS G130 and G150 converters, SINAMICS

S120 Motor Modules (air-cooled and liquid-cooled) and

SINAMICS S150 converters are given in the assignment

table on the following page.

Derating factor kIGBT as a function of the current ratio ΔI = IShort Time / IBase Load and the load duty cycle duration T

Fundamental Principles and System Description

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SINAMICS G130

Converter chassis units

SINAMICS G150

Converter cabinet units

SINAMICS S120

Motor Modules air-cooled

(Chassis + Cabinet Modules)

SINAMICS S150

Converter cabinet units

SINAMICS S120

Motor Modules liquid-cooled

(Chassis)

Output

power

400V/

500V/

690V

[kW]

Rated

output

current

[A]

De-

rating

charac-

teristic

Output

power

400V/

500V/

690V

[kW]

Rated

output

current

[A]

De-

rating

charac-

teristic

Output

power

400V

690V

[kW]

Rated

output

current

[A]

De-

rating

charac-

teristic

Output

power

400V

690V

[kW]

Rated

output

current

[A]

De-

rating

charac-

teristic

380V – 480 3AC 380V – 480V 3AC or 510V – 720V DC

110 210 3 110 210 3 110 210 3 110 210 3

132 260 2 132 260 2 132 260 2 132 260 2

160 310 1 160 310 1 160 310 1 160 310 1

200 380 2 200 380 2 200 380 2 - - -

250 490 3 250 490 3 250 490 3 250 490 3

315 605 3 315 605 3 315 605 3 315 605 3

400 745 3 400 745 3 400 745 3 400 745 3

450 840 3 450 840 3 450 840 3 450 840 3

560 985 2 560 985 2 560 985 2 560 985 2

- - - 630 1120 3 710 1260 1 710 1260 1

- - - 710 1380 3 800 1330 1 800 1330 k

IGBT

= 1

- - - 900 1560 3 800 1405 2 800 1405 2

500V – 600V 3AC

110 175 1 110 175 1

132 215 1 132 215 1

160 260 1 160 260 1

200 330 2 200 330 2

250 410 1 250 410 1

315 465 1 315 465 1

400 575 1 400 575 1

500 735 1 500 735 1

560 810 2 560 810 2

- - - 630 860 1

- - - 710 1070 1

- - - 1000 1360 1

660V – 690V 3AC 500V – 690V 3AC or 675V – 1035V DC

75 85 1 75 85 1 75 85 1 - - -

90 100 1 90 100 1 90 100 1 90 100 1

110 120 1 110 120 1 110 120 1 - - -

132 150 2 132 150 2 132 150 2 132 150 2

160 175 1 160 175 1 160 175 1 - - -

200 215 1 200 215 1 200 215 1 200 215 1

250 260 1 250 260 1 250 260 1 - - -

315 330 2 315 330 2 315 330 2 315 330 2

400 410 1 400 410 1 400 410 1 - - -

450 465 1 450 465 1 450 465 1 450 465 1

560 575 1 560 575 1 560 575 1 560 575 1

710 735 1 710 735 1 710 735 1 710 735 2

800 810 2 800 810 2 800 810 1 800

810 2

- - - 1000 1070 1 900 910 1 800

810 1

- - - 1350 1360 1 1000 1025 1 1000 1025 1

- - - 1500 1500 2 1200 1270 2 1200 1270 2

- - - 1750 1729 1 - - - 1500 1560 1

- - - 1950 1948 1 - - - - - -

- - - 2150 2158 2 - - - - - -

- - - 2400 2413 2 - - - - - -

- - - 2700 2752 1 - - - - - -

1) Article number 6SL3325-1TG38-0AA3 (frame size HXL) 2) Article number 6SL3325-1TG38-1AA3 (frame size JXL)

Assignment table between derating characteristics 1 to 3 and SINAMICS G130 and G150 converters, SINAMICS S120 Motor

Modules (air-cooled and liquid-cooled) and SINAMICS S150 converters

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The I2t value, averaged over a load duty cycle duration T of max. 300 s, must not exceed the 100 % value. The

exeptions are stated in the table.

For the following SINAMICS converters or Motor Modules the permissible I2t value is limited to values of less than

100 % with load duty cycles:

Converter

Motor Module

Line

volt-

age

Output

rat-

ing

Output

current

Permissible

I2t value

with load

duty cycles

Converter

Motor Module

Line

volt-

age

Output

rat-

ing

Output

current

Permissible

I2t value

with load

duty cycles

SINAMICS G and S 400 V 110 kW 210 A 90 % SINAMICS G 400 V 630 kW 1120 A 72 %

SINAMICS G and S 400 V 315 kW 605 A 72 % SINAMICS G 400 V 710 kW 1380 A 73 %

SINAMICS G and S 400 V 400 kW 745 A 73 % SINAMICS G 400 V 900 kW 1560 A 86 %

SINAMICS G and S 400 V 450 kW 840 A 87 % SINAMICS G + S 500 V 200 kW 330 A 90 %

SINAMICS G and S 400 V 560 kW 985 A 95 % SINAMICS G + S 690 V 315 kW 330 A 90 %

SINAMICS S 4AS3 400 V 800 kW 1330 A 93 %

The I2t value is the criterion for losses and temperature rise in the power unit during the load duty cycle and is defined

as follows:

valuetI

DRated

2)(1 ò÷

×= • 100 %

Key to equation:

· I(t) RMS value of the output current of the converter or inverter as a function of time

(In the case of parallel connections of S120 Motor Modules, I(t) is the RMS value of the output

current of a partial inverter resp. one Motor Module.)

· I

Rated Rated output current of the converter or inverter

(In the case of parallel connections of S120 Motor Modules, IRated is the rated output current of a

partial inverter resp. one Motor Module, not taking into account the derating factor for parallel

operation.)

· k

DCurrent derating factor (total derating factor; see above for definition)

· T Load duty cycle duration which must not exceed the 300 s value for the standard load duty cycle

For the practical calculation of the I2t value, it is generally helpful to apply a finite number m of phases of constant

current in each case as an approximate substitute to the output current time characteristic required by the application.

This simplifies the calculation as the integration is replaced by a simple summation.

é×

++×

+×

×= m

DRated

DRatedDRated

valuetI

2......

1• 100 %

where TT

i.e. the sum of all phases T1 to Tm

equals the load duty cycle duration T, where T must be ≤ 300 s. The diagram

below illustrates the correlations.

Approximation of the current characteristic over time using time phases with constant current

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Commissioning information

In order to minimize to the greatest possible extent the inevitable temperature fluctuations which occur as a result of

load changes within a load duty cycle, drives with periodically recurrent load duty cycles and load duty cycle

durations ranging from several seconds to several minutes should not only be configured in accordance with the rules

described above, but the following points should also be taken into consideration. This applies in particular if the

current derating factor kIGBT calculated for the drive configuration is < 1.0.

The drive must either be commissioned with the configured pulse frequency or with meaningfully selected,current-

dependent switchover between different pulse frequencies.

If the drive is commissioned with a constant pulse frequency which is the same as the configured pulse frequency,

the power unit will be guaranteed to have an acceptably long lifetime.

An additional reduction in the temperature swings ΔTChip can be achieved through current-dependent switchover

between different pulse frequencies. This is because the temperature rise can be minimized by operating the

converter at a very low pulse frequency in operating states with very high current. In operating states with very low

current, the drop in temperature can be minimized by operating the converter at a very high pulse frequency. By

using switchover between different pulse frequencies as a function of current, it is possible to reduce temperature

fluctuations and thus prolong the lifetime of the IGBTs.

Figure 1 illustrates the interrelationships using the example of a periodically recurrent load duty cycle with a load duty

cycle duration of 2 minutes and load current fluctuations ranging in magnitude between Imin and Imax.

Figure 1: Switchover between pulse frequencies as a function of current

In operation at the configured pulse frequency of 1.25 kHz = constant, the temperature characteristic over time

TChip1(t) is shown by the black curve. The associated temperature swing ΔTChip1 remains within acceptable limits for

the purpose of preserving IGBT lifetime provided that the configuring rules described on the previous pages are

observed.

The implementation of current-dependent switchover between pulse frequencies 1.25 kHz and 2.5 kHz produces the

temperature characteristic over time TChip2(t) as shown by the green curve. Through selection of the low pulse

frequency of 1.25 kHz during periods of load with Imax and the high pulse frequency of 2.5 kHz during periods of load

with Imin, the temperature swing ΔTChip2 is lower than the temperature swing ΔTChip1, so that the corresponding effect

on the lifetime of the IGBTs in the power unit is positive. The difference in the temperature swing can amount to as

much as 5°C in practice, an effect which can increase the IGBT lifetime by a factor of 2 to 3.

Current-dependent switchover between different pulse frequencies can be implemented, for example, using a

combination of free function blocks and switchover between different drive data sets. For this purpose, the converter

or inverter output current is evaluated by a free function block known as the limiter block (LIM). If the current exceeds

a value corresponding to 1.2 times Imin, the output r20232 is set to high. This signal initiates a switchover from a drive

data set with a high pulse frequency (in the example: 2.5 kHz) to a drive data set with a low pulse frequency (in the

example: factory setting 1.25 kHz). If the current drops below a value corresponding to 1.2 times Imin again, the drive

data set with a high pulse frequency (in the example: 2.5 kHz) is activated again.

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Limiter block (LIM) of free function blocks for controlling current-dependent switchover between pulse frequencies

The configured pulse frequency must never be generally increased independently of the different load conditions

using an overload reaction with pulse frequency reduction (p290 = 2 or 3), as described in section "Operation of

converters at increased pulse frequency", in order, for example, to reduce motor noise in applications involving

periodically recurrent load duty cycles with a load duty cycle duration ranging from several seconds to several

minutes. Because, when combined with a pulse frequency higher than the configured pulse frequency, high currents

initiate an overload reaction relatively quickly owing to the high power losses and thus the pulse frequency is reduced

again. However, the overload reaction is not triggered until the IGBT chip temperature TChip reaches a very high level

in order to allow operation of the power unit at a high pulse frequency for as long as possible. This operating mode

with temperature-dependent pulse-frequency switchover as a function of the overload reaction with pulse frequency

reduction thus maximizes the temperature swings in the IGBTs and is therefore not suitable for minimizing

temperature fluctuations in applications with periodically recurrent load duty cycles with short load duty cycle duration

and substantial load fluctuations (current derating factor kIGBT < 1.0).

Figure 2 illustrates the interrelationships using the example of a periodically recurrent load duty cycle with a load duty

cycle duration of 2 minutes and load current fluctuations ranging in magnitude between Imin and Imax.

I(t)

t / s

018060 120 240 300

TChip3(t)

TChip1(t) with fPulse = 1,25 kHz = constant

TChip1(t)

fPulse(t)

1,25 kHz

2,50 kHz

0 kHz

5,00 kHz

TChip3(t) with fPulse = 2,5 kHz or 1,25 kHz

(temperature-depending variation of f Pulse)

Imin Imin Imin

Imax Imax

2,50 kHz 2,50 kHz 2,50 kHz

1,25 kHz 1,25 kHz

ΔTChip3ΔTChip1 <

Figure 2: Switchover between pulse frequencies as a function of temperature

In operation at the configured pulse frequency of 1.25 kHz = constant, the temperature characteristic over time

TChip1(t) is shown by the black curve. The associated temperature swing ΔTChip1 remains within acceptable limits for

the purpose of preserving IGBT lifetime provided that the configuring rules described on the previous pages are

observed.

In operation at a pulse frequency increased to 2.5 kHz, the temperature characteristic over time TChip3(t) is shown by

the red curve. The inverter attempts to continue operation at the higher pulse frequency for as long as possible.

During the periods of load with Imax, the chip temperature TChip3(t) reaches such a high level that an overload reaction

is triggered and the pulse frequency is reduced to 1.25 kHz. Operation continues at this low pulse frequency until the

chip temperature TChip3(t) during a period of load with Imin has decreased far enough again that the pulse frequency

can be changed to 2.5 kHz again.

As a consequence of this temperature-dependent pulse frequency switchover as a function of the overload reaction

with pulse frequency reduction, the temperature swing ΔTChip3 is significantly higher than the temperature swing

ΔTChip1 at a constant, low pulse frequency, with a correspondingly negative impact on the lifetime of the IGBTs in the

power unit. The difference in the temperature swing can amount to as much as 5°C in practice, an effect which can

shorten the IGBT lifetime by a factor of 2 to 3.

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Information about motor remagnetization and DC braking:

With a number of applications, for example, crane hoisting gear, elevators, cableways or cable liners, the drive is shut

down repeatedly at relatively short intervals by the issue of an inverter pulse disable command and the motor is reliably

halted by the sole action of mechanical holding brakes. To restart the drive, the mechanical holding brake is released

and the inverter pulse disable command is canceled. So that the motor can then produce the required torque as quickly

as possible, it is often remagnetized very rapidly. For this purpose, the shortest possible magnetizing time is selected

and the full overload capability of the inverter is utilized during remagnetization of the motor.

Every time the motor is remagnetized in this way, very high temperature swings occur as a result of the combination

of low output frequency and high current load and can have an extremely negative impact on the lifetime of the

IGBTs in the inverter in the applications described above. This is especially true when the application requires the

motor to be remagnetized rapidly at periodic intervals ranging from a few seconds to several minutes and, as regards

the configuring process, this scenario must be treated like a periodic load duty cycle with extremely high load

fluctuations.

In order to avoid a substantial reduction to the inverter IGBT lifetime with applications of this kind, a remagnetizing

period should be programmed that is long enough to ensure that the remagnetizing current does not exceed around

70 % of the inverter rated current. In applications for which an inverter pulse disable during standstill is not essential

for the process or for safety reasons, the inverter should continue to switch during the standstill period so that

remagnetization of the motor after restart becomes completely unnecessary.

The conditions associated with rapid remagnetization also occur in principle during DC braking when the motor needs

to be braked as quickly as possible through injection of a DC current. In the case of periodic braking operations, the

braking current should also be limited to a maximum of around 50 to 70 % of the rated current of the inverter.

Calculation example 1

A variable-speed drive must occasionally (around 3 times a day) perform a heavy duty start on a 690 V supply

system. The diagram below shows the motor current characteristic I(t) over time. The maximum ambient temperature

in the converter room is specified as 45 °C and the installation altitude is 400 m.

Motor current I(t) over time during starting

1. Select the converter

A SINAMICS G150 in degree of protection IP20 is selected as the drive converter. Its rated data are V = 690 V and

Irated = 575 A. It has, according to the Catalog D11, a base load current IH of 514 A and therefore a short-time current

IShortTime of 1.5 * IH = 771 A. We shall now use a calculation to check whether the selected converter operating on the

factory-set pulse frequency is capable of occasionally performing the required heavy duty start under the specified

conditions:

2. Determine the current derating factor kD:

With the following derating factors

· k

Temp = 0.933 (ambient temperature 45 °C, installation altitude < 2000 m, degree of protection IP20),

· k

Pulse = 1.0 (factory-set pulse frequency)

· k

Parallel = 1.0 (no parallel connection of S120 Motor Modules)

· k

IGBT = 1.0 (not a periodic load duty cycle, but only an occasionally required overload)

the current derating factor kD is

93300101019330 ..... =×××=×××= IGBTParallelPulseTempD kkkkk .

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3. Determine the permissible short-time current:

With a base load current IH = 514 A and a derating factor kD = 0.933, the permissible short-time current is

AAIkI HDShortTime 72051493305151 =××=××= ... .

This value corresponds to the motor current of 720 A required at the beginning of the heavy duty start and is

therefore just within the permissible limit.

4. Determine the I2t value of the motor current:

For the purpose of simplifying the calculation, the actual time characteristic of the motor current I(t) during starting is

approximated by three time phases, i.e. T1 to T3, each with a constant current I1 to I3. In this case, the last phase T3

must be selected such that the total of phases T1+T2+T3 does not exceed the maximum permissible load duty cycle

duration of T=300 s. The calculation for the I2t value is therefore

é×

+×

×= 3

21T

valuetI

DRatedDRatedDRated

• 100 %

é×

+×

×= s

valuetI 120

536

250

536

500

120

536

720

300

1222

2• 100 %

[ ]

%%% 98100

300

295

1002652217

300

2=×=×++×= s

sss

valuetI

The calculated I2t value of 98 % is slightly lower than the permissible value of 100 % and is thus just about

acceptable within the limits of accuracy of the approximations used to calculate the current characteristic over time.

Note about calculation example 1:

In addition to the motor current characteristic over time I(t) as shown by the blue curve, the characteristic of the junction

temperature over time Tj(t) of the IGBT chips in the power unit is also shown by the black curve in the diagram below.

Time characteristic of the motor current I(t) and the junction

temperature Tj(t) of the IGBT chips during starting

It is apparent from the diagram that very high temperature fluctuations occur in the IGBT at the beginning of the

startup process as a result of the initially very low converter output frequency combined with the very high output

current. This phenomenon is described in section "Power cycling capability of IGBT modules and inverter power

units". These temperature fluctuations in the IGBT increasingly decrease during startup because the output frequency

is continuously rising on the one hand, and the output current also drops towards the end of the startup process on

the other. The peak values of the junction temperature Tj of the IGBT chips remain just below the permissible limit of

150° C at the beginning of the startup process which means that the selected converter doesn't quite reach the limits

of its thermal load capacity during startup and the triggering of an overload reaction is therefore narrowly avoided.

Provided that the unit is operated only occasionally for periods of less than around 2 % of the total operating time of

the drive with temperature fluctuations of this magnitude caused by a combination of low output frequencies and high

output currents (as is the case with this example), the only essential configuring requirement is to ensure that the

maximum permissible chip temperature in the IGBT is not exceeded. The influence of temperature fluctuations on the

IGBT lifetime can be ignored in this instance, i.e. kIGBT = 1.

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However, if the drive is required to operate periodically with high temperature fluctuations of this magnitude caused

by severe load fluctuations and/or a combination of low output frequencies and high output currents, the influence of

temperature fluctuations on the lifetime of the IGBTs must be taken into account as a configuring factor, i.e. the

fluctuations must be limited to permissible values by the application of derating factors, as demonstrated by the

example below.

Calculation example 2:

A SINAMICS S150 converter in degree of protection IP20 is to be operated as a centrifuge drive on a 400 V supply

system at a maximum ambient temperature of 40 °C at a maximum installation altitude of 1000 m. The motor current

I(t) and motor frequency f(t) over time are shown in the diagram below. In continuous batch process without

downtimes, therefore, the converter operates according to a regularly recurrent, periodic load duty cycle. The

converter is to be operated at the factory-set pulse frequency in vector control mode (drive object of Vector type).

T1 : Fill centrifuge

T2 : Accelerate to spin speed

T3 : Spin at spin speed

T4 : Decelerate to emptying speed

T5 : Empty centrifuge

T: Load cycle duration (T = T1 + T2 + T3 + T4 + T5)

Absolute value of motor current |I(t)| and motor frequency f(t)

1. Select the converter:

According to the diagram shown above, the converter must be capable of supplying a short-time current IShortTime of

520 A. It therefore requires a base load current IH of at least

IShortTime / 1.5 = 520 A / 1.5 = 347 A.

For this reason, a converter rated for V = 400 V and Irated = 490 A is selected which, according to catalog D 21.3, has

a base load current IH of 438 A and thus a short-time current IShortTime of 1.5 * IH = 657 A. The factory-set pulse

frequency for vector control mode is 2 kHz. We shall now use a calculation to determine whether the selected

converter is suitable for the required periodic load duty cycle operating on the factory-set pulse frequency under the

conditions specified above.

2. Determine the current derating factor kD:

· k

Temp : 1.0 (ambient temperature ≤ 40 °C, installation altitude < 1000 m, degree of protection IP20),

· k

Pulse : 1.0 (factory-set pulse frequency)

· k

Parallel : 1.0 (not a parallel connection of S120 Motor Modules)

· k

IGBT : This factor must be taken into account because of the periodic load duty cycle. According to the

diagram above, the following applies:

- Current ratio ΔI = IShortTime / IBaseLoad = 520 A / 115 A = 4.52 ≈ 4.5.

- Load duty cycle duration T = 300 s.

With ΔI ≈ 4.5 and T = 300 s, the derating factor is according to derating characteristic 3 which is

applicable to the SINAMICS S150 converter with V = 400 V and Irated = 490 A: kIGBT = 0.8.

The current derating factor kD is therefore calculated as follows:

8080010101 ..... =×××=×××= IGBTParallelPulseTempD kkkkk .

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3. Determine the permissible short-time current:

With a base load current IH = 438 A and a derating factor kD = 0.8, the permissible short-time current is

AAIkI HDTimeShort 5254388.05.15.1 =××=××= .

This value is slightly higher than the required maximum motor current of 520 A and is thus permissible.

4. Determine the I2t value of the motor current:

According to the time characteristic of the motor current as shown by the diagram above, the I2t value is

é×

+×

×= 5

21T

valuetI

DRatedDRatedDRatedDRatedDRated

• 100 %

é×

+×

×= s

valuetI 60

392

350

392

520

392

115

392

520

392

115

300

122222

2• 100 %

[ ]

%%%..... 90100

300

270

100847610525610525

300

2=×=×++++×= s

sssss

valuetI .

The calculated I2t value of 90 % is below the acceptable value of 100 % and is therefore permissible.

5. Determine the permissible current during interval T5:

During interval T5 the converter is operated at an output frequency of 5 Hz, a frequency which is lower than 10 Hz.

Since the duration of this interval is 60 s and it occurs periodically in a 300 s cycle, it corresponds to 20 % of the total

operating period and is thus significantly higher than 1 % to max. 2 % of the total operating period of the centrifuge.

Therefor the derating characteristic described in subsection "Operation without overload with frequent periods of low

output frequencies < 10 Hz" in section "Power cycling capability of IGBT modules and inverter power units" must

therefore be applied to interval T5:

Permissible output current with frequent periods of low

output frequencies as a function of output frequency

According to this derating characteristic, the converter may be operated at a maximum of only 90 % of its rated

current during operation with 5 Hz if premature failure of the unit is to be avoided. The permissible current during

interval T5 is thus calculated as follows:

AAITI Rated 4414909.09.0)( 5

This value is higher than 350 A. The converter may therefore be operated continuously with 350 A at 5 Hz during

interval T5 within the periodic load duty cycle T.

The selected SINAMICS S150 converter rated for V = 400 V and Irated = 490 A is thus suitable for the centrifuge

application with the given periodic load duty cycle provided it is operated at the factory-set pulse frequency.

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Note about calculation example 2:

In addition to the absolute motor current value |I(t)| as shown by the blue curve and the motor frequency f(t) as shown

by the red curve, the characteristic of the junction temperature over time Tj(t) of the IGBT chips in the power unit is

also shown by the black curve in the diagram below.

Absolute value of motor current |I(t)|, motor frequency f(t) and characteristic of junction temperature

over time Tj(t) of the IGBT chips during the periodic load duty cycle of the centrifuge

With the peak values of the junction temperature Tj of the IGBT chips measuring around 105° C, it is clear that they

are well below the permissible limit of 150° C in this periodic load duty cycle. But the temperature fluctuations in the

IGBT are relatively high as a result of two effects. One effect is the very high variations in current which occur

alternately in the different phases of the load duty cycle (low current during filling and spinning, high current during

acceleration and braking), and the other effect is the relatively long discharge phase which is characterized by a

combination of low output frequency and relatively high current.

Both effects have been taken into account in this example by the application of the correct derating factors with the

result that the temperature fluctuations of around 35°C remain within acceptable limits with respect to preservation of

the IGBT lifetime.

In order to minimize to the greatest possible extent the inevitable temperature fluctuations which occur as a result of

load changes within a load duty cycle, it is advisable in this instance to configure the drive according to the criteria

described above and also to note the following additional points at the commissioning stage because the result of the

configuring calculation of the current derating factor kIGBT is 0.8 < 1.0:

The drive must be commissioned with the configured pulse frequency (which corresponds to the factory setting in this

example), or with meaningfully selected, current-dependent switchover between different pulse frequencies.

Current-dependent switchover between different pulse frequencies is the best solution for achieving an additional

reduction in the temperature swings ΔTChip. This is because the temperature rise can be minimized by operating the

converter on a very low pulse frequency in operating states with very high current (acceleration phase T2 and

deceleration phase T4). In operating states with very low current (filling phase T1 and spinning phase T3), the

temperature reduction can be minimized by operating the converter on a very high pulse frequency. By using

switchover between different pulse frequencies as a function of current, it is possible to reduce temperature

fluctuations and thus prolong the lifetime of the IGBTs.

Furthermore, the temperature fluctuations caused by the low output frequency during the discharge phase T5 should

be minimized through selection of the low pulse frequency corresponding to the factory setting and by attempting

(within the limits imposed by the process) to keep the output frequency as high as possible during the discharge

phase T5 and setting the output current to the lowest possible value. Even very small increases in the output

frequency, e.g. from 5 Hz to 7 Hz, or minor reductions by a few 10 A in the output current can effect a substantial

reduction in the temperature fluctuations in this instance.

The configured pulse frequency should never be generally increased independently of the different load conditions

using an overload reaction with pulse frequency reduction (p290 = 2 or 3). Because, when combined with an

increased pulse frequency, high currents trigger an overload reaction very quickly owing to the high power losses.

However, this overload reaction is not triggered until the IGBT chip temperature reaches a very high level in order to

allow operation of the power unit at the increased pulse frequency for as long as possible. This mode of operation

with temperature-dependent pulse frequency switchover therefore maximizes the temperature swings ΔTChip in the

IGBTs. With load duty cycles involving substantial load current fluctuations – of the type characteristic of this example

with ΔI = 4.5 – this mode of operation is not a suitable method of reducing temperature fluctuations or prolonging the

life of the IGBTs.

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Calculation example 3

A SINAMICS S150 converter in degree of protection IP20 is to be operated as a flywheel press drive on a 690 V

supply system at a maximum ambient temperature of 40 °C and at a maximum installation altitude of 1000 m. The

motor current I(t) (blue curve) and the motor frequency f(t) (red curve) over time are illustrated in diagram 1. The

flywheel is started up and accelerated to operating speed during phase T1. In steady-state press operation T2 the

flywheel is braked and accelerated again periodically. At the end of the period of steady-state press operation, the

flywheel is decelerated and finally stopped during phase T3. The converter is to be operated at the factory-set pulse

frequency in vector control mode (vector-type drive object).

T1 : Startup (acceleration) of the flywheel

T2 : Steady-state, periodic press operation

T3 : Stop (braking) of the flywheel

Diagram 1: Absolute value of motor current |I(t)| and motor frequency f(t)

1. Select the converter:

According to diagram 1, the converter must be capable of supplying a short-time current IShortTime of 730 A. It therefore

requires a base load current IH of at least

IShortTime / 1.5 = 730 A / 1.5 = 487 A.

For this reason, a converter rated for V = 690 V and Irated = 575 A is selected which, according to catalog D 21.3, has

a base load current IH of 514 A and thus a short-time current IShortTime of 1.5 * IH = 771 A. The factory-set pulse

frequency for vector control mode is 1.25 kHz.

We shall now use a calculation to determine whether the selected converter is suitable to operate as the press drive

on the factory-set pulse frequency under the conditions specified above.

2. Analyze the steady-state, periodic press operation during phase T2:

2.1. Determine the current derating factor kD during phase T2:

· k

Temp : 1.0 (ambient temperature ≤ 40 °C, installation altitude < 1000 m, degree of protection IP20),

· k

Pulse : 1.0 (factory-set pulse frequency)

· k

Parallel : 1.0 (not a parallel connection of S120 Motor Modules)

· k

IGBT : This factor must be taken into account owing to the periodic press operation during phase T2.

According to diagram 1, the following apply during phase T2:

- Current ratio ΔI = IShortTime / IBaseLoad = 400 A / 150 A = 2.67.

- Load duty cycle duration T = T21 + T22 = 20 s.

With ΔI = 2.67 and T = 20 s, the derating factor is according to the derating characteristic 1 which is

applicable to the SINAMICS S150 converter with V = 690 V and Irated = 575 A: kIGBT = 0.96.

The current derating factor kD is therefore calculated as follows:

96.096.00.10.10.1 =×××=×××= IGBTParallelPulseTempD kkkkk .

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2.2. Determine the permissible short-time current during phase T2:

With a base load current IH = 514 A and a derating factor kD = 0.96, the permissible short-time current is

AAIkI HDShortTime 74051496.05.15.1 =××=××= .

This value is significantly higher than the required maximum motor current of 400 A during steady-state, periodic

press operation during phase T2 and is therefore permissible.

2.3. Determine the I2t value of the motor current during phase T2:

According to the time characteristic of the motor current as shown in diagram 1, the I2t value is

é×

+×

=22

2221

21504001 T

valuetI

DRatedDRated

• 100 %

é×

+×

valuetI 10

552

150

552

400

1010

122

2• 100 %

[ ]

%30%100

99.5

%100738.025.5

2=×=×+×= s

valuetI .

The calculated I2t value of 30 % is well below 100 % and is therefore permissible.

Steady-state, periodic press operation during phase T2 is thus permissible both in terms of the short-time current and

in terms of the I2t value.

3. Analyze the startup and shutdown behavior of the flywheel:

As a general rule, the flywheel is rarely started up and stopped while a press is in production. It is therefore easy to

imagine that these processes are rare events which have no relevance with regard to the lifetime of the IGBTs in the

power unit.

In practice however, long phases of operation during which the flywheel is periodically started up and stopped over

periods lasting hours or even days may be necessary during setup mode after a tool change or with tryout presses in

which new tools are tried out. This example application may therefore involve periodic operating conditions as shown

in diagram 2 which can lead to substantial temperature swings ΔTChip in the IGBT and therefore significantly reduce

the IGBT lifetime.

T0 : Standstill of the flywheel

T1 : Startup (acceleration) of the flywheel

T2 : Brief press operation with a few strokes

T3 : Stop (braking) of the flywheel

Diagram 2: Absolute value of motor current |I(t)| and motor frequency f(t)

With periodic startup and shutdown of the flywheel

If it has to be assumed that these periodic operating conditions occur for more than around 1 to 2 % of the total

operating time of the press (which is true in the case of many flywheel presses), it must be categorized as a periodic

load duty cycle. The current derating factor kIGBT must therefore be applied when the drive is configured in order to

prevent premature failure of IGBTs.

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3.1. Determine the current derating factor kD during startup and shutdown:

· k

Temp : 1.0 (ambient temperature ≤ 40 °C, installation altitude < 1000 m, degree of protection IP20),

· k

Pulse : 1.0 (factory-set pulse frequency)

· k

Parallel : 1.0 (not a parallel connection of S120 Motor Modules)

· k

IGBT : This factor must be taken into account because the press is periodically started up and shut down.

According to diagram 2, the following apply:

- Current ratio ΔI = IShortTime / IBaseLoad = 730 A / 150 A = 4.87.

- Load duty cycle duration T = T0 + T1 + T2 +T3 = 120 s.

With ΔI = 4.87 and T = 120 s, the current derating factor is according to derating characteristic 1

which is applicable to the SINAMICS S150 converter with V = 690 V and Irated = 575 A: kIGBT = 0.91.

The current derating factor kD is therefore calculated as follows:

91.091.00.10.10.1 =×××=×××= IGBTParallelPulseTempD kkkkk .

3.2. Determine the permissible short-time current during periodic startup and shutdown:

With a base load current IH = 514 A and a derating factor kD = 0.91, the permissible short-time current is

AAIkI HDShortTime 70251491.05.15.1 =××=××= .

This value is lower than the required maximum motor current of 730 A during periodic startup and shutdown and is

therefore not permissible in terms of preserving the IGBT lifetime.

As a result, the initially selected converter rated for V = 690 V and Irated = 575 A, which has a base load current IH of

514 A and thus a short-time current IShortTime of 1.5 • IH = 771 A according to catalog D 21.3, is not suitable for the

purpose of ensuring an acceptable IGBT lifetime.This means that the next larger size of converter rated for V = 690 V

and Irated = 735 A must be used which also has a factory-set pulse frequency in vector control mode of 1.25 kHz. The

calculation must be checked according to the same principle described above (determination of the short-time current

and I2t calculation). This calculation is not presented in detail here, but confirms that the new converter has been

correctly selected.

Note about calculation example 3:

In order to minimize to the greatest possible extent the inevitable temperature fluctuations which occur as a result of

load changes within a load duty cycle, it is advisable in this instance to configure the drive according to the criteria

described above and also to note the following additional points at the commissioning stage because the result of the

configuring calculation of the current derating factor kIGBT is < 1.0:

The drive must be commissioned with the configured pulse frequency (which corresponds to the factory setting in this

example), or with meaningfully selected, current-dependent switchover between different pulse frequencies.

Current-dependent switchover between different pulse frequencies is the best solution for achieving an additional

reduction in the temperature swings ΔTChip. This is because the temperature rise can be minimized by operating the

converter on a very low pulse frequency (factory setting) in operating states with very high current. In operating states

with very low current, the drop in temperature can be minimized by operating the converter at a very high pulse

frequency. By using switchover between different pulse frequencies as a function of current, it is possible to reduce

temperature fluctuations and thus prolong the lifetime of the IGBTs.

The configured pulse frequency should never be generally increased independently of the different load conditions

using an overload reaction with pulse frequency reduction (p290 = 2 or 3). Because, when combined with an

increased pulse frequency, high currents trigger an overload reaction very quickly owing to the high power losses.

However, this overload reaction is not triggered until the IGBT chip temperature reaches a very high level in order to

allow operation of the power unit at the increased pulse frequency for as long as possible. This mode of operation

with temperature-dependent pulse frequency switchover therefore maximizes the temperature swings ΔTChip in the

IGBTs. With load duty cycles involving substantial load current fluctuations – of type characteristic of this example –

this mode of operation is not a suitable method of reducing temperature fluctuations or prolonging the life of the

IGBTs.

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1.13.4 Thermal monitoring of the power unit

In both continuous operation and load duty cycle mode, the power unit of the SINAMICS converters G130, G150,

S150 and S120 Motor Modules (Chassis and Cabinet Modules) is thermally monitored by three different methods:

· The output current is monitored by an I2t calculation.

· The heatsink temperature is monitored by direct temperature measurements.

· The chip temperature of the IGBTs is monitored by the thermal model which can calculate the exact

temperature of the IGBT chips on the basis of the heatsink temperature measurement plus other electrical

quantities such as pulse frequency, DC link voltage and output current.

If a power unit overload is detected by these monitoring functions, an "overload reaction" defined by the setting in

parameter p0290 is triggered. The following overload reactions can be parameterized in p0290:

0: Reduce output current or output frequency.

1: No reduction / shutdown (trip) when the overload threshold is reached.

2: Reduce output current or output frequency and pulse frequency (not by I2t).

3: Reduce pulse frequency (not by I2t).

With many applications, the parameterizable overload reaction makes it possible to prevent instantaneous shutdown

when the power unit is overloaded briefly. For example, it is perfectly tolerable with most pump and fan applications

for the flow rate to drop briefly when the output current is reduced. If the drive is operating on a higher pulse

frequency than the factory setting in order to achieve a reduction in motor noise, for example, a possible overload

reaction would be to reduce the pulse frequency and thus maintain the flow rate.

If the parameterized overload reaction cannot reduce the overload sufficiently, then the drive will always shut down in

order to protect the power unit. This means that the risk of irreparable damage to the power unit as a result of

excessive IGBT temperatures is absolutely eliminated in all operating modes.

These protection mechanisms implemented in the SINAMICS units do, however, demand precise configuring of the

converter in relation to its load profile so that the drive can perform all the required functions without being interrupted

by overload reactions.

1.13.5 Operation of converters at increased pulse frequency

The technical data in the catalogs and operating instructions, in particular

· the rated output current Irated,

· the base load currents IL and IH

and their associated short-time currents according to the load duty cycle

definitions,

· the maximum output current Imax,

· and the specified output power ratings

always refer to converter or inverter operation at the factory-set pulse frequency.

If the pulse frequency is increased above the factory-set value on G130, G150 and S150 converters or S120

inverters (Chassis and Cabinet Modules), the switching losses in the inverter rise in proportion to the pulse frequency

which generally results in thermal overloading of the power unit when the inverter is operating at full capacity.

Various strategies can be used to prevent the power unit from overheating when the pulse frequency is increased.

These depend on the overload reaction setting in parameter p0290 and they are described below.

It must be noted that the current derating factors kPulse for increased pulse frequencies which are specified in the

sections on specific unit types are generally omitted from the I2t calculation for monitoring the utilization of the

inverter. This means that all currents, i.e. the rated output current Irated, the base load currents IL and IH, and the

maximum output current Imax remain unchanged and can thus be utilized in the first instance at increased pulse

frequencies. This means basically that the inverter can be utilized with respect to current limits as if it were operating

at the factory-set pulse frequency.

For thermal reasons, however, this is true only on the condition that the unit is operated at the relevant currents for

only brief periods or that the values of the influencing parameters described further below, such as ambient

temperature, are favorable enough.

Since the current derating factors kPulse for increased pulse frequencies are omitted from the I2t calculation for

monitoring the utilization of the inverter, the inverter is practically protected in operation at increased pulse frequency

only by the monitoring systems for the heat sink temperature and chip temperature of the IGBTs.

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1. Overload reactions without reduction in pulse frequency (p0290 = 0 or 1)

In this case, reduction of the increased pulse frequency is not possible as an overload reaction. The only two possible

reactions are to reduce the output current of the inverter (p0290 = 0) or trip the inverter immediately (p0290 = 1).

These overload reactions must be selected, for instance, if the high output frequency requirements of the drive

application in question exclude the option of a pulse frequency reduction or if the use of a sine-wave filter means that

the pulse frequency may not be changed.

However, overload reactions which do not involve a pulse frequency reduction constitute a substantial intervention in

the proper functioning of the drive system for virtually all types of applications. The system must therefore be

configured appropriately to reliably prevent overload reactions of this type.

This can be achieved by reducing the conducting losses, i.e. by lowering the output current (current derating), in

order to compensate for the higher switching losses caused by the increased pulse frequency.

The current derating factors kPulse, which are specified for various pulse frequencies in the sections on specific unit

types, must be applied for both continuous operation and load duty cycle operation for this purpose when the system

is configured. If current derating factors kPulse are required for pulse frequencies which are not included in the tables,

they can be calculated by linear interpolation between the stated table values.

For steady-state continuous operation the rated output current Irated must be reduced by the current derating factor

kPulse. For load duty cycles, the base load currents IL and IH

, as well as the maximum output current Imax, must be

reduced by the current derating factor kPulse.

By using this configuring approach, it is possible to reliably prevent thermal overloading of the power unit as a result

of the increased pulse frequency and to safely exclude the risk of intervention by the overload reaction.

2. Overload reactions with reduction in pulse frequency (p0290 = 2 or 3)

In this case, the initial overload reaction is to reduce the inverter pulse frequency and, if this is not sufficient, to

reduce the output current as well (p0290 = 2). An alternative is to reduce only the pulse frequency (p0290 = 3). It

must be noted that the pulse frequency can only be reduced by a factor of two.

The factory-set overload reaction for drives with vector or V/f control mode (drive objects of vector type) is p0290 = 2.

Note: For drives with servo control mode (drive objects of servo type), automatic pulse frequency switchover as part

of the overload reaction is not possible.

These overload reactions can be utilized meaningfully, for example, if the increased pulse frequency is used solely to

reduce motor noise in applications with low control requirements and an occasional intervention by an overload

reaction is thus easily tolerated by the drive or process.

Overload reactions involving a reduction in pulse frequency do not constitute a significant intervention in normal drive

operation. Nevertheless, the drive should be configured such that the risk of initiation of such reactions is minimized

or ideally eliminated completely.

This can be achieved basically by reducing the conducting losses, i.e. by lowering the output current, in order to

compensate for the higher switching losses caused by the increased pulse frequency. The current derating factors

kPulse given in the sections on specific unit types for both continuous operation and load duty cycle operation must be

initially applied for this purpose when the drive is configured.

With overload reactions involving pulse frequency reduction, it is possible to make beneficial use of the fact that the

current derating factors kPulse are dependent on several influencing parameters which have more favorable values in

many applications than those on which the current derating factors kPulse are based on. The influencing parameters

and their values included in the current derating factors kPulse are as follows:

·Line voltage VLine:

Accounted for in kPulse:Maximum line voltage

·Ambient temperature TA:

Accounted for in kPulse:Maximum ambient temperature of 40 °C

·Minimum operational output frequency fOut-min:

Accounted for in kPulse:Minimum operational output frequency of 10 Hz

When the influencing parameters have different values (e.g. low line voltage, low ambient temperature or relatively

small speed setting range with high, minimally used output frequency), the current derating factors kPulse for pulse

frequencies corresponding to twice the factory setting can be reduced as a function of the influencing parameters,

which means that current derating for pulse frequencies corresponding to twice the factory setting can be partially or

completely avoided.

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The procedure for air-cooled converters and inverters is described below (liquid-cooled inverters on request).

The current derating factor kPulse-2x to be applied practically in the case of pulse frequencies corresponding to twice

the factory setting is calculated on the basis of the relevant current derating factor kPulse given for pulse frequencies

equal to twice the factory setting in the sections on specific unit types according to the formula

æ-

×+×

-°

×+×

æ-

×+×= -

-Hz

Hzf

kk OutA

Line

LineLine

PulsexPulse 50

05.01

2.015.01 min

max

Key to formula:

· k

Pulse-2x Current derating factor to be applied practically for pulse frequencies equalling twice the factory

setting.

· k

Pulse Current derating factor according to the tables in sections on specific unit types for pulse

frequencies equaling twice the factory setting.

· V

Line-max Maximum line voltage:

480 V for units with line supply voltage ranges: 380 V – 480 V 3AC

510 V – 720 V DC

690 V for units with line supply voltage ranges: 500 V – 600 V 3AC

660 V – 690 V 3AC

500 V – 690 V 3AC

675 V -1035 V DC

· V

Line Line voltage at installation site.

· T

AAmbient temperature at installation site:

Permissible value range within the limits of the above formula: TA = 10 °C – 40 °C.

· f

Out-min Minimum operational output frequency:

Permissible value range within the limits of the above formula: fOut-min =10 Hz – 50 Hz.

Notes:

· The calculation formula is valid only for pulses frequencies which equal twice the factory setting. For higher

pulse frequencies, the current derating factors in the sections on specific unit types must be applied

unchanged. This is because the current derating factors can be reduced as a function of influencing

parameters to only a minimal degree for these pulse frequencies and the effect is generally negligible.

· In applications where the values of the influencing parameters are so favorable as to give a current derating

factor kPulse-2x > 100 %, then kPulse-2x = 100 % must be set, because it is fundamentally impossible to

operate inverters continuously on currents higher than Irated due to the I2t monitoring function.

· If the system reacts to overload with a pulse frequency reduction, e.g. because the configured ambient

temperature is exceeded temporarily, the pulse frequency switchover will cause certain transient

phenomena in the current and torque similar in nature to the effects of the pulse pattern switchover between

space vector modulation SVM and pulse-edge modulation PEM. The drive must have the control capability

to withstand these transient phenomena. For this reason, overload reactions with pulse frequency reduction

are more appropriate for applications for which control quality is less critical, e.g. pump and fan drives.

Otherwise, the drive must be engineered in such a way as to guarantee that the conditions which would

allow the overload reaction to intervene in normal drive operation can never be fulfilled.

· With respect to periodic load duty cycles, it must be noted that high currents up to the maximum current Imax

combined with increased pulse frequencies trigger an overload reaction very quickly owing to the high power

losses, resulting in periodic switchover between pulse frequencies accompanied by very high temperature

swings ΔTChip in the IGBTs and therefore ultimately to premature failure of the power units. When periodic

load duty cycles with high overload are configured therefore, we urgently recommend application of the

current derating factors kPulse as specified in the tables in the sections on specific unit types and advise that

overload reactions with temperature-dependent reduction in the pulse frequency (p290 = 2 or 3) should not

be used. This applies in particular if the current derating factor kIGBT is calculated to be < 1.0 when the drive

is configured as described in section "Free load duty cycles".

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Example calculation:

A pump drive is to be supplied by a SINAMICS G150 converter. The drive is supplied by a line voltage of 500 V and

operated at a maximum ambient temperature of 30°C. The speed setting range is relatively small, which means that

the drive utilizes only the output frequency range from 30 Hz to 50 Hz in operation. A SINAMICS G150 with an output

power of 200 KW at 500 V is required to meet the relevant load requirements. This device has a rated output current

of 330 A at the factory-set pulse frequency of 1.25 kHz.

The motor needs to run as quietly as possible which means that a pulse frequency of at least 2.5 kHz is required.

It is necessary to determine whether or by how much the converter needs to be overdimensioned if it is to be

operated with the factory-set overload reaction p0290 = 2 at a pulse frequency of 2.5 kHz under the conditions stated

above.

The current derating factor kPulse-2x to be applied practically is calculated according to the formula

æ-

×+×

-°

×+×

æ-

×+×= -

-Hz

Hzf

kk OutA

Line

LineLine

PulsexPulse 50

05.01

2.015.01 min

max

With the given values

· k

Pulse = 82 %

(according to the derating table in chapter "Converter Cabinet Units SINAMICS G150“),

· V

Line-max = 690 V for SINAMICS G150 with the line supply voltage range 500 V – 600 V 3AC,

(according to key to calculation formula on the previous page),

· V

Line = 500 V,

· T

= 30°C

and

· f

Out-min = 30 Hz

the result is

æ-

×+×

°-°

×+×

æ-

×+×=

-Hz

HzHz

kxPulse 50

1030

0501

3040

201

690

500690

50182

2...%

(

)

(

)

(

)

021051138182

2...% ×××=

-xPulse

219182

2.%×=

-xPulse

%.9699

-xPulse

Where the current derating factor to be practically applied is kPulse-2x = 99.96 % (or almost 100 %), no current derating

is effectively required in operation at a pulse frequency of 2.5 kHz. This means that the converter can operate

continuously at its rated output current of 330 A, making overdimensioning unnecessary.

Even if once briefly in operation the ambient temperature of 30 C were to be exceeded or the frequency were to drop

below the minimum operational output frequency of 30 Hz, the system would only react to the overload by reducing

the pulse frequency to the factory setting of 1.25 kHz. The drive could therefore continue to function normally. The

only negative, but nevertheless generally acceptable effect, would be an increase in motor noise during the period of

pulse frequency reduction.

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1.14 Efficiency of SINAMICS converters at full load and at partial load

In many applications energy savings can be made by the use of variable-speed drives instead of conventional drive

solutions. Significant energy savings can be achieved with variable-speed drive systems in partial-load operation,

particularly if they are used to drive pumps and fans with a quadratic load characteristic. Systems of this type produce

very low losses over a wide speed range and are therefore very efficient. In order to be able to quantify these

savings, precise information is needed about the losses and efficiency of the converter and motor as a function of

load and speed.

For this reason, the converter losses and efficiency values for all SINAMICS units described in this engineering

manual are specified below for full-load and partial-load operation.

Note:

The calculation of partial-load losses and efficiency values is based on a calculation method specifically devised for

SINAMICS units. Using this method, it is possible to obtain a sufficiently accurate result for all SINAMICS devices

with just a small quantity of device-specific data and relatively little work. The result can be used as a reliable basis

for performing other configuring tasks such as calculating air-conditioning requirements. In its methodology, however,

this procedure deviates from the European standard EN 50598 which came into force in 2015 and outlines eco-

compatible design requirements (energy efficiency, eco-balance calculations) for electrical drive systems (motor

systems / Power Drive Systems (PDF)) in electrically driven machines in the low-voltage range. The results may

deviate in some respect from those defined by EN 50598.

Definition of efficiency

Efficiency is defined as the ratio between the active electrical power supplied at the output POut and the active

electrical power drawn at the input PIn. If the fact is taken into account that the active electrical power drawn at the

input PIn is higher than the active electrical power supplied at the output POut by a factor corresponding to the power

losses PL, then the following general formula can be applied to calculate the efficiency η:

LOut

Out

.(1)

1.14.1 Converter efficiency at full load

The converter efficiency η100 at full load is calculated on the basis of converter operation with a motor which has been

matched to the rated data of the converter in terms of its rated voltage and rated current, and which is operating at its

nominal working point. In order to calculate the efficiency η100 at this rated point, the active power at the output of the

converter POut-100 and the power losses of the converter PL-100 must be specified.

The active electrical power POut-100 supplied at the converter output at full load is

MotOutOutOut IVP

cos3 100100100 ×××= --- .

The output voltage VOut-100 of SINAMICS converters in vector control mode is, when operating with pulse-edge

modulation, almost equal to the line supply voltage VLine on the input side. The output current IOut-100 is the rated

output current IOut-rated of the converter and the power factor cosφMot is the power factor of a motor which has been

matched to the rated data of the converter in terms of its rated voltage and rated current, and which is operating at its

nominal working point. Thus, at full load, the active power at the output of the converter is

MotratedOutLineOut IVP

cos3

100 ×××» -- (2)

The power losses PL-100 of the converters at full load are device-specific values and can be found either in the

Catalogs D 11 or D 21.3 or in the operating instructions (equipment manuals).

The efficiency of the converter η100 at full load is calculated on the basis of the active electrical output over POut-100

and the power losses PL-100 according to the formula

( )

100

100100

100

100 cos3

cos3

+×××

×××

LMotratedOutLine

MotratedOutLine

LOut

Out

PIV

. (3)

This formula can be applied to individually calculate the full load efficiency of the SINAMICS converters as a function

of the line voltage and the power factor of the connected motor.

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If the efficiency calculation for SINAMICS converters is performed on the basis of a typical power factor of

cosφMot = 0.88 (4-pole asynchronous motors in the power range from 100 kW to 1000 kW), the following typical

converter efficiency factors at full load are obtained:

· SINAMICS G130 and G150 with pulse frequency according to factory settings: η100 = 97.7 % - 98.3 %.

· SINAMICS S150 with pulse frequency according to factory settings: η100 = 96.0 % - 96.5 %.

1.14.2 Converter efficiency at partial load

1.14.2.1 – – –

1.14.2.2 Partial load efficiency of S120 Basic Line Modules

The chart below shows the partial-load efficiency of air-cooled and liquid-cooled SINAMICS S120 Basic Line

Modules. The calculations are based on a typical efficiency at full load of 99 %. The efficiency is represented as a

function of the active output power ratio POut/POut-100 supplied by the BLM to the connected SINAMICS S120 Motor

Modules.

Efficiency of air-cooled and liquid-cooled S120 Basic Line Modules

as a function of the active output power ratio POut/POut-100 in %

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1.14.2.3 Partial load efficiency of S120 Smart Line Modules

The chart below shows the partial-load efficiency of air-cooled SINAMICS S120 Smart Line Modules.The calculations

are based on a typical efficiency at full load of 98.5 %. The efficiency is represented as a function of the active output

power ratio POut/POut-100 supplied to the connected SINAMICS S120 Motor Modules by the SLM or drawn from the

connected SINAMICS S120 Motor Modules by the SLM and regenerated to the mains supply.

Efficiency of air-cooled S120 Smart Line Modules as a

function of the active output power ratio POut/POut-100 in %

1.14.2.4 Partial load efficiency of S120 Active Line Modules + Active Interface Modules

The chart below shows the partial-load efficiency of air-cooled and liquid-cooled SINAMICS S120 Active Line

Modules including the assigned air-cooled Active Interface Modules. The calculations are based on typical efficiency

values at full load. These are 98.5 % with Active Line Modules and 99 % with the assigned Active Interface Modules,

corresponding to a total efficiency η100-(ALM+AIM) = 97.5 %. The efficiency is represented as a function of the active

output power ratio POut/POut-100 supplied to the connected SINAMICS S120 Motor Modules by the ALM+AIM or drawn

from the connected SINAMICS S120 Motor Modules by the ALM+AIM and regenerated to the mains supply.

Efficiency of air-cooled and liquid-cooled S120 Active Line Modules including the assigned

air-cooled Active Interface Modules as a function of the active output power ratio POut/POut-100 in %

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1.14.2.5 Partial load efficiency of S120 Motor Modules

The charts below show the partial-load efficiency of air-cooled SINAMICS S120 Motor Modules for constant-torque

drives. The calculations are based on a typical efficiency at full load of 98.5 %. The efficiency is represented in two

different ways. In one chart, the efficiency is shown as a function of the output frequency with the output current as a

parameter, and in the second chart, as a function of the output current with the output frequency as a parameter.

Figure 1a) shows the characteristic curve of the efficiency for constant-torque drives as a function of the output

frequency ratio fOut/fOut-rated which is proportional to the motor speed ratio n/nrated. The parameter for the family of

curves is the output current ratio IOut/IOut-rated which is proportional to the motor torque ratio M/Mrated.

Figure 1a)

Efficiency of air-cooled SINAMICS S120 Motor Modules in constant-torque drives

as a function of the output frequency ratio in %

Figure 1b) shows the characteristic curve of the efficiency for constant-torque drives as a function of the output

current ratio IOut/IOut-rated which is proportional to the motor torque ratio M/Mrated. The parameter for the family of

curves is the output frequency ratio fOut/fOut-rated which is proportional to the motor speed ratio n/nrated.

Figure 1b)

Efficiency of air-cooled SINAMICS S120 Motor Modules in constant-torque drives

as a function of the output current ratio in %

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1.14.2.6 Partial load efficiency of G130 / G150 converters

The charts below show the partial-load efficiency of SINAMICS G130 and G150 converters for constant-torque

drives. The calculations are based on a typical efficiency at full load of 98 %. The efficiency is represented in two

different ways. In one chart, the efficiency is shown as a function of the output frequency with the output current as a

parameter, and in the second chart, as a function of the output current with the output frequency as a parameter.

Figure 1a) shows the characteristic curve of the efficiency for constant-torque drives as a function of the output

frequency ratio fOut/fOut-rated which is proportional to the motor speed ratio n/nrated. The parameter for the family of

curves is the output current ratio IOut/IOut-rated which is proportional to the motor torque ratio M/Mrated.

Figure 1a)

Efficiency of SINAMICS G130 and G150 converters in constant-torque drives

as a function of the output frequency ratio in %

Figure 1b) shows the characteristic curve of the efficiency for constant-torque drives as a function of the output

current ratio IOut/IOut-rated which is proportional to the motor torque ratio M/Mrated. The parameter for the family of

curves is the output frequency ratio fOut/fOut-rated which is proportional to the motor speed ratio n/nrated.

Figure 1b)

Efficiency of SINAMICS G130 and G150 converters in constant-torque drives

as a function of the output current ratio in %

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The charts below show the partial-load efficiency of SINAMICS G130 and G150 converters for drives with quadratic

load characteristic M~n2. The calculations are based on a typical efficiency at full load of 98 %. The efficiency is

represented in three different ways. In one chart, the efficiency is shown as a function of the output frequency, in the

second chart, as a function of the output current, and in the third chart, as a function of the active output power.

Figure 2a) shows the characteristic curve of the efficiency for drives with quadratic load characteristic as a function of

the output frequency ratio fOut/fOut-rated which is proportional to the motor speed ratio n/nrated.

Figure 2a)

Efficiency of SINAMICS G130 and G150 converters in drives with quadratic load characteristic

as a function of the output frequency ratio in %

Figure 2b) shows the characteristic curve of the efficiency for drives with quadratic load characteristic as a function of

the output current ratio IOut/IOut-rated which is proportional to the motor torque ratio M/Mrated.

Figure 2b)

Efficiency of SINAMICS G130 and G150 converters in drives with quadratic load characteristic

as a function of the output current ratio in %

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Figure 2c) shows the characteristic curve of the efficiency for drives with quadratic load characteristic as a function of

the active output power ratio POut/POut-100 which is proportional to the motor power ratio P/Prated.

Figure 2c)

Efficiency of SINAMICS G130 and G150 converters in drives with quadratic load characteristic

as a function of the active output power ratio in %

1.14.2.7 Partial load efficiency of S150 converters

The charts below show the partial-load efficiency of SINAMICS S150 converters for constant-torque drives. The

calculations are based on a typical efficiency at full load of 96 %. The efficiency is represented in two different ways.

In one chart, the efficiency is shown as a function of the output frequency with the output current as a parameter, and

in the second chart, as a function of the output current with the output frequency as a parameter.

Figure 1a) shows the characteristic curve of the efficiency for constant-torque drives as a function of the output

frequency ratio fOut/fOut-rated which is proportional to the motor speed ratio n/nrated. The parameter for the family of

curves is the output current ratio IOut/IOut-rated which is proportional to the motor torque ratio M/Mrated.

Figure 1a)

Efficiency of SINAMICS S150 converters in constant-torque drives

as a function of the output frequency ratio in %

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Figure 1b) shows the characteristic curve of the efficiency for constant-torque drives as a function of the output

current ratio IOut/IOut-rated which is proportional to the motor torque ratio M/Mrated. The parameter for the family of

curves is the output frequency ratio fOut/fOut-rated which is proportional to the motor speed ratio n/nrated.

Figure 1b)

Efficiency of SINAMICS S150 converters in constant-torque drives

as a function of the output current ratio in %

The charts below show the partial-load efficiency of SINAMICS S150 converters for drives with quadratic load

characteristic M~n2. The calculations are based on a typical efficiency at full load of 96 %. The efficiency is

represented in three different ways. In one chart, the efficiency is shown as a function of the output frequency, in the

second chart, as a function of the output current, and in the third chart, as a function of the active output power.

Figure 2a) shows the characteristic curve of the efficiency for drives with quadratic load characteristic as a function of

the output frequency ratio fOut/fOut-rated which is proportional to the motor speed ratio n/nrated.

Figure 2a)

Efficiency of SINAMICS S150 converters in drives with quadratic load characteristic

as a function of the output frequency ratio in %

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Figure 2b) shows the characteristic curve of the efficiency for drives with quadratic load characteristic as a function of

the output current ratio IOut/IOut-rated which is proportional to the motor torque ratio M/Mrated.

Figure 2b)

Efficiency of SINAMICS S150 converters in drives with quadratic load characteristic

as a function of the output current ratio in %

Figure 2c) shows the characteristic curve of the efficiency for drives with quadratic load characteristic as a function of

the active output power ratio POut/POut-100 which is proportional to the motor power ratio P/Prated.

Figure 2c)

Efficiency of SINAMICS S150 converters in drives with quadratic load characteristic

as a function of the active output power ratio in %

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1.15 Parallel connections of converters

1.15.1 General

It can be useful to connect complete converters and their components (Infeed Modules and Motor Modules) in

parallel for a number of reasons:

· To increase the converter output power if it is not technically or economically feasible to achieve the

required output power by any other means. For example, it is a relatively complicated procedure to create

parallel connections of large numbers of IGBT modules within the same power unit which means that

using parallel connection of complete power unit s can be the simpler and more cost-effective solution.

· To increase the availability in cases where it is necessary after a converter malfunction to maintain

emergency operation during which the unit can operate at a lower output than its rated value. In the event

of more or less minor defects within the power unit, for example, it is feasible to deactivate the affected

power unit via the converter control system without shutting down the power unit that are still functional.

The parallel connection strategy for SINAMICS units is essentially designed to increase the converter power output.

The parallel-connected modules (Infeed Modules and Motor Modules) are driven and monitored by a single Control

Unit and are constructed of exactly the same hardware components as the equivalent modules for single drives. All

the functions required for parallel operation are stored in the firmware of the Control Unit. The use of a single shared

Control Unit for the parallel-connected modules and the fact that each fault in any module leads to immediate

shutdown of the entire paralleled system means that a converter parallel connection can be regarded in practical

terms as a single, high-power-output converter.

The parallel connection must be protected on the line side. This protection can be realized by a single circuit breaker

for the entire parallel connection or several circuit breakers or switch disconnectors with fuses or fuse holders with

fuses that are assigned to the partial infeeds of the parallel connection. In the latter case, the line-side components

specified for the relevant individual infeeds in Catalog D 21.3 should be used wherever possible. Where these

components are used to protect parallel connections, they must be monitored commonly so as to ensure reliable

detection of malfunctions of individual protective devices within the parallel connection.

1.15.2 Parallel connections of SINAMICS converters

The modular SINAMICS S120 drive system provides the option of operating Infeed Modules and Motor Modules in

parallel on S120 units in the Chassis and Cabinet Modules format. SINAMICS S120 units in Booksize and Blocksize

format cannot be operated in parallel.

S120 Motor Modules can be operated in parallel in vector control mode (drive objects of vector type), but not in servo

control mode (drive objects of servo type).

The SINAMICS G150 cabinet units in the high output range (P ≥ 630 kW for 400 V units, P ≥ 630 kW for 500 V units

and P ≥ 1000 kW for 690 V units) are also designed as a parallel connection. They are based on two low-output

G150 converter cabinets or, in the power range above 1500 KW, on the parallel connection of two Basic Line

Modules and two or three Motor Modules. The details and special features of the G150 converter parallel connections

are described at the end of chapter "Converter Cabinet Units SINAMICS G150".

This section will provide a more detailed description of the basic options for making parallel connections of units of

the SINAMICS S120 modular drive system in Chassis and Cabinet Modules format.

A SINAMICS S120 converter parallel connection consists of:

· Up to four Infeed Modules (line-side rectifiers) connected in parallel.

· Up to four Motor Modules (motor-side inverters) connected in parallel.

· A Control Unit which controls and monitors the power units connected in parallel on the line and motor

sides. In addition to the line-side and motor-side parallel connections, the Control Unit is capable of

controlling one further Motor Module or drive object of vector type.

· Components on the line and motor side for line-side protection of the parallel connection, for de-coupling the

parallel-connected power units and for ensuring symmetrical current distribution.

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The following S120 Modules can be connected in parallel:

· Basic Line Modules, 6-pulse and 12-pulse (with the relevant line reactors in each case)

· Smart Line Modules, 6-pulse and 12-pulse (with the relevant line reactors in each case)

· Active Line Modules (with the relevant Active Interface Modules in each case)

· Motor Modules in vector control mode (drive objects of vector type)

It is important to note that the parallel-connected Infeed Modules or Motor Modules, which are absolutely identical to

the corresponding modules for single drives in terms of hardware, must be of exactly the same type and for the same

rated voltage and rated output. The firmware versions and version releases of the CIM modules must also be

identical. It is therefore not permissible to mix different variants of Infeed Module within the same parallel connection

(e.g. a mixture of Basic Line Modules with Smart Line Modules or Basic Line Modules with Active Line Modules).

The diagram below shows the basic design of a SINAMICS S120 converter parallel connection.

Principle of the SINAMICS S120 converter parallel connection

As a result of unavoidable tolerances in the electrical components (e.g. diodes, thyristors and IGBTs) and imbalances

in the mechanical design of the parallel connection, symmetrical current distribution cannot be assured automatically.

The mechanical dimensions of the converters are particularly large with multiple parallel connections, resulting

inevitably in imbalances in the busbars and cabling which have a negative impact on current distribution.

There is a range of different measures which can be taken to ensure symmetrical current distribution between the

parallel-connected power units:

· Use of selected components with low forward voltage tolerances (this option is not used on SINAMICS

equipment due to a variety of disadvantages associated with it, e.g. high costs and problems with spare

parts stocking)

· Use of current-balancing system components such as line reactors or motor reactors

· Use of the most symmetrical mechanical design that is possible

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· Symmetrical power cabling at the plant side between the transformer and the parallel-connected Infeeds

and between the parallel-connected Motor Modules and the motor (use of cables of the same type with

identical cross-section and length)

· Use of an electronic current sharing control (ΔI control)

In practice, however, it is not generally possible to achieve an absolutely symmetrical current distribution, even when

several of the above measures are combined. As a result, a slight current reduction of a few per cent below the rated

current must be taken into account when parallel connections of power units are configured.

The current reduction from the rated value of the individual modules is as follows:

· 7.5 % for parallel connections of S120 Basic Line Modules and S120 Smart Line Modules because the

modules are not equipped with an electronic current sharing control

· 5.0 % for parallel connections of S120 Active Line Modules and S120 Motor Modules because the

modules are equipped with an electronic current sharing control

1.15.3 Parallel connection of S120 Basic Line Modules

Parallel connections of Basic Line Modules can be implemented as either a 6-pulse circuit if the parallel-connected

modules are connected to a two-winding transformer, or as a 12-pulse circuit if the parallel-connected modules are

connected to a three-winding transformer with secondary windings that supply voltages with a phase shift of 30 °.

6-pulse parallel connection of S120 Basic Line Modules

With the 6-pulse parallel connection, up to four Basic Line Modules are supplied by a common two-winding

transformer on the line side and controlled by a common Control Unit.

6-pulse parallel connection of S120 Basic Line Modules

As Basic Line Modules have no electronic current sharing control, the current must be balanced by the following

measures:

· Use of line reactors with a relative short-circuit voltage of vk = 2 %

· Use of symmetrical power cabling between the transformer and the parallel-connected BLMs (cables of

identical type with the same cross-section and length)

The current reduction from the rated value for individual Basic Line Modules in a parallel connection is 7.5 %.

Fundamental Principles and System Description

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12-pulse parallel connection of S120 Basic Line Modules

With 12-pulse parallel connections, up to four Basic Line Modules are supplied by a three-winding transformer on the

line side. In this case, an even number of modules, i.e. two or four, must be divided between the two secondary

windings. The Basic Line Modules of both secondary windings are controlled by a common Control Unit, despite of

the 30° phase-displacement. This is possible because the Basic Line Modules produce their gating impulses for the

thyristors, which must have a phase displacement by 30° due to the 12-pulse circuit, by independent gating units in

the individual Basic Line Module, which are not synchronized by the Control Unit.

12-pulse parallel connection of S120 Basic Line Modules

As Basic Line Modules do not have an electronic current balancing control, the three-winding transformer, the power

cabling and the line reactors as well as the supply system must meet the following requirements in order to provide

an effective balancing of currents. Furthermore, no additional loads may be connected to only one of the two low-

voltage windings as this would prevent symmetrical loading of both low-voltage windings. Furthermore, it is not

advisable to connect multiple 12-pulse Infeeds to a single three-winding transformer, particularly in systems which

feature Basic Line Modules equipped with thyristors that precharge the DC link by the phase angle control method.

Requirements of the three-winding transformer, the power cabling and the line reactors

· Three-winding transformer must be symmetrical, recommended vector groups Dy5d0 or Dy11d0.

· Relative short-circuit voltage of three-winding transformer vk ≥ 4 %.

· Difference between relative short-circuit voltages of secondary windings Δvk ≤ 5 %.

· Difference between no-load voltages of secondary windings ΔV ≤ 0.5 %.

· Use of symmetrical power cabling between the transformer and the Basic Line Modules (cables of

identical type with the same cross-section and length)

· Use of line reactors with a relative short-circuit voltage of vk = 2 %. (Line reactors can be omitted if a

double-tier transformer is used and only one BLM is connected to each secondary winding of the

transformer).

A double-tier transformer is generally the best means of meeting the relatively high requirements of the three-winding

transformer. When other types of three-winding transformer are used, it is advisable to install line reactors.

Alternative solutions for obtaining a phase displacement of 30 °, such as two separate transformers with different

vector groups, should be used only if the transformers are practically identical (excepting their different vector

groups), i. e. if both transformers are supplied by the same manufacturer.

The current reduction from the rated value for individual Basic Line Modules in a parallel connection is 7.5 %. This is

also valid for the simplest form of a 12-pulse parallel configuration, if only one Basic Line Module is connected to

each secondary transformer winding, because also in this configuration the transformer’s tolerance can lead to an

uneven current distribution.

Since the three-winding transformer possesses a star winding and a delta winding, and the delta winding has no

neutral point which could be usefully grounded, 12-pulse parallel connections of S120 Basic Line Modules are

connected to two ungrounded secondary windings and thus to an IT system. For this reason, an insulation monitor

must be provided.

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Requirements of the supply system

In addition to the requirements of the three-winding transformer, the power cabling and the line reactors, the supply

system must also meet certain standards with respect to the voltage harmonics present at the point of common

coupling of the three-winding transformer. This is because high voltage harmonics can (depending on their phase

angle relative to the fundamental wave) cause unwanted distortion of the time characteristics of the voltages of the

two low-voltage windings, potentially resulting in an extremely unbalanced current load on the transformer and the

Basic Line Modules. A pronounced 5th-order voltage harmonic can have the most critical impact, and also a strong

7th-order voltage harmonic can have certain negative effects. By contrast, higher-order voltage harmonics do not

have any significant influence. Pronounced 5th and 7th-order harmonics can be caused, for example, by high-output

6-pulse loads (DC motors, direct converters) that are supplied by the same medium-voltage system.

For this reason, the following information regarding the 5th-order voltage harmonic present at the point of common

coupling of the three-winding transformer must be taken into account.

- 5th-order voltage harmonic at the point of common coupling of the transformer ≤ 2 %:

12-pulse operation is possible. The 7.5 % current derating specified for 12-pulse operation covers all

possible current imbalances that are caused by tolerances of the transformer, the cabeling and the line

reactors as well as by the line voltage harmonics.

- 5th-order voltage harmonic at the point of common coupling of the transformer > 2 %:

12-pulse operation under supply system conditions of this kind is not easily possible due to the potential for

severe imbalances. On the one hand the 7.5 % current derating specified for 12-pulse operation is no longer

sufficient to safely prevent overloading of the transformer and the Basic Line Modules. On the other hand,

current harmonics with the harmonic number h = 5, 7, 17, 19, 29, 31, etc. cannot be suppressed as required

on the high-voltage side of the transformer when the current is very unbalanced.

If a high 5th-order harmonic > 2 % is present in the voltage at the point of common coupling of the three-winding

transformer, the following solutions can be attempted:

- Reduce the harmonic content in the supply system using a harmonic compensation system (5th-order

harmonic < 2 %) and dimension the 12-pulse parallel connection of Basic Line Modules by applying the

7.5 % current derating mentioned above

- Retain the high harmonic content in the voltage (5th-order harmonic > 2 %) and use a 12-pulse parallel

connection of Basic Line Modules subject to the following boundary conditions:

o Perform an analysis of the supply system in advance in order to identify the existing spectrum of

voltage harmonics, particularly the 5th-order harmonic

o Calculate the required and generally significantly higher current derating of up to 35 % depending

on the results of the supply system analysis and overdimension transformer and the 12-pulse

parallel connection of Basic Line Modules accordingly by up to 50 %

o Accept that the current harmonics with harmonic number h = 5, 7, 17, 19, 29, 31, etc. cannot be

fully compensated

- Use an Active Infeed with a two-winding transformer

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1.15.4 Parallel connection of S120 Smart Line Modules

Parallel connections of Smart Line Modules can be implemented as either a 6-pulse circuit if the parallel-connected

modules are connected to a two-winding transformer, or as a 12-pulse circuit if the parallel-connected modules are

connected to a three-winding transformer with secondary windings that supply voltages with a phase shift of 30 °.

6-pulse parallel connection of S120 Smart Line Modules

With the 6-pulse parallel connection, up to four Smart Line Modules are supplied by a common two-winding

transformer on the line side and controlled by a common Control Unit.

6-pulse parallel connection of S120 Smart Line Modules

As Smart Line Modules have no electronic current sharing control, the current must be balanced by the following

measures:

· Use of line reactors with a relative short-circuit voltage of vk = 4 %

· Use of symmetrical power cabling between the transformer and the Smart Line Modules (cables of

identical type with the same cross-section and length)

The current reduction from the rated value for individual Smart Line Modules in a parallel connection is 7.5 %.

12-pulse parallel connection of S120 Smart Line Modules

With 12-pulse parallel connections, up to four Smart Line Modules are supplied by a three-winding transformer on the

line side. In this case, an even number of modules, i.e. two or four, must be divided between the two secondary

windings. It is absolutely essential that the Smart Line Modules of both secondary windings are controlled by means

of two Control Units because of the phase displacement of 30º. The use of two Control Units is necessary because,

in contrast to the Basic Line Modules, the gating impulses for the IGBTs in Smart Line Modules are synchronized by

the Control Unit. Thus all Smart Line Modules controlled by one Control Unit must be connected to the same

transformer winding with equal phase position.

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12-pulse parallel connection of S120 Smart Line Modules

As Smart Line Modules do not have an electronic current balancing control, the three-winding transformer, the power

cabling and the line reactors as well as the supply system must meet the following requirements in order to provide

an effective balancing of currents. Furthermore, no additional loads may be connected to only one of the two low-

voltage windings as this would prevent symmetrical loading of both low-voltage windings. Furthermore, it is not

advisable to connect more than one 12-pulse Infeed to a three-winding transformer.

Requirements of the three-winding transformer, the power cabling and the line reactors

· Three-winding transformer must be symmetrical, recommended vector groups Dy5d0 or Dy11d0.

· Relative short-circuit voltage of three-winding transformer vk ≥ 4 %.

· Difference between relative short-circuit voltages of secondary windings Δvk ≤ 5 %.

· Difference between no-load voltages of secondary windings ΔV ≤ 0.5 %.

· Use of symmetrical power cabling between the transformer and the Smart Line Modules (cables of

identical type with the same cross-section and length)

· Use of line reactors with a relative short-circuit voltage of vk = 4 %.

A double-tier transformer is generally the best means of meeting the relatively high requirements of the three-winding

transformer. Alternative solutions for obtaining a phase displacement of 30 °, such as two separate transformers with

different vector groups, should be used only if the transformers are practically identical (excepting their different

vector groups), i. e. if both transformers are supplied by the same manufacturer.

The current reduction from the rated value for individual Smart Line Modules in a parallel connection is 7.5 %. This is

also valid for the simplest form of a 12-pulse parallel configuration, if only one Smart Line Module is connected to

each secondary transformer winding, because also in this configuration the transformer’s tolerance can lead to an

uneven current distribution.

Since the three-winding transformer possesses a star winding and a delta winding, and the delta winding has no

neutral point which could be usefully grounded, 12-pulse parallel connections of S120 Basic Line Modules are

connected to two ungrounded secondary windings and thus to an IT system. For this reason, an insulation monitor

must be provided.

Due to the phase displacement of 30º between both secondary winding systems and the control of both systems by

separate Control Units, it is generally not possible to ensure, that both systems contribute equally to the precharging

of the connected DC link. In order to safely ensure that the individual subsystems are not overloaded during

precharging, the 12-pulse parallel connection of Smart Line Modules should be dimensioned such that each

subsystem is able to precharge the entire DC link on its own.

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Requirements of the supply system

In addition to the requirements of the three-winding transformer, the power cabling and the line reactors, the supply

system must also meet certain standards with respect to the voltage harmonics present at the point of common

coupling of the three-winding transformer. This is because high voltage harmonics can (depending on their phase

angle relative to the fundamental wave) cause unwanted distortion of the time characteristics of the voltages of the

two low-voltage windings, potentially resulting in an extremely unbalanced current load on the transformer and the

Smart Line Modules. A pronounced 5th-order voltage harmonic can have the most critical impact, and also a strong