Ground Fault Rela
y
s
The GFR 4000 ground fault relay is specifically
designed to provide complete motor pro t ection
without the problems associated with high sen sitivity
nuisance tripping. The GFR 4000 is unique because
it has predictive as well as protective capabilities.
The unit operates continuously in one of two mode s,
either on-line or off-line. The GFR4000 has metering
output signals for use with a remote meter or PLC so
that ground faults may be detected at an early stage.
The GFR 4000 operates on grounded, high
resistance grounded and unground ed systems. The
unit can be directly connected to supplies up to
1300V, 1PH or 3 PH, 50-60 HZ. For supplie s from
1300 V to 5000 V, the GFR 4000 must be connected
to the HTC 5000 high tension coupling unit.
Operation
On-Line Mode Under normal running conditions the
GFR 4000 operates as a sensitive ground fault relay
working in conjunction with a separately connected
core palance current transformer. The alarm range
is adjustable with a 10 position range of fixed
operating points between 10 mA and 3A. Time delay
is adjustable between 0 and 1 seconds. When the
preset response value is exceeded, the GFR4000
operates the output relay after the preset time delay.
There is instant LED indication. The unit can be set
for Active or Failsafe mode and ha s memory and
auto reset facilities. The GFR 4000 also monitors
the loop connection to the current transformer and
provides LED indication should it detect a C.T. fault.
The metering output signal is prop ortional to the
actual leakage current and is expressed as a
percentage of the GFR 4000 leakage current setting.
The output is 0 – 1mA FSD with the meter reading
scaled 0 to 100% relating directly to the selected
current trip value.
Features/Benefits
Adjustable sensitivity from 10 mA t to 3.0 A to
reduce nuisance trips.
Precise insulation resistance readings indicate
problems in advance
Adjustable time delay adapts to unique
applications.
Fail-safe operation
On Line monitoring of ground to detect any change
in leakage current
Off line monitoring of insulation resistance to notify
or halt unacceptable levels
C.T. Loop Monitoring
Test/Reset buttons to assure operation
NO/NC form “C” output alarm relay contacts
GFR4000 Continuous On and Off-Line Monitor
Off-Line Mode The GFR4000 automatically changes
state by means of a small auxiliary contact on the main
contactor when the motor (or load) is switched off. The
unit becomes a high performance insulation resi stance
monitor. It imposes a small DC current onto the
network which travels through the motor windings an d
interconnecting cable from the motor starter. A green
LED indicates that the off-line monitoring function is
active. The insulation resistan ce function of the GFR
has an adjustable alarm range from 250 kΩ – 2 MΩ.
The red LED indicates “low resi stance” and operate s
instantly when the trip relay is activated. The off-line
feature also has an Active/Failsafe M ode and
Memory/Auto Reset facilities. The metering output is 0-
1mA FSD and relates to an insulation range of 0 to
infinity.
WKE Series Current Transformer
The WKE series C.T.s are specifically designed to
operate with POWR-GARD relay s. These C.T.s are
protected from open circuit burnout an d will saturate at
low voltages to prevent damage to the C.T. There are
varying diameters of C.T. s ranging from 1” to 8 ¼ “.
The C.T. is connected across terminals 16 and 17. It is
essential when installing C.T.s that only the load cable
conductors L and N (1 PH) or L1, L2, and L3 with N (3
ph or 3 or 4 wire), are passed through the center of the
C.T. The ground wire must remain out side the C.T.
core.
Littelfuse, Inc. POWR-GARD Produ cts
800 E. Northwest Highway, Des Plaines, IL 60016 1-800-TEC-FUSE | www.littelfuse.com
Ground Fault Rela
y
s
Specifications
Nominal AC Insulation Voltag e 660 V AC
Insulation Ground to UL 1053
IEC1010 and VDE 0110 Class C
Test Voltage 1000 V AC
Operation Class Continuous
Supply voltage Vs 24/115 V ac 50-60 Hz
Power Input 5 V A
Alarm Relay Contacts 2 volt-free NO/NC
Switching capacity 1200VA
Rated Contact voltage 250V
Continuous Current 5 A
Breaking Capacity
@240V AC P.F. = 0.4 3 A
@ 110VDC, @L/R = 0 0.3 A
Relay Function Selection by linked terminals
Adjustable Function Failsafe/Active
Relay Alarm Memory Hand/Auto Reset
Factory Settings Failsafe/Hand
Operating Ambient Temp. -10 to +60 deg. C
Storage Ambient Temp. -40 to +80 dec. C
Mounting
Terminal Screws M2.5
Terminal Capacity 0.5 to 2.5 mm⒉
Weight 12 oz
Enclosure 3 15/16”W x 2 15/16 H
x4 3/8” D
On-Line Current Relay 10/30/60/80/100/
Response Range 300/800mA, 1/3 A
4 step time delay 0 /.25/.5 / 1 sec.
Metering driver 0 – 1mA FSD
1 volt-free NO/NC contact
Off-Line Monitor Max
Voltage for :
Direct Connection 1300V
With HTC 5000 5000V
Measuring Voltage 12 V DC
Measuring Current 20 uA
DC Internal Resistance 600 KΩ
AC impedance at 50-60 Hz >1MΩ
Response adjustment pot 250kΩ – 2MΩ
Response delay <250mSec
Max leakage capacitance to < 1 uF
ground
Max . Stray DC voltage 1000V DC
permissible
K.Ω Meter Driver 0 – 1mA FSD
Alarm Relay Contacts 1 volt-free NO/NC
Contact
Current Transformer
C.T. Type WKE
Burden in GFR4000 ac impedance, 50-60 Hz
150Ω- 1 KΩ
Supply Voltage and Test
The GFR4000 will operate on supply volta ges of 115 V
ac or 24V ac, 50-60 Hz(+/- 15%). The green “ON” LED
indicates power present. The Test button will test both
leakage current and insulation resistance regardless of
operation mode. Depress test button for at least 5 secs.
to complete test. All LEDs will operate and relay
contacts will change to fault/alarm position. If the relay is
set to memorize faults, these will remain. Allow 5
seconds before operating the Reset pushbutton.
External test/reset facilities via S6/S7 as shown in the
Connection Diagram.
Warning!
Before carrying out Megger test or v oltage
pressure test on the system, be sure to
disconnect the GFR4000.
It is essential that the co nnection to ground
from terminal 30 is securely connected.
When commissioning the installation, always
check the relay performance by using a real
fault to ground (a 10kΩ resistor rate d at 20
watts in a 3ph 660V network will produce
approximately 40mA of leakage current and
indicate a 10kΩ fault).
Littelfuse, Inc. POWR-GARD Produ cts
800 E. Northwest Highway, Des Plaines, IL 60016 1-800-TEC-FUSE | www.littelfuse.com
Ground Fault Rela
y
s
Legend
H1 LED green power “ON”
H2 LED red leakage current “GROUND FAULT”
H3 LED red open C.T. Circuit “FAULT”
H4 LED green insulation resistance monitor “ACTIVE”
H5 LED red low insulation “FAULT”
S1 Test button for general test
S3 Leakage current response selector switch
S4 Leakage current response time delay
S5 Pushbutton “RESET”
S6 External test button (not included)
S7 External reset button (not included)
R1 Insulation resistance response potentiometer
K1 Insulation resistance alarm relay
K2 Leakage current alarm relay
I External meter for leakage current (not included)
R External meter for insulation resistance
(not included)
C.T. Current transformer WKE
HTC High Tension coupler for connections above
1300V ac
Terminals
2 Coupling for insulation resi stance monitoring mode
5 – 6 115 V ac power supply (+/- 15%)
5 – 7 24 V ac power supply (+/- 15%)
10-11-12 Contact relay K1
13-14-15 Contact relay K2
16 – 17 C.T. connection
18 – 19 Link for auto reset K2
19 – 20 Link for active mode K2
21 – 22 Link for auto reset K1
22 – 23 Link for active mode K1
24 – 25 Leakage current meter
25 – 26 Insulation resistance meter
27 – 28 Link for active mode for insulation
resistance monitor
29 Coupling for HT C 5000/8000
30 Measuring ground
** All external switches are sh own as optional
NOTE:
Electronic terminals (16 – 30) are potential free.
Terminal 30 and Terminal E must be connected to ground !
Littelfuse, Inc. POWR-GARD Produ cts
800 E. Northwest Highway, Des Plaines, IL 60016 1-800-TEC-FUSE | www.littelfuse.com
Ground Fault Rela
y
s
Littelfuse, Inc. POWR-GARD Produ cts
800 E. Northwest Highway, Des Plaines, IL 60016 1-800-TEC-FUSE | www.littelfuse.com
WKE Series Current Transformers
The WKE Series of current transformers is a
key component of the POWR-GARD ground
fault detection product line. These CTs are
highly accurate. They convert very small
differential currents to an ac voltage and output
this signal to the connected POWR-GARD
ground fault relay. The WKE Series CTs are
made from high-density mu metal which has
unique and repeatable output characteristics.
Features
The WKE CTs have built-in safety features far
surpassing those of CTs with a ferrite core.
The WKE CT is resistant to open circuit burn
out and will saturate at safe, low-level voltages.
The CTs are housed with an insulating
protection. They have built in brackets to
facilitate mounting. Terminal cover may be
wire sealed for further protection
Primary Current 2500A
Secondary Current 350mA
NSV 600Vac
BIL Rating 2000V
Rated Frequency 10 – 1000Hz
Thermal current rating 70˚ C
No Fixed Burden
Accuracy 99%
Flux Shielding
Installation Instructions
When installing the WKE CTs, ensure the
following:
1. Only the load carrying conductors pass
through the center of the CT. (This
means L1 + N for 1 phase and L1+ L2 +
L3 for 3 phases.)
2. The power conductors pass through the
center of the CT and are preferably
bound together to keep the conductors
uniformly spaced.
3. The power conductors pass
PERPENDICULAR to the CT and,
whenever practical, continue
perpendicular to the CT on both sides of
the CT for 3”.
4. The power conductors should not be
installed in a way that allows them to run
along the side edges of the CT.
5. Whenever practical, locate the CT away
from noise-generating devices such as
transformers, frequency converters, etc.
Dimensions (in)
a b c d e
WKE 25 1 3 3.9 1.63 3.63
WKE 60 2.36 3.9 5.25 2.37 4.50
3.74
WKE 95 5.5 6.9 3.25 6.25
WKE130 5.12 7.25 8.5 4 7.0
WKE 200 8.0 10.4 12.1 6.0 11.4
