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RU Relays & Sockets
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RU Series Universal Relays
Key features:
• Full featured universal miniature relays
• Designed with environment taken into consideration
• Two terminal styles: plug-in and PCB mount
• Non-polarized LED indicator
• No internal wires, lead-free construction
• Cadmium-free contacts
• Mechanical flag indicator
• Manual latching lever with color coding for AC or DC coil
• Snap-on yellow marking plate; optional marking plates are available in four other colors
• Maximum contact ratings: 10A (RU2), 6A (RU4), 3A (RU42)
• UL Recognized, CSA Certified, EN Compliant

EN61810-1
With Latching or Momentary Lever
Mechanical Indicator*
The contact position can be confirmed through
the five small windows.
Marking Plate
Standard yellow marking plate is easily replaced
with optional marking plates in four colors for
easy identification of relays.
LED Indicator*
Non-polarized green LED indicator is standard
provision for plug-in terminal, latching lever
types
Latching and Momentary Lever
Using the lever, operation can be checked without energiz-
ing the coil. The lever is color coded for AC and DC coils.
Latching Momentary
AC coil: Orange Red
DC coil: Green Blue
Note: Turn off the power to the relay coil when using the latching
lever. After checking the operation, return the latching lever
in the normal position.
In Normal Operation
Standard (without lever)
Coil Voltage Tape Color
24V AC White
100 to 110V AC Clear
110 to 120V AC Blue
200 to 220V AC Black
220 to 240V AC Red
24V DC Green
6V DC
Voltage marking on
yellow tape
12V DC
48V DC
110V DC
AC/DC Color Marking
For identification of AC or DC coils.
AC coil: Yellow
DC coil: Blue
Mechanical Indicator*
Marking Plate
LED Indicator*
Non-polarized green LED indicator is standard
provision for plug-in terminal types.
AC Coil DC Coil
*Not available on PCB type.
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Relays & Sockets
Part Number Selection
Part Number
Contact Model Standard With Latching Lever With Momentary Lever Coil Voltage Code
(Standard Stock in bold)
DPDT (10A) Standard RU2S-C-0RU2S-0RU2S-M-0A24, A110, A220
D6, D12, D24, D48, D110
With RC (AC coil only) RU2S-CR-0RU2S-R-0RU2S-MR-0A110, A220
With diode (DC coil only) RU2S-CD-0RU2S-D-0RU2S-MD-0D6, D12, D24, D48, D110
PCB RU2V-NF-0 — —A24, A110, A220
D6, D12, D24, D48, D110
4PDT (6A) Standard RU4S-C-0RU4S-0RU4S-M-0A24, A110, A220
D6, D12, D24, D48, D110
With RC (AC coil only) RU4S-CR-0RU4S-R-0RU4S-MR-0A110, A220
With diode (DC coil only) RU4S-CD-0RU4S-D-0RU4S-MD-0D6, D12, D24, D48, D110
PCB RU4V-NF-0— — A24, A110, A220
D6, D12, D24, D48, D110
4PDT Bifurcated (3A) Standard RU42S-C-0RU42S-0RU42S-M-0A24, A110, A220
D6, D12, D24, D48, D110
With RC (AC coil only) RU42S-CR-0RU42S-R-0RU42S-MR-0A110, A220
With diode (DC coil only) RU42S-CD-0RU42S-D-0RU42S-MD-0D6, D12, D24, D48, D110
PCB RU42V-NF-0— — A24, A110, A220
D6, D12, D24, D48, D110
1. Plug-in terminal models have an LED indicator and a mechanical indicator as standard.
2. PCB models do not have an LED indicator or a mechanical indicator. Ordering Information
When ordering, specify the Part No. and coil voltage code:
(example) RU2S-C A110
Part No. Coil Voltage Code
Coil Voltage Table
Coil Voltage Code A24 A110 A220 D6 D12 D24 D48 D110
Coil Rating 24V AC 110-120V AC 220-240V AC 6V DC 12V DC 24V DC 48V DC 110V DC
Sockets
Relays Spring Clamp
DIN Rail Mount
Standard DIN
Rail Mount
Finger-safe DIN
Rail Mount Panel Mount PCB Mount
RU2S (DPDT) SU2S-11L SM2S-05 SM2S-05C
SY4S-51
SM2S-61
SM2S-62
RU4S (4PDT)
RU42S (4PDT) SU4S-11L SY4S-05 SY4S-05C SY4S-61
SY4S-62
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Hold Down Springs & Clips
Appearance Item Relay For DIN
Mount Socket
For Through
Panel & PCB
Mount Socket
Pullover Wire
Spring
RU2S/RU4S/
RU42S SY4S-02F1 SY4S-51F1
Note: Order 2 pieces for each relay
Leaf Spring
(side latch)
RU2S/RU4S/
RU42S SFA-202* SFA-302*
Leaf Spring
(top latch)
RU2S/RU4S/
RU42S SFA-101* SFA-301*
Accessories
Name Part Number Color Code *
Marking Plate RU9Z-P* A (orange), G (green), S (blue), W (white), Y (yellow)
Specify a color code when ordering. The marking plate can be removed from the relay by inserting
a flat screwdriver under the marking plate.
Specifications
Model (Contact) RU2 (DPDT) RU4 (4PDT) RU42 (4PDT-bifurcated)
Contact Material Silver alloy Silver (gold clad) Silver-nickel (gold clad)
Contact Resistance 150 mΩ maximum
Minimum
Applicable Load 2
24V DC, 5 mA
(reference value) 1V DC, 1 mA 1V DC, 0.1 mA
Operating Time 320 ms maximum
Release Time 320 ms maximum
Power Consumption AC: 1.1 to 1.4VA (50 Hz), 0.9 to 1.2VA (60 Hz) DC: 0.9 to 1.0W
Insulation Resistance 100MΩ minimum (500V DC megger)
Dielectric Strength
Between contact and coil: 2500V AC, 1 minute
Between contacts of different poles:
2500V AC, 1 minute 2000V AC, 1 minute
Between contacts of the same pole: 1000V AC, 1 minute
Operating Frequency Electrical: 1800 operations/h maximum
Mechanical: 18,000 operations/h maximum
Vibration Resistance Damage limits: 10 to 55 Hz, amplitude 0.5 mm
Operating extremes: 10 to 55 Hz, amplitude 0.5 mm
Shock Resistance Damage limits: 1000 m/s2 (100G)
Operating extremes: 150 m/s2 (15G)
Mechanical Life AC: 50,000,000 operations
DC: 100,000,000 operations 50,000,000 operations
Electrical Life 4See table on page 794
Operating
Temperature 5
PCB model: –55 to +70°C (no freezing)
Blade model: –55 to +60°C (no freezing)
Operating Humidity 5 to 85% RH (no condensation)
Weight Approx. 35g
1. Measured using 5V DC, 1A voltage drop method
2. Measured at operating frequency of 120 operations/min (failure rate level P, reference value)
3. Measured at the rated voltage (at 20°C), excluding contact bouncing;
Release time of AC relays with RC: 25 ms maximum
Release time of DC relays with diode: 40 ms maximum
4. Contact Load and Electrical Life (at ambient temperature 20°C)
5. Measured at the rated voltage.
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Relays & Sockets
Accessories
Item Appearance Use with Part No. Remarks
Aluminum
DIN Rail
(1 meter length)
All DIN rail sockets BNDN1000
The BNDN1000 is designed to accommodate DIN mount sockets.
Made of durable extruded aluminum, the BNDN1000 measures 0.413
(10.5mm) in height and 1.37 (35mm) in width (DIN standard). Standard
length is 39” (1,000mm).
DIN Rail End
Stop DIN rail BNL5 9.1 mm wide.
Replacement
Hold-Down
Spring Anchor
Horseshoe clip for DIN rail
sockets Y778-011 For use on DIN rail mount socket when using pullover wire hold down
spring. 2 pieces included with each socket.
Coil Ratings
Rated Voltage (V)
Coil
Voltage
Code
Rated Current (mA)
±15% (at 20°C) Coil Resistance (Ω)
±10% (at 20°C)
Operating Characteristics (values at 20°C)
50 Hz 60 Hz Maximum Continuous
Applied Voltage Pickup Voltage Dropout Voltage
AC
(50/60 Hz)
24 A24 49.3 42.5 164
110% 80% maximum 30% minimum110-120 A110 8.4-10.0 7.1-8.2 4,550
220-240 A220 4.2-5.0 3.6-4.2 18,230
DC
6 D6 155 40
110% 80% maximum 10% minimum
12 D12 80 160
24 D24 44.7 605
48 D48 18 2,560
110 D110 8.9 12,100
1. The rated current includes the current of the LED indicator.
Surge Suppressor Ratings
Model Ratings
AC Coil With RC RC series circuit
R: 20 kΩ, C: 0.033 µF
DC Coil With Diode Diode reverse voltage: 1000V
Diode forward current: 1A
Contact Ratings
Maximum Contact Capacity
Contact Continuous
Current
Allowable Contact Power Voltage
(V)
Rated Load
Resistive Load Inductive Load Res. Load Ind. Load
DPDT 10A 2500VA AC 1250VA AC 250 AC 10A 5A
300W DC 150W DC 30 DC 10A 5A
4PDT 6A 1500VA AC 600VA AC 250 AC 6A 0.8A
180W DC 90W DC 30 DC 6A 1.5A
4PDT
bifurcated 3A 750VA AC 200VA AC 250 AC 3A 0.8A
90W DC 45W DC 30 DC 3A 1.5A
1. On 4PDT relays, the maximum allowable total current of neighboring two poles is 6A. At the rated
load, make sure that the total current of neighboring two poles does not exceed 6A (3A + 3A = 6A).
2. Inductive load for the rated load — cos ø = 0.3, L/R = 7 ms
UL and c-UL Ratings
Voltage Resistive General Use Horse Power Rating
RU2 RU4 RU42 RU2 RU4 RU42 RU2 RU4 RU42
250V AC 10A — 3A — 6A — — 1/10HP —
30V DC 10A 6A 3A — — — — — —
CSA Ratings
Voltage Resistive
RU42
250V AC 3A
30V DC 3A
TÜV Ratings
Voltage Resistive Inductive
RU2 RU4 RU42 RU2 RU4 RU42
250V AC 10A 6A 3A 5A 0.8A 0.8A
30V DC 10A 6A 3A 5A 1.5A 1.5A
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Socket Specifications
Sockets Terminal Electrical Rating Wire Size Torque
DIN Rail Mount
Sockets
SU2S-11L Spring clamp terminals 250V/10A 24-16 AWG —
SU4S-11L Spring clamp terminals 250V/6A (using RU4), 10A (using RU2) 24-16 AWG —
SM2S-05 M3 screw with captive wire clamp 300V, 10A Maximum up to 2–#14AWG 5.5-9in•lbs
SM2S-05C M3 screw with captive wire clamp, fingersafe 300V, 10A Maximum up to 2–#14AWG 5.5-9in•lbs
SY4S-05 M3 screw with captive wire clamp 300V, 7A (using RU4), 10A (using RU2) Maximum up to 2–#14AWG 5.5-9in•lbs
SY4S-05C M3 screw with captive wire clamp, fingersafe 300V, 7A (using RU4), 10A (using RU2) Maximum up to 2–#14AWG 5.5-9in•lbs
Through Panel
Mount Socket SY4S-51 Solder 300V, 7A — —
PCB Mount Socket SY4S-61 PCB mount 300V, 7A — —
SY4S-62 PCB mount 250V, 7A — —
Electrical Life Curves
RU2 (Resistive Load) RU4 (Resistive Load) RU42 (Resistive Load)
10
1000
100
1
10 5 10.50.1
110V DC
30V DC
250V AC
Load Current (A)
(¥ 10,000 operations)
6 3 10.50.1
10
1000
100
1
110V DC
30V DC
250V AC
Load Current (A)
(¥ 10,000 operations)
10
100
1
0.02 6310.50.1
110V DC
30V DC
250V AC
Load Current (A)
(¥ 10,000 operations)
RU2 (Inductive Load) RU4 (Inductive Load) RU42 (Inductive Load)
0.1 0.5 1 5 10
1
100
1000
10
110V DC
250V AC/30V DC
Load Current (A)
(¥ 10,000 operations)
DC: L/R = 7 ms
AC: cos ø = 0.3
1
100
10
0.1 0.50.02
Load Current (A)
(¥ 10,000 operations)
DC: L/R = 7 ms
AC: cos ø = 0.3
110V DC
30V DC
250V AC
1
100
10
0.1 0.50.02
Load Current (A)
(¥ 10,000 operations)
DC: L/R = 7 ms
AC: cos ø = 0.3
110V DC
30V DC
250V AC
Maximum Switching Current
RU2 RU4 RU42 (Bifurcated)
10
5
0.1
1
10 30 100 250 500
AC resistive
AC inductive
(cos ø = 0.3)
Load Voltage (V)
Load Current (A)
DC resistive
DC inductive
L/R = 7 ms
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Relays & Sockets
Ambient Temperature vs. Temperature Rise Curves
RU2 (AC Coil, 50 Hz) RU2 (AC Coil, 60 Hz) RU2 (DC Coil)
120
110
100
90
80
70
60
50
40
30
20
10
706050403020100
Ambient Temperature (C)
Temperature Rise (C)
Load current
5A ¥ 2 poles
Load current
10A ¥ 2 poles
No load current
010203040506
07
0
10
20
30
40
50
60
70
80
90
100
110
120
Ambient Temperature (C)
Temperature Rise (C)
Load current
5A ¥ 2 poles
Load current
10A ¥ 2 poles
No load current
010203040506
07
0
10
20
30
40
50
60
70
80
90
100
110
120
Ambient Temperature (C)
Temperature Rise (C)
Load current
5A ¥ 2 poles
Load current
10A ¥ 2 poles
No load current
RU4/RU42 (AC Coil, 50 Hz) RU4/RU42 (AC Coil, 60 Hz) RU4/RU42 (DC Coil)
010203040506
0
10
20
30
40
50
60
70
80
90
100
110
Ambient Temperature (C)
Temperature Rise (C)
Load current
3A ¥ 4 poles
Load current
6A ¥ 2 poles
No load current
120
110
100
90
80
70
60
50
40
30
20
10
706050403020100
Ambient Temperature (C)
Temperature Rise (C)
Load current
3A ¥ 4 poles
Load current
6A ¥ 2 poles
No load current
120
110
100
90
80
70
60
50
40
30
20
10
706050403020100
Ambient Temperature (C)
Temperature Rise (C)
Load current
3A ¥ 4 poles
Load current
6A ¥ 2 poles
No load current
The above temperature rise curves show the characteristics when 100% the rated coil voltage is applied.
The heat resistance of the coil is 120°C. The slant dashed line indicates the allowable temperature rise for the coil at different ambient temperatures.
Load current 6A x 2 poles is for the RU4 models only.
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Internal Connection (View from Bottom)
RU2S-* Standard RU2S-*R with RC RU2S-*D With Diode RU2V-NF-*
(14)A2
(13)A1
(12)41(9)11
(8)44(5)14
(4)42(1)12
Over 24V AC/DC coil
24V AC/DC coil or less
(13)A1 (14)A2
(1)12 (4)42
(5)14 (8)44
(9)11 (12)41
(1)12 (4)42
(5)14 (8)44
(9)11 (12)41
(13)A1 (14)A2
Over 24V DC coil
24V DC coil or less
(14)A2
(13)A1
(12)41(9)11
(8)44(5)14
(4)42(1)12
RU4S-*/RU42S-* Standard RU4S-*R/RU42S-*R With RC RU4S-*D/RU42S-*D With Diode RU4V-NF-*/RU42V-NF-*
(1)12 (2)22 (3)32 (4)42
(5)14 (6)24 (7)34 (8)44
(9)11 (10)21 (11)31 (12)41
(13)A1 (14)A2
Over 24V AC/DC coil
(14)A2
(13)A1
(12)41(11)31(10)21(9)11
(8)44(7)34(6)24(5)14
(4)42(3)32(2)22(1)12
24V AC/DC coil or less
(14)A2
(13)A1
(12)41(11)31(10)21(9)11
(8)44(7)34(6)24(5)14
(4)42(3)32(2)22(1)12
Over 24V DC coil
(14)A2
(13)A1
(12)41(11)31(10)21(9)11
(8)44(7)34(6)24(5)14
(4)42(3)32(2)22(1)12
24V DC coil or less
(14)A2
(1)12 (2)22 (3)32 (4)42
(5)14 (6)24 (7)34 (8)44
(9)11 (10)21 (11)31 (12)41
(13)A1 (14)A2
(13)A1
(12)41(11)31(10)21(9)11
(8)44(7)34(6)24(5)14
(4)42(3)32(2)22(1)12
Dimensions (mm)
RU2S RU2V
Latching
Lever
AC: Orange
DC: Green
Marking Plate (yellow)
ø1.2 ¥ 2.2 Hole
LED Indicator
(green)
35.06.4
2.6
0.5
27.5
21.0
14
58
912
13 14
Marking Plate
Removal Slot
Mechanical Indicator Window
8-ø1 Holes
27.5
12.74.1
6.4
7.0
13.2
0.8
13.2
2.6
4.0
0.5
21.0
0.5
35.0
Mounting Hole Layout
Marking Plate (yellow)
Marking Plate
Removal Slot
Color Marking
A
C: Yellow
DC: Blue
All dimensions in mm.
Marking plate removal slot is provided only on one side.
Insert a flat screwdriver into the slot to remove the marking
plate.
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Relays & Sockets
Dimensions con’t (mm)
RU4S/RU42S RU4V/RU42V
1413
1211109
8
765
4321
6.4
21.0
27.5
0.5 2.6
35.0
Latching
Lever
AC: Orange
DC: Green
ø1.2 × 2.2 Hole
LED Indicator
(green)
Marking Plate
Removal Slot
Mechanical Indicator Window
Marking Plate (yellow)
3-4.4
0.8
2.6
4.0
0.5
0.5
27.5
21.0
13.2
7.0
6.4
4.1 12.7
4.4 35.0
14-ø1 Holes
Mounting Hole Layout
Marking Plate (yellow)
Marking Plate
Removal Slot
Color Marking
A
C: Yellow
DC: Blue
All dimensions in mm.
Marking plate removal slot is provided only on one side.
Insert a flat screwdriver into the slot to remove the marking
plate.
Spring Clamp DIN Rail Mount Sockets
SU2S-11L SU4S-11L
14 13
14
8 5
912
Terminal Arrangement
38.3
37.5
32
2-ø3.2
Mounting Holes
24.0
28.8
4.4
31
80
Ring terminals
cannot be used. (Top View)
12 11 10 9
5678
4321
1314
Terminal Arrangement
38.3
37.5
32
2-ø3.2
Mounting Holes
24.0
28.8
4.4
31
80
(Top View)
Ring terminals
cannot be used.
Standard DIN Rail Mount Sockets
SM2S-05 SY4S-05
6
30
26
4.2
623 0.7
M3 Terminal
Screw
18.5
25
45
18
31.5
DIN Rail
(BNDN)
1
4
13
9
14
12
5
8
Terminal Arrangement
26
2-ø4.2 Mounting Holes
(or M4 Tapped Holes)
5.9 max.
4 max. 4.8 min.
ø3.2 min.
(Top View)
6
30
26
4.2
623 0.7
M3 Terminal
Screw
18.5
25
45
18
31.5
DIN Rail
(BNDN)
1
13
9
14
12 11 10
56
78
432
Terminal Arrangement
26
2-ø4.2 Mounting Holes
(or M4 Tapped Holes)
5.9 max.
4 max. 4.8 min.
ø3.2 min.
(Top View)
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Dimensions con’t (mm)
Finger-safe DIN Rail Mount Sockets
SM2S-05C SY4S-05C
ø5.5
25
18
2
30
6
64
26
46
1.6
4.2
29
18.2
M3 Terminal
Screw
1
4
13
9
14
12
5
8
Terminal Arrangement
35.5
26
2-ø4.2 Mounting Holes
(or M4 Tapped Holes)
DIN Rail
(BNDN)
Ring terminals
cannot be used. (Top View)
ø5.5
18
25
2
30
6
64
26
46
1.6
4.2
29
18.2
26
M3 Terminal
Screw
1
13
9
14
12 11 10
56
78
432
Terminal Arrangement
35.5
2-ø4.2 Mounting Holes
(or M4 Tapped Holes)
DIN Rail
(BNDN)
(Top View)
Ring terminals
cannot be used.
PCB Mount Sockets
SM2S-61 SM2S-62
3
11
15
27
31
0.3
25.4
21.2
1.5
13 14
1
5
912
8
4
Terminal Arrangement
* 19.2 min. when using
hold-down springs
13.2 13.8 min.
9
9-ø2 holes
(Tolerance 0.1)
14.2 min.* 16.8
4.1
10.4
1.4
(Bottom View)
(Tolerance 0.1)
13 14
1
5
912
8
4
Terminal Arrangement
1.5
13.2
8.2 min.**
3
11
15
21.2
29
0.3
9
9-ø2 holes
4.1
10.4
16.8
1.4
12.2 min.*
17.2 min. when using a hold-down spring.
13.2 min. when using a hold-down spring for
the relay with check button.
*
**
(Bottom View)
SY4S-61 SY4S-62
27
31
21.2
3
11
15
0.3
25.4
1.5
10
7
13 14
1
5
9
3
12
8
4
6
2
11
Terminal Arrangement
* 19.2 min. when using
hold-down springs
(Bottom View)
4.4
13.8 min.
9
15-ø2 holes
(Tolerance 0.1)
14.2 min.* 16.8
4.1
10.4
8.8
13.2
1.4
1.5
3
11
15
21.2
29
0.3
4.1
10.4
16.8
1.4
12.2 min.*
(Tolerance 0.1)
13.2
8.2 min.**
4.4
8.8
15-ø2 holes
9
10
7
13 14
1
5
9
3
12
8
4
6
2
11
Terminal Arrangement
13.2 min. when using a hold-down spring for
the relay with check button
17.2 min. when using a hold-down spring.
*
* *
(Bottom View)
Through Panel Mount Socket
SY4S-51
27
31
2.4
21.2
3
11
18.7
25.4
Panel Thickness:
1 to 2
10
7
13 14
1
5
9
3
12
8
4
6
2
11
Terminal Arrangement
25.6
0
+0.5
+0.2
0
* 10.4 min. when using hold-down springs
[27 (N–1) + 21.4]
5.4 min.*
N: No. of sockets mounted
0.3
(Bottom View)
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Operating Instructions
Relays & Sockets
Operating Instructions
Driving Circuit for Relays
1. To ensure correct relay operation, apply rated voltage to the relay coil.
2. Input voltage for the DC coil:
A complete DC voltage is best for the coil power to make sure of stable relay
operation. When using a power supply containing a ripple voltage, suppress
the ripple factor within 5%. When power is supplied through a rectification
circuit, the relay operating characteristics, such as pickup voltage and dropout
voltage, depend on the ripple factor. Connect a smoothing capacitor for better
operating characteristics as shown below.
+
–R
Smoothing
Capacitor
Relay
Pulsation
Emin Emax Emean
DC
Ripple Factor (%
)¥
100%
Emax –
Emin
Emax = Maximum of pulsating current
Emin = Minimum of pulsating current
Emean = DC mean value
Emean
3. Leakage current while relay is off:
When driving an element at the same time as the relay operation, special
consideration is needed for the circuit design. As shown in the incorrect
circuit below, leakage current (Io) flows through the relay coil while the relay
is off. Leakage current causes coil release failure or adversely affects the
vibration resistance and shock resistance. Design a circuit as shown in the
correct example.
Incorrect Correct
R
Io
TE
R
4. Surge suppression for transistor driving circuits:
When the relay coil is turned off, a high-voltage pulse is generated, causing a
transistor to deteriorate and sometimes to break. Be sure to connect a diode
to suppress the back electromotive force. Then, the coil release time becomes
slightly longer. To shorten the coil release time, connect a Zener diode
between the collector and emitter of the transistor. Select a Zener diode with
a Zener voltage slightly higher than the power voltage.
R
Back emf
suppressing diode
Relay
+
–
Protection for Relay Contacts
1. The contact ratings show maximum values. Make sure that these values are
not exceeded. When an inrush current flows through the load, the contact
may become welded. If this is the case, connect a contact protection circuit,
such as a current limiting resistor.
2. Contact protection circuit:
When switching an inductive load, arcing causes carbides to form on the
contacts, resulting in increased contact resistance. In consideration of contact
reliability, contact life, and noise suppression, use of a surge absorbing circuit
is recommended. Note that the release time of the load becomes slightly
longer. Check the operation using the actual load. Incorrect use of a contact
protection circuit will adversely affect switching characteristics. Four typical
examples of contact protection circuits are shown in the following table:
RC
Power CR Ind. Load
This protection circuit can be used when the load
impedance is smaller than the RC impedance in an
AC load power circuit.
•R: Resistor of approximately the same resistance
value as the load
•C:0.1 to 1 µF
This protection circuit can be used for both AC and
DC load power circuits.
R: Resistor of approximately the same resistance
value as the load
C: 0.1 to 1 µF
Diode
+
–
D
Power Ind. Load
This protection circuit can be used for DC load power
circuits. Use a diode with the following ratings.
Reverse withstand voltage: Power voltage of the
load circuit x 10
Forward current: More than the load current
Varistor
Varistor
Power Ind. Load
This protection circuit can be used for both AC and
DC load power circuits.
For a best result, when using a power voltage of 24
to 48V AC/DC, connect a varistor across the load.
When using a power voltage of 100 to 240V AC/DC,
connect a varistor across the contacts.
3. Do not use a contact protection circuit as shown below:
Power
CLoad
This protection circuit is very effective in arc suppression when
opening the contacts. But, the capacitor is charged while the
contacts are opened. When the contacts are closed, the capacitor
is discharged through the contacts, increasing the possibility of
contact welding.
CLoad
Power
This protection circuit is very effective in arc suppression when
opening the contacts. But, when the contacts are closed, a current
flows to charge the capacitor, causing contact welding.
Generally, switching a DC inductive load is more difficult than switching a DC
resistive load. Using an appropriate arc suppressor, however, will improve the
switching characteristics of a DC inductive load.
Soldering
1. When soldering the relay terminals, use a soldering iron of 30 to 60W, and
quickly complete soldering (within approximately 3 seconds).
2. Use a non-corrosive rosin flux.
Operating Instructions
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Other Precautions
1. General notice:
To maintain the initial characteristics, do not drop or shock the relay.
The relay cover cannot be removed from the base during normal operation. To
maintain the initial characteristics, do not remove the relay cover.
Use the relay in environments free from condensation, dust, sulfur dioxide
(SO2), and hydrogen sulfide (H2S).
Make sure that the coil voltage does not exceed applicable coil voltage range.
2. UL and CSA ratings may differ from product rated values determined by IDEC.
3. Do not use relays in the vicinity of strong magnetic field, as this may affect
relay operation.
Safety Precautions
• Turn off the power to the relay before starting installation, removal, wiring,
maintenance, and inspection of the relays. Failure to turn power off may
cause electrical shock or fire hazard.
• Observe specifications and rated values, otherwise electrical shock or fire
hazard may be caused.
• Use wires of the proper size to meet voltage and current requirements. Tight-
en the terminal screws on the relay socket to the proper tightening torque.
• Surge absorbing elements on AC relays with RC or DC relays with diode are
provided to absorb the back electromotive force generated by the coil. When
the relay is subject to an excessive external surge voltage, the surge absorb-
ing element may be damaged. Add another surge absorbing provision to the
relay to prevent damage.
Precautions for the RU Relays
• Before operating the latching lever of the RU relay, turn off the power to
the RU relay. After checking the circuit, return the latching lever to the origi-
nal position.
• Do not use the latching lever as a switch. The durability of the latching lever
is a minimum of 100 operations.
• When using DC loads on 4PDT relays, apply a positive voltage to terminals of
neighboring poles and a negative voltage to the other terminals of neighbor-
ing poles to prevent the possibility of short circuits.
• DC relays with a diode have a polarity in the coil terminals. Apply the DC volt-
age to the correct terminals.