MULTIQUIP DCA Series - Overcurrent Relay (OCR) Testing Procedure

GENERATOR SERVICE AND TROUBLESHOOTING MANUAL — REV. #0 (08/29/23) — PAGE 57
OVERCURRENT RELAY
(
OCR
)
OCR TESTING
1. Place the selection dial (Figure 60A) on the multimeter
to the W position, then select the sound icon.
2. Next, with the engine OFF and no power applied
to the relay, place the multimeter leads (Figure 60B)
across terminals 95 and 96 on the relay and verify
that there is continuity (beep! beep!). This implies a
CLOSED circuit, continuity.
3. PRESS the spring-loaded relay reset button
(Figure 60C).
4. Move the multimeter leads to terminals 97 and 98
(Figure 60D) on the relay and verify that there is no
continuity (no beep!). This implies an OPEN circuit,
no continuity.
5. To trip the OCR, slide the manual trip lever on the relay
as shown in Figure 60E and verify that the multimeter
indicates an OPEN circuit (no beep!) across terminals 95
and 96. This implies an OPEN circuit, no continuity.
6. Move the multimeter leads to terminals 97 and 98
on the relay and verify that there is continuity (beep!
beep!). This implies a CLOSED circuit, continuity.
NOTICE
Activating the test button while the unit is running will
shunt trip the main circuit breaker. Only perform with
no load on the generator.
Figure 60. OCR Trip Test
RESET
BUTTON
C
MANUAL
TRIP LEVER
E
MULTIMETER
BEEP!
BEEP! BEEP!
OVERCURRENT
RELAY
NO
NC
95 96
97 98
OVER-CURRENT
RELAY
DE-ENERGIZED
NO
NC
97 98
95 96
OVER-CURRENT
RELAY
TRIPPED
RELAY CONTACTS
95-96 CLOSED
DE- ENERGIZED
(CONTINUITY)
B
D
RANGE
MIN MAX
MULTIMETER
Auto0 600
OFF
Hz
C
A
mA
uA
F
V
Hz
V
mV
Hz %REL
HOLD/LIGHT
10 A
MAX
mAµA
COM
A
TURN SELECTION
DIAL TO POSITION
SELECT SOUND ICON