PAGE 56 — GENERATOR SERVICE AND TROUBLESHOOTING MANUAL — REV. #0 (08/29/23)
OVERCURRENT RELAY
(
OCR
)
OVERCURRENT RELAY
The overcurrent relay (OCR) is a circuit/load protection
device. In the event of an overload, both the circuit breaker
and the OCR may trip. If the circuit breaker cannot be reset,
the reset button on the OCR must be depressed.
NOTICE
The reset button is spring operated, it will always
appear tripped. If the OCR was indeed tripped, the
operator will feel a detent when the button is depressed.
The OCR is a plug-in device that plugs into a relay
base located inside the box. Figure 59 provides a brief
explanation of the control dials and the various components
that interface with the OCR.
Figure 59. Overcurrent Relay
IMPORTANT! AMP range setting is preset at
the factory per generator model. DO NOT ADJUST.
If changed main circuit breaker may not trip.
Reference Table XX for correct factory setting.
AMMETER
AMMETER
SWITCH
TERMINALS 98 AND 97
ARE SIGNALING CONTACTS
CONNECTED TO MAIN BREAKER.
THESE CONTACTS WILL SHUNT
TRIP THE MAIN BREAKER IN AN
OVERLOAD CONDITION.
OCR SNAP-ON
MOUNTING BASE
LOCATED INSIDE
CONTROL BOX
TERMINALS 1, 3 AND 5 ARE
SENSING CONTACTS AND
ARE CONNECTED TO
CURRENT TRANSFORMERS
CT1, CT2 AND CT3
NOTICE
If replacing OCR be sure to use
factory settings of original OCR.
Reference Table XX for correct
factory setting.
Manual/Auto reset selection dial.
This dial is preset at the factory
and is set to the manual position
and should not be changed.
NOTICE
The Manual/Auto dial must remain in the
MAN position, if placed in the Auto position
relay will automatically reset after a release
(trip) and could cause damage to the
equipment and bodily harm to personnel.
The RO/R selection dial is
preset to the RO position.
RO = Reset and turn OFF
R = Reset only
TEST TRIP
LEVER
CIRCUIT
BREAKER
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