Hobart 60CU20 Operation And Maintenance Manual With Illustrated Parts List page 117

OM-2226 / Operation and Maintenance Manual
60CU20 / Series 500062 / 400 Hz. Generator Set
Protective Circuit (continued)
Trouble, Symptom,
Condition
3. Load contactor opens
during power delivery.
Over frequency fault
indicated.
4. Load contactor opens
during power delivery.
Under frequency fault
indicated.
5. Load contactor opens
during power delivery.
Overload fault
indicated.
May 2, 2013
Revision 2
Probable Cause
a. Frequency adjust
switch is enabled.
b. Defective REG board
a. Frequency adjust
switch is enabled
b. Defective REG board
a. There may have been
an overload condition.
b. Defective CTL board
Test, Check, and/or Remedy
Set frequency adjust switch on the ESB board to
DISABLE
If over-frequency faults continue after engine's
ECM is proven to be good, and an over-frequency
condition does not exist, replace the REG board.
Set frequency adjust switch to DISABLE
If under-frequency faults continue after engine's
ECM is proven to be good, and an under-frequency
condition does not exist, replace REG board.
Observe the ammeter. Check for abnormal
overload conditions and correct. If the load
contactor opens when an overload does not exist,
proceed to step b.
Replace CTL board.
Chapter 2-4
Page 17