Hobart 60CU20 Operation And Maintenance Manual With Illustrated Parts List page 120

OM-2226 / Operation and Maintenance Manual
60CU20 / Series 500062 / 400 Hz. Generator Set
T-R Controls and Components (continued)
Trouble, Symptom, Condition
2. (continued)
3. STARTING CURRENT push
button sets the current limit,
but the system is not current
limiting.
4. STARTING CURRENT push
button does not increment
the current limiting values.
May 2, 2013
Revision 2
Probable Cause
e. Interlock signal not being
received from the aircraft
a. Defective push button switch
b. Defective TRB Board
a. Defective push button switch
b. Defective TRB Board
Test, Check, and/or Remedy
Be sure the output cable is properly
inserted into the aircraft receptacle and
try again.
Verify 28 VDC is on the DC+ connection
of the GPU and/or being sent from the
aircraft.
If aircraft is sending signal but not being
received at the GPU DC+ and the cable
is properly inserted into the aircraft
receptacle, verify the K403 relay is
operating.
If K403 relay is operating, replace output
cable.
If all the above appears to be working,
replace the TRB board.
At rated speed, measure the voltage
across the switch. The voltage should
read approximately 5 VDC. Press the
switch again and the voltage should go
to 0 V. If voltage does not go to 0 V, the
switch is defective and needs to be
replaced.
Replace TRB board with a board known
to be operating properly. If current
limiting is still not operating, contact the
factory.
At rated speed, measure the voltage
across the switch. The voltage should
read approximately 5 VDC. Press the
switch again and the voltage should go
to 0 V. If voltage does not go to 0 V, the
switch is defective and needs to be
replaced.
Replace TRB board with a board known
to be operating properly. If contactor
still doesn't close, contact the factory.
Chapter 2-4
Page 20