Load Contactor Operating Circuits - Hobart 60CU20 Operation And Maintenance Manual With Illustrated Parts List

OM-2226 / Operation and Maintenance Manual
60CU20 / Series 500062 / 400 Hz. Generator Set

Load Contactor Operating Circuits

Output 1: Contactor K1, Pushbutton switch S75
Output 2: Contactor K201, Pushbutton switch S275
Trouble, Symptom, Condition
1. Load contactor will not close
when the corresponding
Output pushbutton switch is
held in closed position.
Generator is running at normal
voltage.
May 2, 2013
Revision 2
Probable Cause
a. Blown contactor fuse (F3) on
regulator board
b. Defective Output pushbutton
switch
c. Defective Voltage Regulator
(REG) board
d. Defective coil in load contactor
Test, Check, and/or Remedy
Check the fuse and replace if
blown. If it blows again, check the
contactor.
At rated speed, measure the
voltage across the switch. The
voltage should read approximately
5 VDC when the switch is open
and 0 V when the switch is closed.
If voltage does not go to 0 V, the
switch is defective and needs to be
replaced.
Measure the DC output voltage at
contactor coil. If the voltage
measured isn't approximately 90
VDC, replace REG.
Replace the REG board.
Disconnect leads at load contactor
terminals V and W. Check coil
resistance between these
terminals. Resistance should be
approximately 600 ohms. If coil is
defective, replace the contactor.
Chapter 2-4
Page 14