Hobart 60CU24, Operation And Maintenance Manual With Illustrated Parts List, Page: 87 / 234

OM-2098C / Operation and Maintenance Manual
60CU24 / Series 500060C / 400 Hz. Generator Set
April 01, 2005 Chapter 2-3
Page 9
NOTE: Make all protective system tests with the unit operating under a load for the following steps.
Reference Chapter 2, Section 4, for all fault codes.
(5) Check operation of over-voltage circuit and fault code display.
a With the unit running at a normal load, adjust the coarse adjustment potentiometer (Figure 8)
on the voltage regulator clockwise to increase voltage until the over-voltage sensing circuit
actuates the protective monitor. After the protective monitor is activated, the load contactor
will open and the fault code display will display fault “
70.16 ”. At 125 volts, the circuit will trip
after a 1-second time delay. At higher values of voltage, time delays for over voltage trips are
as follow:
•
At 140 volts, the circuit will trip within 160 milliseconds.
•
At 180 volts, the circuit will trip within 50 milliseconds.
b If the load contactor does not open under the conditions described in step (a), refer to the
Troubleshooting Chart in Section 2-4.
c Return unit to normal operating conditions by adjusting coarse adjustment potentiometer
(turning it counterclockwise) and pressing “
TEST/RESET ” button switch to clear the fault
code (Figure 2).
(6) Check operation of under-voltage circuit and fault code display.
With the unit running at a normal load, adjust the coarse adjustment potentiometer (Figure 8) on
the voltage regulator counterclockwise to decrease voltage until the under-voltage sensing circuit
actuates the protective monitor. After the protective monitor is activated, the load contactor will
open and the fault code display will display fault “
70.17 ”. Follow the following steps below to
activate the under-voltage protective monitor. A stopwatch is required for this check.
a With the unit running at normal load, use the output voltage coarse adjustment potentiometer
on the voltage regulator to reduce the voltage to 104 volts. The load contactor should NOT
open.
b Reduce voltage in increments of 1 volt, with a time delay of 7 seconds between steps. At a
setting of 100 volts, the load contactor will open and the under voltage light will glow after a 7-
second time delay.
c If the load contactor does not open under the conditions described, refer to the
Troubleshooting Chart in Section 2-4.
d If the under voltage circuit performs satisfactorily, return unit to normal operation by adjusting
output voltage coarse adjustment potentiometer for normal output voltage, pressing the
“
TEST/REST ” push button switch to clear the fault code.
(7) Check under-frequency circuit and fault code display.
At some frequency value 380 Hz or less, after 7 seconds, the frequency condition should signal
the under-frequency circuit protective monitor to OPEN the load contactor and display “
70.23 ” on
fault code display. To check the under-frequency protective components, proceed as follows: