4.
Test Values
Although test values are provided throughout the troubleshooting chart , additional information and
values are given here.
Generator output voltage at maximum voltage regulator potentiometer setting: 134 volts or higher.
Generator output voltage at minimum voltage regulator potentiometer setting: 108 volts or lower.
Over voltage relay
Trips at 126 volts after a 1-second time delay.
Trips at 140 volts in 160 milliseconds.
Trips at 180 volts in 50 milliseconds.
Under voltage relay
Trips at 100 volts after 7 seconds.
Over frequency relay
Trips at any value between 426-Hz and 480-Hz after a
5-second time delay. Trips immediately at any frequency
exceeding 480-Hz.
Under frequency relay
Trips at 375 Hz or less after a 5-second time delay.
Overload time delay
Trips in approximately 5 minutes at 125% load on either output
or on both
Frequency at rated speed of 2400 RPM is 400 +/- 2 Hz at no load and rated load.
Engine oil pressure (warm and at rated speed 2400 RPM) 45 to 90 PSI (445 to 621 kPa).
Engine coolant temperature (normal operation) 160 to 200º F (71 to 93º C).
5.
Check Connections and Leads
ALWAYS make a check of connections and leads to a component suspected of being faulty. With the
exception of a few instances, we will assume that connections and wiring have always been checked
first and that power has not been lost as a result of defective wiring or connections.
6.
Electric Governor Troubleshooting
The following facts concerning the operation of the electric governor may be helpful in understanding
the system and in determining which unit in the system is faulty in case of troubles.
(1)
The system requires two sources of power to operate normally.
a.
12 V DC input power (from engine electrical system)
b.
4 V AC input voltage normal, the actuator will go to, or remain in
STOP
position under the
following conditions:
•
No 12 V DC power
•
No voltage from control box to actuator
•
Inadequate magnetic pickup voltage
OM-2084 / Operation and Maintenance Manual
90CU24 / Series 500392 Generator Sets
Chapter 2-4
November 27/1997
Page 2
