ARMY TM 9-6115-464-34
AIR FORCE 35C2-3-445-2
NAVY NAVFAC P-8-624-34
Table 3-7. Electric Governor Malfunction Testing
PROBABLE CAUSE OF
TERMINAL
NORMAL
NON-NORMAL READING
CORRECTIVE ACTION
S
1.0 volt AC-RMS
1. Defective magnetic pickup.
minimum while cranking. 2. Gap too large between
magnetic pickup and gear
teeth.
3. Improper or defective wiring
to the magnetic pickup.
1. Replace magnetic pickup.
2. Readjust magnetic pickup.
3. Replace wiring harness.
K
10.1±.20 volts DC while 1. DC power not connected or
energized (Internal
low battery voltage.
regulated D.C. supply).
2. Frequency trim potentiometer
shorted, grounded or
miswired.
3. Wiring error.
4. Defective control unit.
L
Above 5.1 volts DC while 1. Frequency adjust set too low.
running. (inverse speed
error signal).
2. Defective control unit.
Above 5.1 volts is under
speed signal. Below 5.1
volts is over speed signal.
On speed will indicate a
steady 5.1 volts.
N
8.5 to 9.5 volts DC while 1. Battery voltage maybe too
cranking. (Proportional
low while cranking.
actuator voltage).
2. Defective control unit.
R
2.5 volts DC maximum
1. Output transistor open (defec–
while cranking. (Tran-
tive control unit).
sister voltage).
2. Defective actuator.
3. Error in wiring to actuator.
(13)
(14)
1. Connect DC power supply;
replace DC battery.
2. Replace control unit.
3. Replace wiring harness.
4. Replace control unit.
1. Turn frequency adjust
screw clockwise.
2. Replace control unit.
1. Charge DC battery; replace
DC battery.
2. Replace control unit.
1. Replace control unit.
2. Replace actuator.
3. Replace wiring harness.
NOTE
Two people will be required to adjust the control unit. Ensure that the actuator linkage
rod and all levers are securely fastened and move freely (without binding) before
operating the engine. Manually overcome the actuator until adjustment of the control
unit is completed and the governor is in control. Adjustment of the control unit will be
made with the engine operating in a no–load condition.
Start the engine, manually operating the fuel shutoff lever.
Turn the control unit frequency adjust screw clockwise until the proper engine speed is obtained.
Several turns may be required. The generator set frequency adjust pot should now have sufficient
adjustment travel to cause the generator set frequency meter to indicate beyond both of its extreme
limits (388-412 Hz).
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