ARMY TM 9-6115-644-24
AIR FORCE TO 35C2-3-446-12
MARINE CORPS TM 09249A/09246A-24/2
The generator set will reestablish stable engine operating conditions within 2 seconds of a sudden load
change (within 1 second for 400 Hz unit). The maximum transient frequency change above or below
(overshoot or undershoot) the new steady state frequency shall not be more than 4 percent of rated fre-
quency (not more than 1-1/2 percent for 400 Hz unit).
If the above criteria is not met, adjust the governor control unit (3, FIGURE 4-3) in accordance with paragraph
If the above criteria cannot be met by adjustment, the governor control unit must be replaced.
Disconnect load bank and dose load terminal board access door.
Disconnect voltage and frequency recorder, install voltage reconnection terminal board protective cover and
dose output box access door.
a. Shutdown generator set.
b. Open output box access door, remove cover from voltage reconnection terminal board and attach voltage and
frequency recorder to terminals 9 and 12 of voltage reconnection terminal board.
The following procedures require monitoring frequency, voltage, current, and power.
All readings except for frequencies will utilize the generator set control panel gages.
However, since the designed overspeed trip frequency is greater than the range of
the control panel FREQUENCY meter (HERTZ), a frequency counter will be required.
Attach frequency counter to voltage reconnection terminal board terminals 9 and 12.
d. Open load terminal board access door and attach load bank to generator set (four wire connection).
Ensure load bank and generator set voltage reconnection are set for same configu-
ration (i.e., 120/206 or 240/416 VAC).
e. Check for proper adjustment of governor actuator, paragraph 4-15-4. Adjust as necessary.
Check for proper adjustment of magnetic pickup, paragraph 2-110-4. Adjust as necessary.
Lower generator set control panel and turn INTEG, WV GAIN, and LOAD PULSE potentiometer on governor
control unit to their full counterclockwise positions.
It is necessary to adjust fuel injection pump high idle stop screw to allow increased
engine idle speed for overspeed test. Record number of turns so screw can be reset
h. Loosen jam nut (1, FIGURE 4-2) and back out high idle stop screw (2) on fuel injection pump.