ARMY TM 9-6115-644-24
AIR FORCE TO 35C2-446-12
MARINE CORPS TM 09249A/09246A-24/2
b. Place Master Switch in OFF position. Connect multimeter leads to terminals 19 & 20 on the governor control
unit (A-5), then move master switch to START position. Reading should be battery voltage when generator does
not crank. If there is no voltage between terminal positions, the GCU (A-5) is not functioning properly and should
be replaced.
NOTE
With the generator running there will be battery voltage.
c.
Place Master Switch in OFF position. Connect multimeter leads to terminals 19 & 18 on the governor control
unit (A-5), then move master switch to START position, reading should be zero voltage when generator does
not crank. If there is voltage between the terminal positions, the GCU (A-5) is not functioning properly and should
be replaced.
4-3-2 Testing.
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
m.
Shut down generator set.
Open output box access door. Remove protective cover and attach voltage and frequency recorder to terminals
9 and 12 of voltage reconnection terminal board.
Open load terminal board access door and attach load bank to generator set (4 wire connection).
NOTE
Ensure load bank and generator set voltage reconnection are set for same configu-
ration (i.e., 120/208 or 240/416 VAC).
Start and operate generator set at rated voltage and frequency.
Turn on voltage and frequency recorder and operate at minimum chart speed of 5 mm/sec (chart resolution of
0.2 sec/mm). Adjust recorder voltage amplifier for a minimum chart resolution of 1.0 volt/mm, and frequency
deviation amplifier for a minimum resolution of 0.2 Hz/mm.
Set load bank for a load equal to 75% of generator set rated load.
Apply and remove the 75% load to the generator set at 40 second intervals three times.
Repeat steps f and g at 50% rated load.
Repeat steps f and g at 25% rated load.
Repeat steps f and g at 100% rated load.
Shut down generator set.
Turn off voltage and frequency recorder.
Examine voltage and frequency recorder chart. Generator set should meet the following performance criteria:
(1)
Frequency regulation shall not exceed 1/4 of 1 percent of rated frequency.
(2)
Frequency short-term stability (30 seconds), frequency will remain constant within a band width equal
to 1/2 of 1 percent rated frequency, without repetitive frequency variations, commonly called “hunting”.
4-6
