ARMY TM 9-6115-645-24
AIR FORCE TO 35C2-3-444-12
MARINE CORPS TM 09244A/09245A-24/2
(1) Turn FREQ range potentiometer counterclockwise until frequency counter indicates midrange of over-speed
trip frequency [Example: 66 Hz (MEP- 806A)].
(2). Turn OVERSPD control potentiometer on governor control unit counterclockwise until generator set shuts
down.
(3)
Activate OVERSPD RESET switch.
(4)
Repeat steps i. and j
I.
If generator set shuts down prior to reaching lower limit of frequency noted in step j., proceed as follows:
(1) Turn OVERSPD control potentiometer clockwise one turn for each hertz generator set shut down prior to
lower frequency limit.
(2)
Activate OVERSPD RESET switch.
(3)
Repeat steps i. and j
m.
Actuate OVERSPD RESET switch.
n.
Loosen jam nut (1, FIGURE 4-2), set high idle stop screw (2) to position recorded for step h., and tighten jam nut
(1).
o.
Turn FREQ range potentiometer on governor control unit two turns, counter dock wise.
p.
Start and operate generator set at rated voltage and turn FREQUENCY adjust potentiometer on control panel to
midrange.
q.
Turn FREQ range potentiometer until rated frequency (50, 60 or 400 Hz) is indicated on control panel FRE-
QUENCY meter (HERTZ).
r.
Set load bank for generator set rated load and apply load. Observe generator set instruments and adjust load as
needed to ensure rated load is applied.
s.
Set multimeter for DC volts and connect to terminals 11 and 12 of governor control unit (3, FIGURE 4-3). t. Adjust
LOAD SHARING ADJUST rheostat until multimeter indicates 6 VDC. Disconnect multimeter.
u.
Remove load.
v.
Turn on voltage and frequency recorder and operate at minimum chart speed of 5 mm/sec (chart resolution of 0.2
mm/sec). Adjust recorder voltage amplifier for minimum chart resolution of 1.0 volt mm and frequency deviation of
0.2 Hz/mm.
w.
Adjust GOV GAIN potentiometer on governor control unit as follows:
(1) Turn GOV GAIN potentiometer to its full clockwise position.
(2) Momentarily actuate and turn off LOAD switch on control panel.
(3) Observe strip chart on recorder for frequency oscillation (hunting). If required, slowly turn GOV GAIN
counterclockwise until frequency oscillation disappears.
x.
Apply and remove rated load to generator set at 40-second intervals. Repeat this step two more times.
y.
Shut down generator set and turn off recorder.
z.
Examine voltage and frequency strip chart for the following performance criteria:
(1)
Frequency regulation shall not exceed 1/4 of one 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 (hunting).
(3) The generator set will reestablish stable engine operation within two seconds of a sudden load change (i.e.,
from a load to no-load condition (within one second for 400 Hz units). The maximum transient frequency
change above (overshoot) and below (undershoot) the new steady state frequency shall not be more than 4
percent of rated frequency (not more than 1-1/2 percent for 400 Hz units).
NOTE
All required INTEG and LOAD PULSE potentiometer adjustments will be in 10 percent increments.
Change 2 4-7
