ARMY TM 9-6115-645-24
AIR FORCE TO 35C2-3-444-12
MARINE CORPS TM 09244A/09245A-24/2
CHAPTER 4
DIRECT SUPPORT MAINTENANCE INSTRUCTIONS
SECTION I. MAINTENANCE OF CONTROL BOX ASSEMBLY
4-1
AC VOLTAGE REGULATOR.
WARNING
High voltage Is produced when this generator set is In operation. Improper operation could result
In personal Injury or death.
4-1.1
Testing. (Regulator. P/N: 122-3056 For MEP-806A Generator Set).
a.
Shut down generator set.
b.
Open output box access door.
c.
Note position of voltage reconnection terminal board and set FREQUENCY SELECT switch to 60 Hz position.
d.
Start generator set and turn VOLTAGE adjust potentiometer to ensure the adjustment ranges on TABLE 4-1
are met, depending on position of voltage reconnection terminal board.
e.
Shut down generator set.
f.
If no voltage or low voltage was indicated, or voltage adjustment range could not be achieved, perform the
following steps. Otherwise, AC voltage regulator (2, FIGURE 4-3) is serviceable.
g.
Disconnect wire 141A from terminal 1 of AC voltage regulator.
h.
Set multimeter for DC volts and connect positive lead to wire 141 A. Connect negative lead of multimeter to
terminal 3 of AC voltage regulator. Start generator set and operate at rated frequency. Move and hold
MASTER SWITCH in START position. Multimeter should indicate between 4 and 12 VDC. If no voltage,
proceed to troubleshooting governor control unit, paragraph 4-2.
i.
Shut down generator set. Isolate wire 141 A.
j.
Set multimeter for AC volts and connect to terminals 10 and 11 of AC voltage regulator. Start generator set
and operate at rated frequency. Move and hold MASTER SWITCH in START position. Multimeter should
indicate 280 to 360 VAC. If no or low voltage is indicated, proceed to troubleshooting the transformer,
paragraph 4-12. *
k.
Shut down generator set.
I.
Disconnect wire 137A from terminal 5 of AC voltage regulator. Set multimeter for ohms and connect positive
lead to wire 137A and negative lead to terminal 4 of AC voltage regulator. Move VOLTAGE adjust
potentiometer to full counter clockwise position. Multimeter should indicate approximately 3,000 ohms with
FREQUENCY SELECT switch in 60 Hz position, and approximately 0 ohms with FREQUENCY SELECT
switch in 50 Hz position. Move VOLTAGE adjust potentiometer clockwise slowly while observing multimeter.
Multimeter should increase smoothly to approximately 10,000 ohms.
m.
Place frequency select switch in the 60Hz position.
n.
If steps h., j., and I. are as indicated above, AC voltage regulator is defective and must be replaced.
NOTE
To replace voltage regulator see paragraph 4-1.4 and 4-1.5
o.
Connect all wires previously disconnected.
p.
Close output box access door.
TABLE 4-1. Voltage Adjustment Range (MEP-806A)
Voltage Reconnection Terminal Board Position
Adjustment Range
120/208
240/416
197-240 volts
395-480 volts
Change 2 4-1
