TM 5-3825-213-20
to field maintenance for adjustment of
side. The reading may not be 22
voltage regulator. Stop the engine
volts, but all three possible tests
(TM 5-3825-213-10) and disconnect
should show very close to the same
the rectifier-to-alternator cable at the
voltage.
alternator.
(12) Replace the alternator if the above test
(6)
With the multimeter set on the RX 1
vary more than 1 volt.
scale, measure resistance between
b. Removal.
Remove the alternator as
pins D and E of alternator connector.
illustrated in figure 50.
The reading should be approximately
c. Brush Replacement. Replace the brushes
2 ohms. However, any reading from
as illustrated in figure 51.
1.7 to 5 ohms is acceptable, since the
d. Cleaning and Inspection. Clean, inspect,
test is being made through the
and replace defective parts as necessary.
brushes and sliprings.
e. Installation.
Install the alternator as
(7)
With the multimeter set on the RM 100
illustrated in figure 50.
scale, test from any of the large pins
A, B, or C to the others. There should
102. Alternator Regulator Assembly
be no measureable resistance. Take
a. On-Unit Testing.
a resistance test from each pin to the
(1) Perform on-unit tests prescribed for
alternator ground. The reading should
alternator (par. 101) and rectifier (par.
be infinite.
(8)
Place the engine runoff switch to the
(2) Perform continuity testing on the
RUN position, but do not start the
regulator-to-rectifier cable in the same
engine.
manner as prescribed for rectifier-to
Note. When the runoff switch is
alternator cable (par. 101).
placed to RUN, the load relay in the
(3) Disconnect
voltage
regulator-to-
voltage regulator can be heard
terminal board cable at the voltage
closing.
regulator. Set a multimeter on the
(9)
With the multimeter set on the 50volt,
50volt, dc scale. Check from socket A
dc scale, test between small socket D
of cable to ground. The meter reading
and small socket E at the alternator
should be 24 volts.
end of the rectifier-to-alternator cable.
(4) Connect a jumper wire from socket A
The reading should be approximately
to socket B. Bypass the oil pressure
25 volts.
switch to apply 24 volts to pin F of
(10)
Reconnect rectifier-to-alternator cable.
voltage regulator-to-terminal board
(11)
Start the engine and run it at
cable. Check from socket F to socket
approximately 700 to 800 rpm. With
C. Battery voltage of 24 volts should
the voltmeter set on the 50-volt, ac
be indicated on meter.
scale,
test from each of the ac
(5) Set multimeter on RX 10 scale and
connections on the rectifier to the
check from pin F to pin C of voltage
other two connections.
regulator-to-terminal board cable. The
Note.
The ac connections, are
line switch coil resistance reading on
the meter should indicate 175 10
identified by yellow dots adjacent
to each of the three connections.
ohms.
Because
of
peculiarities
of
(6) Disconnect the voltage regulator-
alternating current, the meter will
torectifier cable and leave the voltage
regulator-to-terminal
board
cable
not read peak voltage of each back-
disconnected. With the multimeter set
and-forth (alternating) cycle, but
on RX 1 scale, check from socket C to
will only record an average value.
socket B of the voltage regulator to-
Even through an output of 27.5
rectifier cable.
The carbon pile
volts or more is indicated on the dc
resistance reading should be 1 ohm.
side of rectifier, a reading of 22
volts will be indicated on the ac
85
