TM 5-3895-379-23-1
FIELD MAINTENANCE
ALTERNATOR TEST
INITIAL SETUP:
Tools and Special Tools
Equipment Condition (cont.)
Tool Kit, General Mechanic's: Automotive
Drums chocked. (TM 5-3895-379-10)
Right-side door assembly opened.
(Volume 2, WP 0289, Table 1, Item 39)
(TM 5-3895-379-10)
Personnel Required
Construction Equipment Repairer 91L
References
Equipment Condition
Engine off. (TM 5-3895-379-10)
TEST
1.
Place positive (+) lead of multimeter on alternator BAT terminal. Place negative (-) lead on ground terminal or
frame of alternator. Place ammeter around positive output wire of alternator.
2.
Turn off all electrical accessories. Turn off fuel to engine. Crank engine for 30 seconds. Wait for two minutes
to cool starting motor. If electrical system appears to operate correctly, crank engine again for 30 seconds.
NOTE
Cranking engine for 30 seconds partially discharges batteries to perform charging test. If
battery has a low charge, do not perform this step. Jump start engine or charge battery before
engine is started.
3.
Start engine and run at full throttle (TM 5-3895-379-10).
4.
Check output current of the alternator. Initial charging current should be equal to minimum full load current or
greater than minimum full load current. Minimum full load current at 5000 rpm = 47 amps and at 1500 rpm
= 13.5 amps.
a.
After approximately 10 minutes of operating engine at full throttle, output voltage of alternator should be
28.0 +/-1 volt for a 24-volt system.
b.
After 10 minutes of engine operation, charging current should decrease to approximately 10 amps. Actual
length of time for charging current to decrease to 10 amps depends on battery charge, ambient
temperature, and rpm of engine.
5.
Replace alternator (WP 0148) if voltage is below specification, decreases after matching specification or is
consistently above specification after 10 minutes of operation.
END OF TASK
0149-1
03/15/2011Rel(1.8)root(maintwp)wpno(M00087)
