TM 5-3895-379-23
ALTERNATOR TEST
THIS WORK PACKAGE COVERS
Test
INITIAL SETUP
Equipment Condition
Tools and Special Tools
Engine off (TM 5-3895-379-10)
Tool kit, general mechanic's (Item 36, WP 0220 00)
Drums chocked (TM 5-3895-379-10)
Shop equipment, common no. 1 (Item 28, WP 0220
Right-side door assembly opened (TM 5-3895-379-
10)
References
TM 5-3895-379-23P, Figure 44
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 ten minutes of operating engine at full throttle, output voltage of alternator should be
28.0 +/-1 volt for a 24-volt system.
b.
After ten 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 0061 00) if voltage is below specification, decreases after matching specification or is consis-
tently above specification after ten minutes of operation.
6.
Close right-side door assembly (TM 5-3895-379-10).
7.
Remove chocks (TM 5-3895-379-10).
END OF WORK PACKAGE
