TM 9-6115-664-13&P
5-16. ALTERNATOR MAINTENANCE
This task covers testing, removal, inspection, and installation
INITIAL SETUP
Tools:
Equipment Condition:
Shop Equipment, Automotive Maintenance
APU Shut Down
and Repair (Item 4, App. B)
Alternator Tool / Test Set (Item 7, App. B)
A. TESTING. The following tests shall be conducted when the APU fails to generate voltage or voltage generated is
below rated level. These tests are designed to isolate the cause of the fault.
1.
Battery power must be supplied to the alternator's B+ terminal to perform these tests. If contactor (main power
relay) will not, or cannot, engage, the contactor must be bypassed out of the circuit to complete the tests. Bypass
the contactor, if required, as follows:
a.
Disconnect power from the APU by unplugging NATO connector.
b.
Open top rear cover on APU enclosure by turning latches. Remove fuel module cover.
c.
Look into fuel module and locate B+ and B- terminals on rear of NATO connector. B+ terminal is insulated. B-
terminal is not insulated.
d.
Locate ALTERNATOR POSITIVE terminal on outside panel of fuel module.
e.
Connect test cable #1 (red wire cable) from NATO connector B+ terminal to ALTERNATOR POSITIVE terminal.
f.
Reconnect NATO connector to APU. Contactor is now bypassed.
2.
Disconnect APU wiring harness from the round alternator control receptacle (Figure 5-10). This disconnects
alternator from APU control panel.
3.
Connect plug end of test cable #2 (brown wire cable) to the round alternator control receptacle. Connect alligator
clip end of cable #2 to the alternator's B+ output stud. Completing this connection will energize the regulator,
turning on the alternator.
NOTE
Test cable #2 has pins C and D connected for use with the N3120 regulator. Pins C
and D are not used on the N3129 regulator and have no effect on the circuit.
4.
Disconnect the regulator electrical connector from regulator.
5-52
