TM-9-2320-280-34

TRUCK, UTILITY: M998 SERIES

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE

JANUARY 1996
TM-9-2320-280-34

  TM-9-2320-280-34 - Page 365 of 1258

6 - 5 . 200 AMPERE ALT E R N ATOR (12338796-1) TESTING AND REPAIR (Cont'd)
b. Disassembly
9.
Regulator Bypass Test.
NOT E
Perform this test only when instructed from tables 6-A.7 and 6-B.
(a) Prepare alternator as in full load test.
NOT E
Use jumper wire rated for 15 amps.
NOT E
Complete alternator disassembly is not required for static testing.
1.
Remove voltage regulator (TM 9-2320-280-20).
1.1.
Install core and shaft assembly (11) in soft-jawed vise and remove locknut (6), washer (5), and
fan (4) from core and shaft assembly (11). Discard locknut (6).
2.
Remove bearing bushing (3) from core and shaft assembly
(11).
3.
Remove three screws (20), lockwashers (21), and plate cover (19) from front housing (17). Discard
lockwashers (21).
4.
Scribe alignment marks on front housing (17), stator (9), and end housing (2).
5.
Remove nine locknuts (7) from end housing (2) and stator (9). Discard locknuts (7).
6.
Use puller to remove end housing (2) from stator (9).
7.
Remove six locknuts (1) from rear rotor (24) on core and shaft assembly (11). Discard
locknuts (1).
8.
Use three 10-32 x 2-in. long machine screws as jacks in threaded holes on end plate of rear
rotor (24). Gradually tighten screws to remove rear rotor (24) from core and shaft assembly (11).
Remove rear rotor (24) and screws.
NOT E
Prior to removal, tag leads for installation.
9.
Remove eight nuts (18) and disconnect two field and six phase leads (8) from diodes in front
housing (17).
10.
Remove nine locknuts (22) from front housing (17) and stator (9). Discard locknuts (22).
11.
Remove front housing (17) from stator (9) by tapping lightly with a soft-faced mallet.
CONNECT
DISCONNECT
DIAGNOSIS
AMPS RISE
AMPS FALL
Alternator OK. See note. Replace regulator
only if low AMPS (80-119)/low VOLTS (21-25)
are indicated in table 6-A.7 and/or table 6-B.
NO CHANGE
NO CHANGE
Alternator must be repaired. Refer to Static
Testing.
Table 6-C. Regulator Bypass Test.
TM 9-2320-280-34
6 - 4 0
Change 1
(b) Disconnect alternator connector from regulator. With alternator spinning, use jumper wire and
short pin A of connector to ground momentarily. Record results.
(c) Amperage should rise within ± 10% of rated output with jumper wire connected and fall with
jumper disconnected. Refer to Table 6-C, Regulator Bypass Test, for diagnosis.
10.
Turn test stand master power switch and load switch to OFF.
11.
Disconnect jumper wires from terminals on test stand and alternator.


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