TM-9-2320-280-34
TRUCK, UTILITY: M998 SERIES
TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE
JANUARY 1996
TM-9-2320-280-34 - Page 385 of 1258
TM 9-2320-280-34
6 - 4 4 . 1 6
Change 1
6±-±5±
.±2±
. 400 AMPERE DUAL VOLTAGE ALT±E±R±N±ATOR (12469057) TESTING AND REPAIR (Cont'd)
Table 6-I. Full-Load Test.
AMPS
28VDC
14VDC
DIAGNOSIS
322-400
21-25
10.5-12.5
Test bench battery is discharged (or defective).
Allow to charge (or replace).
322-400
26-30
13-15
Charging system OK.
322-400
31-35
15.5-17.5
STOP TEST. Regulator and/or tube assembly
must be replaced. Refer to static testing, task c.
160-238
21-25
10.5-12.5
Alternator and/or regulator must be replaced.
Refer to table 6-K.
160-238
26-30
13-15
Increase load.
160-238
31-35
15.5-17.5
STOP TEST. Test bench malfunction or wiring
error.
ALTERNATOR
28VDC
14VDC
SPEED
OUTPUT CURRENT
OUTPUT CURRENT
(RPM)
²5 AMP
MINIMUM AMP
*3
45
10
38
1200
20
28
30
18
**44
4
*5
20
10
30
1500
50
50
100
50
140
50
160
30
*187
3
*5
16
2000
60
30
97
50
120
50
ALTERNATOR
28VDC
14VDC
SPEED
OUTPUT CURRENT
OUTPUT CURRENT
(RPM)
²5 AMP
MINIMUM AMP
255
50
2000
275
30
**302
3
*5
10
70
20
3500
200
50
350
50
380
20
**397
3
*5
10
5000
70
20
TO
200
25
8000
350
40
380
20
**397
3
Table 6-J. Alternator Speed and Current Tracking.
* Dependent on ammeter location in test circuit.
**Minimum acceptable current with no load on 28 VDC system.
24.
Perform full-load test. Ensure all load switches are in ON position on test stand, and increase
alternator speed to 5000 rpm. Set load to 364 amps/min; record results. Refer to table 6-I, Full-Load
Test, for diagnosis.
25.
Alternator speed and current output tracking values. Refer to table 6-J.
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