DYNAMIC BENCH TEST PROCEDURES

TM 9-2920-257-30&P

2-7. DYNAMIC BENCH TEST PROCEDURES

a. Confirm results of On-Vehicle test by these bench tests if possible. When it is not possible to perform On-Vehicle

tests, check generator performance quickly by referring to these bench tests.

NOTE

Test bench must have a 20 Hp motor or larger, capable of driving the generator to

7000 RPM, a multimeter (App D, Item 3) with 0-400 amp range, and 0-40 volt range.

b. Mount generator on test bench according to the bench manufacturer's instructions. Refer to Figure 2-13 for set-

up to measure voltage and amperage produced by generator. For bench tests, voltage is normal when it is within the

normal range of Table 2-2, and amperage is high when it is within +/- 10 % of rated output (output 5000 RPM).

c. Run the No-Load Test without electrical load, but with batteries connected. Run generator at 5000 RPM and refer

Table 2-4. NO-LOAD TEST DIAGNOSIS

AMPS

VOLTS

DIAGNOSIS

TEST BENCH BATTERY DISCHARGED OF DEFECTIVE.

HIGH

LOW

ALLOW TO CHARGE OR REPLACE.

ALLOW TIME TO STABILIZE WHILE MONITORING

VOLTS. IF VOLTS RISE ABOVE NORMAL RANGE (25V-

HIGH

NORMAL

31V), REGULATOR AND/OR FIELD COIL MUST BE

REPLACED. IF AMPS FALL, CHARGING SYSTEM IS

OKAY.

STOP TEST. REGULATOR AND /OR FIELD COIL MUST

HIGH

BE REPLACED. GO TO STATIC TESTS

GENERATOR AND/OR REGULATOR MUST BE

LOW

REPAIRED OR REPLACED.

LOW

NORMAL

REGULATOR IS GOOD, GO TO FULL-LOAD TEST.

STOP TEST. BENCH MALFUNCTION OR WIRING

LOW

HIGH

ERROR.

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