Testing - TM-9-2920-258-30-P0054

TM 9-2920-258-30&P

b Testing

1 Start the varidrive by actuating the start button (28) and turn the drive speed control (42)

counterclockwise until the Alternator is operating at 2800 rpm.

2 Place the battery selector (31) in the 24V position.

3 Snap IGN (ignition) switch ON.

4 Turn the field current control (41) fully clockwise.

5 To obtain a 180A load snap the 100A, 50A, 25A, and 0-25A switches, of the load bank switches

(34), and the master load switch (39) in the ON position.

6 Adjust the load current control (43) by turning clockwise until the reading on the DC ammeter (load

and starter) reads 180 amperes.

CAUTION

Never allow the voltage (DC voltmeter) to exceed 32 volts or the ampere reading on the DC ammeter

(field and battery) to exceed 15 amperes or the rectifier maybe damaged.

7 At this point the DC ammeter (load and starter) should read 180 amperes and the DC voltmeter

should read 28 volts.

8 The DC ammeter (field and battery charger) should read between 9 and 11 amperes. If the

voltage drops below 27.5 volts, the regulator requires adjustment.

9 Rotate the AC ammeter phase selector (10) through the A, B and C positions; the AC ammeter

should read approximately the same in all positions.

10 Rotate the AC voltmeter circuit selector (12) through the T1 -T2, T1 -T3, and T2-T3 positions; the

AC voltmeter should be approximately the same in all positions.

11 If the DC ammeter (field and battery charger) reads over 12 amperes or other tests are not

conclusive, check the Alternator without the regulator in the circuit to determine which

unit will require repair.

12 Using a multimeter, place the red lead on terminal "ac'" and ground the black lead. Check for 12-

16 volts AC.

Test Stand Shutdown

1 Turn the ignition switch OFF.

2 Turn the master load switch OFF.

3 Turn the battery switch OFF.

4 Reduce test stand speed to 1000 rpm.

5 Depress the STOP button

6 Return all switches and controls to the base setting.

D-6