STARTING MOTOR ARMATURE END PLAY ADJUSTMENTS

TM 10-3930-623-34

2. Inspect drive spring for distortion and damage.

2. Close test switch and adjust variable resistance

Discard damaged drive spring.

to obtain a voltmeter reading of 9.0 volts. The ammeter

reading must be between 53 and 69 amperes.

7-29.

STARTING MOTOR ARMATURE END PLAY

3. Place a mechanical tachometer on drive end of

ADJUSTMENTS.

armature shaft and check for speed. Correct speed at

1. Align drive end of armature shaft with plunger of

current and voltage specified in step 2 is 6400 to 8600

a dial indicator. Pull shaft out toward drive end to outer

rpm.

limit and set dial indicator.

4. If test indicates low speed and high current,

2. Push armature shaft in toward commutator end

recheck armature for shorts or grounds. If armature

of starting motor assembly to inner limit. Note dial

appears to be satisfactory, check for loose pole shoes

indicator reading. End play must be between 0.005 and

and defective bearings.

0.062 inch.

5. If test indicates low speed and low current,

3. If end play exceed these limits, add or remove

examine commutator, brushes, and brush leads. Check

thrust washers at drive end of armature shaft to obtain

brush spring tension.

proper end play.

7-31.

STARTING MOTOR STALL CURRENT AND

7-30. STARTING MOTOR NO-LOAD CURRENT AND

TORQUE TEST.

SPEED TEST.

1. Connect starting motor assembly to test circuit

1. Connect starting motor assembly to test circuits

(figure 7-5). Be sure equipment used has sufficient

capacity to handle test, anticipating possible electrical

2. Close test switch and adjust variable resistance

overloads if the starting motor is defective.

to obtain a voltmeter reading of 5.8 volts. Ammeter

reading shall not exceed 435 amperes. Record torque

value as

Figure 7-5. Starter No-Load Current and Speed Test Setup

7-11