Section V. TESTING

TM 9-2920-242-35

Section V. TESTING

(1) Connect a 24-volt battery in series with an

37. GENERAL

ammeter and variable resistance to the

Whenever a starter is tested check for any

battery terminal of the solenoid.

unusual noises or vibration that might indicate an

unserviceable condition. If either condition exists,

For the return circuit, connect a lead from

further testing should not be attempted and the

the frame of the starter to the battery.

starter must be disassembled and repaired.

Connect a voltmeter from the solenoid

"BAT" terminal to ground. Energize the

38. NO-LOAD TEST AND LOCK TORQUE TEST

solenoid by connecting a jumper lead

from the solenoid battery terminal to the

Caution: Never operate the starter motor

solenoid switch terminal. Check the

more than 30 seconds at a time. Allow the motor

rotation speed of the armature with a

to cool for at least 2 minutes between each

tachometer. Obtain the specified voltage

cranking cycle. Overheating, caused by excessive

(23.0 volts) by varying the resistance unit.

cranking, will seriously damage the starter motor.

Minimum speed should be 7000 rpm.

Check the current draw on the ammeter.

a.. No-Load. (fig. 40).

Maximum current draw should be 90

amperes.

(2) If a low speed, high current condition exists,

check the armature for excessive

arching, grounds, and shorts (par. 26d).

Examine starter for armature drag. If

drag exists, check for loose pole shoe

screws (fig. 18) and tighten as necessary.

Check for armature eccentricity (par. 26d)

or faulty bearings.

(3) If a low speed, low current condition

exists, inspect the starter for faulty

connections and for poor brush contact fig.

b. LockTorque Test. DELETED

FIGURE 40. NO-LOAD TEST WIRING

DIAGRAM.

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