TM 10-4610-229-24
3-48. STARTER REPAIR (CONT)
2
Connect the batteries in series.
3
Connect ammeter between positive (+) post of battery and battery (BAT) terminal of starting motor.
4
Connect switch between battery (Bat) terminal and starter (S) terminal of starting motor.
5
Connect voltmeter between motor (M) terminal and starting motor frame.
6
Connect a lead between negative (-) post of battery and starting motor frame.
7
Connect tachometer to starter.
8
Turn switch on. Record readings from tachometer, voltmeter, and ammeter.
9
Voltage reading should be 20 volts. Amperage reading should be 70-110 amps. Tachometer reading should be
5500-9000 rpm. Test interpretation:
a
Low rpm reading and high amperage reading indicate:
(1)
Too much friction.
(2)
Shorted armature.
(3)
Grounded armature.
b
Failure to operate but high amperage reading indicates:
(1)
A direct ground in the terminal or fields.
(2)
Defective bearings.
c
Failure to operate but no amperage reading indicates:
(1)
Open field circuit.
(2)
Open armature coils.
(3)
Broken brush springs, worn brushes, high insulation between the commutator bars.
d
Low rpm reading and low amperage reading indicates:
(1)
Poor connection, defective leads, dirty commutator.
(2)
A direct ground in the terminal or fields.
(3)
Defective bearings.
10
Disconnect tachometer from starter.
11
Disconnect lead from negative (-) post of battery and starting motor frame.
12
Disconnect multimeters and switch.
13
Disconnect batteries. Disconnect carbon pile.
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