TM 5-4240-5501-148PSTARTERSGear Drive 12VCHECKING THE STARTER MOTORA performance test of the starter motor may be made inthe following manner.Equipment Needed -1.A tachometer capable of reading 10,000 RPM.2.A 12 volt battery 0.3 volts.3.An ammeter capable of reading 100 amperes.Connect the starter motor, battery and ammeter asshown on the accompanying illustration. See Fig. 125.Fig. 125 - Checking Stator Motor PerformanceInsert the tachometer in the end of the starter motor andactivate the starter motor. A starter motor in goodcondition will be within the following specifications.1.Starter motor RPM 5500 minimum.2.Current draw (amperes) 60 maximum (Disregardsurge current.)If the starter motor does not perform satisfactorily, thefollowing should be checked and corrected if necessary.1.A binding or seizing condition in the starter motorbearings.2.Starter motor brushes sticking in brush holders.3.A dirty or worn armature commutator or brushes.4.A shorted, open or grounded armature or fieldcoil.DISASSEMBLY OF STARTER MOTOR(See checking starter motor drive if repair, cleaning orreplacement of drive assembly is necessary.)Remove thru bolts and commutator end cap. Thearmature, drive cap and gear drive may be removed asan assembly. See Fig. 126.Fig. 126 - Removing Thru BoltsClean all dirt accumulations from the armature, endcaps, etc. The bearings, housing and armature shouldnot be soaked in a cleaning solution. The armaturecommutator may be cleaned with a 000 sand paper. Donot use emery cloth, as emery will embed in thecommutator and cause rapid wear. If it is suspected thatthe armature or field coil is defective, a new armature orfield coil should be tried in the motor. If proper testingequipment is available, check the suspected armature orfield coil to determine if it is defective. The brushesshould be checked for poor seating, weak brush springsor dirt and oil. Check to be sure brushes are not stickingin their respective brush holders. See Fig. 127.Fig. 127 - Checking Brushes37
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