PIPE AS 4557599 - Caterpillar

Illustration 1 g00712156
50-MT series starting motor
The 50-MT series starting motor may be ordered in the following versions: 24 volt, 32 volt and 64 volt. See the chart in Specifications, "50-MT Series Starting Motor Coverage" for a list of part numbers for starting motors that are covered in this module. The starting motor is used in order to turn the engine flywheel quickly in order to allow the engine to run. The starting motor has a solenoid assembly. When the key start switch is activated, electricity from the electrical system will cause the solenoid to move the pinion drive assembly toward the flywheel ring gear of the engine. The electrical contacts in the solenoid close the circuit between the battery and the electric starting motor just before the pinion engages the ring gear. This causes the starting motor to rotate. This type of motor “activation” is referred to as a positive shift starting motor. When the engine begins to run, the overrunning clutch of the pinion drive assembly prevents damage to the armature by breaking the mechanical connection. The pinion will stay meshed with the ring gear until the key start switch is released. A return spring in the overrunning clutch returns the clutch to the rest position.