Starter Motor: Description and Operation

Starter

The starter motor is a 12 volt unit that has a starter solenoid mounted on the drive end housing. The starter solenoid is energized when the ignition switch is turned to the START position.

When the starter solenoid is energized, a magnetic field is created in the starter solenoid windings. The iron plunger core is drawn into the solenoid coil, and the drive lever and pin connected to the starter drive engages the flywheel ring gear. When the plunger is pulled all the way in, its contact disk closes the circuit between the battery and starter motor teed terminals. This sends current to the starter motor, and the starter drive cranks the flywheel to start the engine. When current flows to the starter motor, the solenoid pull.in coil is bypassed, and the hold-in coil keeps the starter drive engaged with the flywheel until the ignition switch is released from the START position.

The starter drive protects the starter motor from excessive speeds during the brief period before the driver releases the ignition switch from the START position.

A Park/Neutral Position (PNP) switch circuit within the Transmission Range (TR) switch senses when the gearshift lever is in the NEUTRAL (N) or PARK (P) position and completes the starter motor circuit.

The starter motor uses a planetary gear reduction system to reduce internal torque.