System Overview

System overview

General




This document describes the principle design and function of a starter motor, regardless of the make.
The starter motor (6/25) cranks the engine to make starting possible. The starter motor is located on the transmission side of the engine block. The exact location depends on engine type. A solenoid causes a pinion to mesh with the crown wheel on the engine's flywheel/carrier. When the engine has started and engine speed exceeds starter motor speed, the pinion disengages. This prevents overcranking of the starter motor.
This type of starter motor is equipped with permanent magnets instead of field winding (does not apply to V8 engines, which have field winding).
The starter motor gives the greatest torque at low rpm at the same time as the voltage current through the starter motor is greatest.

Note! The engagement time for the starter motor must not exceed 20-30 seconds. Longer engagement time results in the starter motor overheating and becoming damaged.

A starter motor relay (2/35) controls the starter motor solenoid. The starter motor relay is controlled by the engine control module (ECM).