The internal combustion engine must be rotated before it will run under its own power. The starting system is a combination of mechanical and electrical parts that work together to start the engine. The starting system is designed to change the electrical energy, which is being stored in the battery, into mechanical energy. To accomplish this conversion, a starter or cranking motor is used. The starting system includes the following components:
- Cable and wires.
- Ignition switch.
- Starter solenoid or relay.
- Starter motor.
- Starter drive and flywheel ring gear.
- Starter safety switch.
FIGURE. Major components of the starting system. The solid line represents the starting (cranking) circuit and the dashed line indicates the starter control circuit.
Components in a simplified cranking system circuit are shown. This chapter examines both this circuit and the fundamentals of electric motor operation.