The solenoid switch on a starter motor plays a crucial role in engaging the starter motor with the vehicle's flywheel, allowing the engine to start. It acts as an electrical switch that controls the flow of high-current electricity from the vehicle's battery to the starter motor. Here's how the solenoid switch functions:
1. Activation: When the ignition key is turned to the "start" position, it sends an electrical signal to the solenoid switch.
2. Electrical Connection: Upon receiving the signal, the solenoid switch closes an internal electrical circuit, completing the path between the battery and the starter motor. This allows the high-current electricity from the battery to flow through the solenoid switch.
3. Engagement: The solenoid switch uses the electrical energy to activate a plunger or lever mechanism. This mechanism physically moves a gear called the "bendix gear" or "starter drive" towards the vehicle's flywheel.
4. Flywheel Engagement: The bendix gear engages with the teeth of the flywheel, which is connected to the engine's crankshaft. This engagement creates a mechanical connection between the starter motor and the engine.
5. Starter Motor Activation: As the bendix gear engages with the flywheel, it also completes a secondary electrical circuit within the solenoid switch. This circuit provides power directly to the starter motor, causing it to spin.
6. Engine Cranking: The spinning of the starter motor rotates the engine's flywheel, which in turn initiates the engine's combustion process. The engine then starts running on its own power.
7. Disengagement: When the ignition key is released, the solenoid switch deactivates, breaking the electrical circuit and retracting the bendix gear. This disengages the starter motor from the flywheel, preventing it from continuing to spin unnecessarily.
In summary, the solenoid switch on a starter motor serves as an intermediary between the vehicle's battery, starter motor, and ignition system. It facilitates the flow of high-current electricity to engage the starter motor with the engine's flywheel, allowing the engine to start.
