Construction and Working Principle of Automotive Starter

25 Aug 2023
Construction and Working Principle of Automotive Starter
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Construction and Working Principle of Automotive Starter

The construction and working principle of an automotive starter are crucial to understand how it functions in starting the car's engine. Here's a brief explanation:

Construction of Automotive Starter:

1️⃣  Armature: 

The armature is a cylindrical core made of steel laminations with slots for windings. It rotates inside the starter housing and is connected to the engine's crankshaft through the pinion gear.

2️⃣  Field Coils: 

The field coils are electromagnets mounted around the armature. They create a magnetic field when current flows through them.

3️⃣  Solenoid: 

The solenoid is an electromagnetic switch mounted on top of the starter. It consists of a coil of wire and a plunger. When activated, the plunger extends, engaging the starter's drive gear (pinion gear) with the engine's flywheel.

4️⃣  Drive Gear (Pinion Gear): 

The drive gear is a small gear mounted on the end of the armature shaft. It meshes with the engine's flywheel to turn the crankshaft during the starting process.

Working Principle of Automotive Starter:

1️⃣  Activation: 

When the driver turns the ignition key to the ''start'' position, an electrical current is sent to the starter solenoid. The solenoid coil becomes magnetized, pulling the plunger, which engages the drive gear with the flywheel.

2️⃣  Electromagnetic Field: 

Simultaneously, the electrical current flows through the field coils around the armature, creating a powerful magnetic field. This magnetic field causes the armature to rotate rapidly.

3️⃣  Mechanical Energy: 

As the armature rotates, the drive gear turns the engine's flywheel. This action transfers mechanical energy to the engine, which starts the combustion process.

4️⃣  Engine Ignition: 

Once the engine starts running and reaches sufficient RPM, the ignition system takes over, and the starter disengages from the flywheel automatically.

5️⃣  Return to Rest Position: 

When the ignition key is released, the electrical current to the starter solenoid is interrupted, and the plunger returns to its rest position. The drive gear disengages from the flywheel, stopping the starter's operation.

The construction and working principle of the automotive starter are designed to provide the necessary torque and rotational force to start the engine effectively. Once the engine is running, the starter disengages to avoid damage and unnecessary power consumption.


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