A: A car starter is a motor usually shaped like a cylinder, with a durable metal housing protecting its components. Parts of a car starter include the starter solenoid, which is a smaller cylinder attached to the motor.
The car starter has a small pinion or gear wheel on one end. When the ignition is turned on, the pinion locks with a larger gear ring mounted near the engine flywheel, which then spins to begin the combustion process. The ring gear-to-starter gear ratio is usually about 14 to 1.
While car starters can vary in design, they typically consist of the following components:
Mounted to the drive shaft, the armature is a rotating electromagnet with a soft iron core, with conductor loops or windings wrapped around it.
The commutator refers to the two plates found at the rear of the housing, where it also connects to the axle of the armature. It allows the car starter’s brushes to conduct electricity.
The starter brushes can be found at the rear of the housing, where they conduct electricity while connected to the commutator.
The plunger pushes forward when the ignition is started, closing the solenoid contacts and moving the lever fork in the same direction.
Connected to the plunger, the lever fork also moves forward when the plunger does, and this activates the pinion and allows it to engage with the engine flywheel.
Most starter motors consist of four field coils or windings, which are connected in series to the starter motor’s housing. When electricity runs through the coils, they turn into an electromagnet that then moves the armature, creating a magnetic field around it.
In vehicles with a front-engine layout, the starter is inside the engine bay, mounted low near the back of the engine. In some vehicles, the starter motor can be found bolted to the transmission.
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