Starter Basics
What happens when you turn the ignition key to start position or push the start button?
The starter solenoid is first triggered drawing back the plunger attached at one end of the shift lever, pushing out the starter drive on the opposite end of the shift lever while also engaging the starter motor turning the starter drive on the flywheel bolted to the end of the crankshaft cranking the engine and starting your engine.
Returning the key to run position after starting turns the power off to the solenoid interrupting the power to the starter motor so it stops cranking and the plunger returns to rest position disengaging the starter drive.
Starter Breakdown:
Starter Motor components & their functions:
Armature: The armature is an electromagnet mounted on a shaft made up of a laminated soft iron core wrapped with windings of copper wire connected to the
commutator.
Commutator: The commutator is a section of the armature where the Brushes make contact delivering power to the windings on the armature. The commutator is made up of two plates attached to the shaft of the armature. These plates provide the contact surface for the brushes to deliver power to the windings.
Brushes: The brushes made up of carbon run on a section of the commutator at the rear of the housing, making contact with the contacts of the commutator and conducting electricity.
Solenoid: The solenoid contains a coil of wire that are wrapped around a moveable core “Plunger”. The solenoid acts as a switch to close the electrical connection and connects the starter motor to the vehicle's battery.
Plunger: The plunger works by using the connected vehicle battery and the solenoid to push the plunger forward, which engages the starter drive.
Shift Lever: The shift lever is connected to the plunger so when the plunger is pushed forward it has a pivot point where it pushing out the starter drive on the opposite end.
Starter Drive: The starter drive is a unique combination of a one way clutched gear and springs. Once the starter is engaged the gear is extended onto the flywheel. The
drive is clutched to spin in one direction to help avoid damage from over cranking and disengagement after the engine starts.
Field Coil: The field coil consist of field coils connected in series. The field casing holds the field coils in the housing with screws to the pole shoes. The fields coil is energized creating an electromagnet that turns the armature delivering torque.
Pole Shoes: The pole shoe is a steel or iron plate positioned in the center of the field coil that also becomes magnetized by the field coil when power is applied.