How does a starter work

Enter the starter motor. The starter motor turns the engine over so that it can function. Within seconds, a starter motor performs five different functions so that your car can start.

The second the key is turned in the ignition the car battery is stimulated. The battery works the triggering switch. This allows the electrical energy to move from the battery to the starter solenoid. A solenoid is a coil of wire. It is shaped in a cylindrical form. The solenoid acts as a magnet when charged with electrical current. The starter solenoid is found above the starter motor. When the car is starting, the starter solenoid receives an electrical current from the battery. The current causes a pair of contacts in the solenoid to close.

This allows the transfer of a larger electrical current to the starter motor. That second current sent from the starter solenoid to the starter motor switches on the electromagnet. The pinion gear then turns the flywheel and the engine starts. As soon as the engine starts and you let go of the ignition key the solenoid allows the pinion gear to retract and disengage from the flywheel, preventing damage to the starter.

But how does the starter motor work? It's actually relatively simple - as you turn the key switch, power is sent to the ignition system to fire the spark plugs, and to a larger magnetic switch, which sends a rush of power direct from the battery to the starter. That magnetic switch is called the solenoid, and is typically bolted to the starter itself, both switching high amperage power and causing the gears to mesh.

When the electromagnet is engaged, the solenoid plunger connects the thick battery cable to windings within the starter to actually turn the electric motor, plus it pushes a rod, engaging a fork which in turn pushes a pinion gear connected to the motor to automatically engage with the flywheel.

The starter demands a huge amount of power, more than any other component on your car, which is why the first symptom of a low battery is difficult starting. If you turn the key and only hear "click, click, click, click" chances are the battery does not have enough power to turn the starter, but the solenoid is doing its job.

The starter pictured above is likely from a diesel car or truck, with the ability to crank under 24v power to overcome the greater compression ration of a diesel engine.

It can take a bit of troubleshooting to determine if you are having starter problems or battery problems or battery cable problems , but you certainly want to replace the right part to avoid wasting time and money. Because of this, making sure the battery is fully charged and all the wire connections are clean and tight is the first step if you have a car that won't crank, or cranks slowly.

There are several ways a starter can fail, but rarely does it happen all at once. If the internal mechanical parts of the starter the bearings for instance start to go bad it will take more power to turn it, until eventually it does not turn fast enough to start the engine. The brushes run on a section of the commutator at the rear of the housing, making contact with the contacts of the commutator and conducting electricity.

The solenoid contains of two coils of wire that are wrapped around a moveable core. The solenoid acts as a switch to close the electrical connection and connects the starter motor to the vehicle's battery. The plunger works by using the connected vehicle battery and the solenoid to push the plunger forward, which engages the pinion.

The lever fork is connected to the plunger so when the plunger is pushed forwards, so is the lever fork. This process then activates the pinion. The pinion is a unique combination of a gear and springs. Once the starter is engaged the gear is extended into the gearbox housing and is engaged with the flywheel.

This spins the engine to begin the combustion process. The housing holds the starter fields in the housing with screws. This can consist of two to four field coils connected in series.

Energised by the battery this converts the coils into an electromagnet which then turns the armature. When the armature coils are powered a magnetic field is created around the armature. Highlighted differences. Compare more? Add to Compare remove all. Home Starter Motors.