The car starter motor is one of the main components of an electric car. Because the engine cannot rotate on its own, a part is needed to start the first cycle. The starter motor helps the engine start, and without the car starter motor, the engine and its components will not work.

Ⅰ. Working principle of automotive starting motor

The car starter motor is an electrical device used in the engine. Once the car engine starts running, the car starter motor is disconnected from the engine. The car starter motor is installed on the transmission housing of the engine. The starter motor and a solenoid form a starter, where the solenoid receives positive power directly from the battery and the heart current from the engine body. In order to make the engine turn, a 12-volt battery must be used to start the engine. This means that the battery must be sufficient to power the device.

The starter motor has only one function, which is to provide the engine with the first and second rotations it requires. Other than that, the car starter motor is just an additional load on the vehicle.

Ⅱ. Working principle of automotive starter

The working principle of the car starter is that when the ignition key or bottom is pressed, the transmission should be in park or neutral, and the battery voltage activates the solenoid through the starter control circuit. The starter motor is powered by the solenoid, which helps to push the starter gear forward to engage with the engine flywheel. The flywheel is mounted on the crankshaft of the engine, and when the starter motor rotates, the flywheel also rotates with the crankshaft. Once the engine starts, the system disengages from the flywheel.

It is important to note that in an automatic transmission, the starter motor can only operate when the vehicle is in park or neutral. In a manual transmission, the clutch pedal must be depressed.

When the starter motor works, there are four field windings connected from the inside of the housing. The armature is connected in series with the field coils through carbon brushes. But in some starters, the field coils are replaced by the field. There is a pinion in front of the armature with an overrunning clutch on it.

Ⅲ. Principle and composition of automotive starting motor

①Armature:

The armature is the part of the electromagnet mounted on a shaft or bearing for guidance. It consists of a laminated soft iron core in which are wrapped a number of conductor rings or windings.

②Commutator:

The commutator is the part of the shaft located at the rear of the housing on which the brushes run to conduct electricity. It consists of two plates mounted on the armature shaft which provide connections for the coils of the electromagnet.

③Brush:

The brush is the part that runs on the rear housing portion of the commutator. It rubs against the commutator and conducts electricity.

④Solenoid valve:

A solenoid features two coils of wire wrapped around a core. This solenoid acts as a switch, connecting and closing the electrical connection between the starter motor and the vehicle's battery.

⑤Plunger:

The function of the plunger in the starter motor is to push forward so that the pinion gear can engage.

⑥Fork:

The lever fork is connected to the plunger so that together they push forward to engage the pinion gear.

⑦Gear:

The pinion is a small mechanism containing gears and springs. It engages the engine immediately when it starts, by extending the gear's flywheel teeth. The flywheel is the source of the engine's rotation.

⑧Excitation coil:

The field coils consist of two or more coils connected in series and are screwed into the housing. These coils receive power from the battery and convert it into an electromagnet that rotates the armature. This creates a magnetic field around the armature.

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