The electromagnetic switch of the automobile starter consists of an attraction coil (slightly thicker copper wire), a holding coil (slightly thicker copper wire), an iron core, a contact copper sheet, and a return spring. Its function is to energize the coil to move the iron core and send the clutch gear of the starter into the flywheel ring gear of the engine. When the clutch gear is coupled with the flywheel ring gear, the starter power is connected through the contact copper sheet, so that the starter rotates and starts the engine.

 1. The starter electromagnetic switch is on the starter motor. When starting, the electromagnetic switch generates magnetic force to push the starter gear to match the flywheel ring gear, and make the starter motor run, and the engine starts.

 2. The electromagnetic switch, as the name implies, is a switch controlled by an electromagnet, that is, a combination of an electromagnet and a switch. When the electromagnet coil is energized, it generates electromagnetic attraction, and the active iron core pushes or pulls the switch contacts to close, thereby connecting the controlled circuit. Electromagnetic switches are widely used in various industries, and the most common is the contactor in the industrial field. 

3. The electromagnetic switch is the most prone to failure of the starter, which directly affects the reliability of the engine.