Introduction To The Principle/use OF Solenoid Switch

A solenoid switch, also known as a solenoid valve or an electromagnetic switch, is an electrical component that uses an electromagnetic field to control the flow of a fluid or the movement of a mechanical device. It consists of a solenoid coil and a movable plunger or valve.

When an electric current is applied to the solenoid coil, an electromagnetic field is created, which attracts the plunger or valve. This movement either opens or closes the passage for the fluid or mechanical device, depending on the design and application of the solenoid switch.

Solenoid switches are commonly used in various systems and applications. For example, in automotive applications, solenoid switches are used in starter motors, fuel injectors, and transmission systems. In industrial automation, they are used in pneumatic and hydraulic control systems to regulate the flow of fluids or control the movements of actuators and valves.

Overall, solenoid switches provide a convenient and reliable method for remotely controlling the flow of fluids or the operation of mechanical devices through the use of electrical signals.

The Application OF Electromagnetic Switch In Automobile Starter

Most of the control devices of the car starter use the electromagnetic switch to control the starter, the role of the electromagnetic switch

Working Principle OF Solemoid Switch

When the electromagnet coil is energized, electromagnetic attraction is generated, and the active iron core pushes or pulls the switch contact to close, thus connecting the controlled circuit.

Electromagnetic switches have a wide range of applications in various industries, the most common is the contactor in the industrial field. The electromagnetic switch is a control switch on the starter, which is one of the three major components of the starter (DC motor, transmission meshing mechanism, electromagnetic switch).

The working principle is that the electromagnetic suction is generated after the coil is energized, so that the moving iron core moves, so that on the one hand, the transmission meshing mechanism is pulled to make the starter pinion forward and the engine flywheel tooth ring mesh, on the other hand, the switch contact is switched on, so that the DC motor is powered on, thereby driving the engine to start.
Turn on the starting switch, the electromagnetic switch is energized, and its current path is: positive battery → terminal 1→ ammeter → fuse → starting switch → electromagnetic switch terminal 2→ suction coil → terminal 3→ Starting motor magnetic field and armature coil → holding coil → power switch base iron → power switch → negative battery terminal

At this time, because the current direction of the attracting coil and the holding coil is the same, the magnetic force is the same. Under the joint action of the magnetic force of the two coils, the moving core overcomes the spring force and moves to the right, driving the fork to push the driving gear to the flywheel. At the same time, the moving core will move the moving contact to the static contact of the terminal post 2 and 3. When the drive gear engages with the flywheel, the dynamic contact connects the static contact at the end of the terminal post 2 and 3, so that the starter passes the starting current and generates normal electromagnetic torque to start the engine. When the moving contact is connected to the static contact at the end of the terminal post 2 and 3, the suction coil is shorted, and the moving core is kept in the suction position by maintaining the magnetic force of the coil.
After the engine starts, at the moment when the starting switch is turned off, the moving contact is still in contact with the static contact position, and the coil current of the electromagnetic switch is: positive battery → terminal 2→ moving contact → terminal 1→ suction coil → holding coil → lap iron → negative battery terminal.

At this time, the suction coil and the holding coil through the opposite current, the suction coil generated the opposite direction of the holding coil magnetic flux, the magnetic force of the two coils cancel each other, the active iron core under the action of the spring force, so that the drive gear out; At the same time, the moving contact is also returned, cutting off the starter circuit, and the starter stops working.