Working principle of fretsaw Motor

Working principle of fretsaw Motor
Working principle of starter

The control device of automobile starter includes electromagnetic switch, starting relay and ignition starting switch lamp components, in which the electromagnetic switch is made together with the starter.
Electromagnetic switch
1. Structural features of electromagnetic switch

The electromagnetic switch is mainly composed of electromagnet mechanism and motor switch. The electromagnet mechanism is composed of a fixed core, a movable core, a suction coil and a holding coil. The fixed iron core is fixed, and the movable iron core can move axially in the copper sleeve. The front end of the movable iron core is fixed with a push rod, the front end of the push rod is installed with a switch contact plate, and the rear section of the movable iron core is connected with the shift fork with an adjusting screw and a connecting pin. A return spring is installed outside the copper sleeve to reset movable parts such as movable iron core.
2. Working principle of electromagnetic switch

When the magnetic flux direction generated by the energization of the suction coil and the holding coil is the same, their electromagnetic suction is superimposed on each other, which can attract the movable iron core to move forward until the contact pad at the front end of the push rod connects the electric switch contact and the main circuit of the potential motor.

When the magnetic flux directions generated by the energization of the suction coil and the holding coil are opposite, their electromagnetic suction counteracts each other. Under the action of the return spring, the movable parts such as the movable iron core will automatically reset, the contact pad and the contact are disconnected, and the main circuit of the motor is disconnected.
Start relay
The structure diagram of starting relay is composed of electromagnet mechanism and contact assembly. The coil is respectively connected with the ignition switch terminal and grounding terminal “e” on the housing, the fixed contact is connected with the starter terminal “s”, and the movable contact is connected with the battery terminal “bat” through the contact arm and support. The starting relay contact is a normally open contact. When the coil is energized, the relay core will generate electromagnetic force to close the contact, so as to connect the suction coil and holding coil circuit controlled by the relay.
1. Control circuit

The control circuit includes a starting relay control circuit and a starter electromagnetic switch control circuit.

The starting relay control circuit is controlled by the ignition switch, and the controlled object is the relay coil circuit. When the starting gear of the ignition switch is turned on, the current flows from the positive pole of the battery through the starter power terminal to the ammeter, and from the ammeter through the ignition switch, the relay coil returns to the negative pole of the battery. Therefore, the relay core generates strong electromagnetic suction, which is the control circuit of the starter electromagnetic switch when the relay contact is closed.
2. Main circuit

Battery positive pole → starter power terminal → electromagnetic switch → excitation winding resistance → armature winding resistance → grounding → battery negative pole, so the starter generates electromagnetic torque and starts the engine.