The composition and working principle of electronic AC contactor

Components The electronic AC contactor consists of the following parts: 　　 (1) electromagnetic system, including attraction coil, moving iron core and static iron core; 　　 (2) contact system, including three main contacts and two normally open, Two normally closed auxiliary contacts, which are connected to the moving iron core and are linked to each other; 　　 (3) Arc extinguishing device, generally AC contactors with larger capacity are equipped with arc extinguishing devices to quickly cut off the arc and avoid Burn out the main contact; 　　 (4) Insulating housing and accessories, various springs, transmission mechanisms, short-circuit rings, terminals, etc.　　Working principle　　The electronic AC contactor uses the main contact to open and close the circuit, and the auxiliary contact to execute the control command. The main contact generally only has a normally open contact, while the auxiliary contacts often have two pairs of contacts with normally open and normally closed functions. Small contactors are often used as intermediate relays to cooperate with the main circuit.　　The power of its action comes from an AC electromagnet. The electromagnet is made up of two 'mountain'-shaped thin silicon steel sheets, one of which is fixed, and a coil is placed on it. There are a variety of operating voltages to choose from. In order to stabilize the magnetic force, a short-circuit ring is added to the suction surface of the iron core.　　 The AC contactor relies on spring to reset after power failure. The other half is the movable iron core, the structure is the same as the fixed iron core, used to drive the main contact and auxiliary contact to open and short. The contactor above 20 amperes is equipped with an arc extinguishing cover, which uses the electromagnetic force generated when the circuit is disconnected to quickly break the arc to protect the contact.