Four important parts of AC contactor and its working principle
1- Arc shield, 2- Contact pressure spring sheet, 3- Main contacts, 4- Reaction spring, 5- Coil, 6- Short circuit ring, 7- Static core, 8- Spring, 9- Moving core, 10- Auxiliary normally open contact, 11- Auxiliary normally closed contact.
(1) Electromagnetic mechanism: electromagnetic mechanism is composed of coil, moving iron core (armature) and static iron core. Its function is to convert electromagnetic energy into mechanical energy, and generate electromagnetic attraction to drive contact action.
(2) Contact system: including main contacts and auxiliary contacts. The main contact is used to break the main circuit, usually three pairs of normally open contacts. Auxiliary contact is used in the control circuit, which has the function of electrical interlock, so it is also called interlock contact, usually two pairs of normally open and normally closed.
(3) Arc extinguishing device: contactor with more than 10A capacity has arc extinguishing device. For small capacity contactor, double break contact arc extinguishing, electric power arc extinguishing, phase arc plate arc separation and arc extinguishing arc of clay arc extinguishing are often used. For the large capacity contactor, the longitudinal arc extinguishing cover and the grid arc are used to extinguish the arc.
(4) Other parts: including reaction spring, buffer spring, contact pressure spring, transmission mechanism and shell, etc..
The electromagnetic contactor (cj19 magnetic contactor) works as follows: when the coil is energized, magnetic flux and electromagnetic attraction are generated in the iron core. The electromagnetic force overcomes the reaction force of the spring to cause the armature to attract and drive the contact mechanism; the normally closed contacts are opened; the normally opened contacts are closed, interlocked or connected. When the coil is out of power or the voltage at both ends of the coil is significantly lowered, the electromagnetic attraction is less than the counterforce of the spring, so that the armature is released, the contact mechanism is reset, the circuit is disconnected or the interlock is removed.