What is the working principle and schematic diagram of contactor?

The working principle of the contactor is that when the contactor coil is energized, the coil current will generate a magnetic field, and the generated magnetic field will make the static iron core generate electromagnetic attraction to attract the moving iron core, and drive the AC contactor to move, so that the normally closed contact is opened and the normally open contact is closed, which are linked.

When the coil is powered off, the electromagnetic attraction disappears, and the armature trips under the action of the trip spring, so that the contacts are reset, the normally open contacts are disconnected, and the normally closed contacts are closed. The working principle of DC contactor is somewhat similar to that of temperature switch.

AC contactor uses main contact to control the circuit and auxiliary contact to conduct the control loop. The main contact is usually a normally open contact, and the auxiliary contact usually has two pairs of normally open contacts and normally closed contacts. Small contactors are often used as intermediate relays to work with the main circuit.

The contact of AC contactor is made of silver-tungsten alloy, which has good conductivity and high temperature ablation resistance.

The schematic diagram is as follows:

The extended data is divided into DC contactor and AC contactor according to the form of main contact connection loop.

According to the operating mechanism, it is divided into electromagnetic contactor and permanent magnet contactor.

Permanent magnet AC contactor is a kind of micro-power contactor, which is formed by using the same polarity of magnetic poles to repel each other and replacing the traditional electromagnet drive mechanism with permanent magnet drive mechanism. Domestic mature product models are CJ20J, NSFC 1, NSFC2, NSFC3, NSFC4, NSFC5, NSFC 12, NSFC 19, CJ40J and NSFMR.

Dc contactor:

The overall development trend of contactors will be towards long life, high reliability, multifunction, environmental protection, multi-specification, intelligence and communication.

References:

Baidu encyclopedia-contactor