Contactor working principle

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Guide: A contactor is an automatic control device that relies on the action of electromagnetic force to close or break its main contacts to frequently turn on or off the main circuit with load. Then the question is coming, how does it work? This article will launch a round of offensive against this issue~~

First, the working principle of the contactor - - Introduction

A contactor is an electrical appliance in an industrial power that uses a coil to flow a current to generate a magnetic field, so that the contacts are closed, thereby controlling the load. It has been widely used in electrical engineering because it can quickly cut off the main circuit and can frequently turn on devices with large current control circuits.

Second, the working principle of the contactor - - classification

The contactor can be divided into a DC contactor and an AC contactor in the form of a main contact connection circuit. Among them, the DC contactor adopts a modular design, and strives to complete customer requirements with a minimum of parts, such as the number of contacts required, the form of contacts, and the like. The contactor voltage of the DC contactor is high, and the horizontal magnetic field is used for arc extinguishing. It is suitable for program-controlled power supply, uninterruptible power supply system, engineering machinery system, etc.

The contactor can be divided into an electromagnetic contactor and a permanent magnet contactor according to the operating mechanism. Among them, the permanent magnet contactor utilizes the same polarity repulsive of the magnetic pole, and is a kind of micro power contactor formed by using a permanent magnet driving mechanism instead of the traditional electromagnet driving mechanism. At present, there are many such kinds in the country. Mature products such as CJ20J, NSFC1, NSFC2, etc.

Third, the working principle of the contactor - - structure

The AC contactor mainly consists of four parts: the electromagnetic system, the contact system, the arc extinguishing device and other accessories. The electromagnetic system comprises an attracting coil, a static iron core and a moving iron core; the contact system and the moving iron core are connected together and mainly comprise three sets of main contacts and one set of two normally open and normally closed auxiliary contacts; The arc device is used to quickly cut off the power supply to avoid burning the main contacts, and is often installed in a large-capacity AC contactor; in addition to the above three parts, the AC contactor also includes an insulating casing, various springs, a transmission, and wiring. Accessories such as columns.

Fourth, the working principle of the contactor

When the coil is energized, the static iron core generates electromagnetic attraction, so that the moving iron core is sucked, and then the three moving contacts of the contact system are driven to operate, the main contact is closed, the auxiliary normally closed contact is opened, and the auxiliary normally open contact is activated. The point is closed and the power is turned on.

When the coil is de-energized, the electromagnetic attraction of the static iron core disappears, and the reaction force of the spring separates the moving iron core from the static iron core, and the three movable contact pieces of the contact system act to open the main contact and assist the normally closed contact. Closed, the auxiliary normally open contact is disconnected, and the power is turned off.

Contactor working principle