Get An Idea About The Ac Contactor’s Working Principle

By Author: Ryan
Total Articles: 14
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The electromagnetic AC contactor has three poles, a NO main contact, and air as the arc extinguishing medium. The coil, short-circuit ring, moving contact, static contact, moving iron core, auxiliary NO contact, auxiliary NC contact, pressure spring sheet, response spring, buffer spring, and arc extinguishing device are some of its components. There are original components on the cover.

A coil, a stationary iron core, and a moving iron core make up the electromagnetic system.


Contact system: Both primary and secondary contacts are present. The main contact allows a larger current to pass through while connecting and disconnecting the main circuit. The maximum current allowed by the primary contact is frequently one of the contactor's technical features.

Auxiliary contacts are normally connected to the control circuit while they are in use and are only allowed to transport extremely small currents.

While the main contacts on AC contactors are frequently NO contacts, ...
... the auxiliary connections can either be NO or NC contacts. Four auxiliary contacts are present in a contactor with a lesser rated current, whereas six auxiliary contacts are present in a contactor with a greater rated current.

The terms NO and NC describe the contacts' condition before the electromagnetic system is powered. In other words, the NO contact indicates that the coil's moving and static contacts are open while it is not electrified and that the coil is closed when it is powered.NC contact denotes that the moving and static contacts are closed when the coil is not energized, and they are disconnected when the coil is energized.

The task of the arc extinguishing device is to quickly terminate the arc when the main contact is lost. The primary contact will sing and weld if it is not stopped right away. As a result, AC contactors exhibit arc extinguishing mechanisms. Arc extinguishing grids are typically used with larger-capacity AC contactors.

The armature is moved downward when the coil is ignited, opening the usually closed contact and closing the normally open contact. When the coil is de-energized, the magnetic force is gone. The armature is brought back to its starting position by the reaction spring, and the contact assumes its starting state.

One of the most often utilized low-voltage control devices in power drag and automated control systems is the AC contactor. It serves as an executive component that connects and disconnects lines or controls the functioning of electric motors and other machinery regularly. It is made up of auxiliary contacts, bracket shells, moving and static iron cores, moving and static main contacts, arc extinguishing cover, and moving and static iron cores.

Three arc extinguishing techniques are frequently used by AC contactors: grid extinguishing, longitudinal seam extinguishing, and double-break electric arc extinguishing. It is utilized to get rid of the arc that is created when the moving and static contacts open and close. Reaction springs, buffer springs, contact pressure springs, transmission mechanisms, bases, and terminals are additional auxiliary parts of the AC contactor.

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