AC contactor working principle and internal structure explanation

The AC contactor is an electromagnetic AC contactor with normally open main contacts, three poles, and air as the arc extinguishing medium. Its components include: coil, short circuit ring, static iron core, moving iron core, moving contact, static contact, auxiliary normally open contact, auxiliary normally closed contact, pressure spring piece, reaction spring, buffer spring, arc extinguishing Cover and other original components, AC contactors have CJO, CJIO, CJ12 and other series products.
Electromagnetic system: It includes a coil, a static iron core and a moving iron core (also known as an armature).
Contact system: It includes main contacts and auxiliary contacts. The main contact allows a large current to pass through and cuts off the main circuit. Usually, the maximum current (namely the rated current) allowed by the main contact is used as one of the technical parameters of the contactor. Auxiliary contacts only allow a small current to pass, and are generally connected to the control circuit when used.
The main contacts of the AC contactor are generally normally open contacts, and the auxiliary contacts are normally open or normally closed. A contactor with a smaller rated current has four auxiliary contacts; a contactor with a larger rated current has six auxiliary contacts. The three main contacts of the CJ10-20 contactor are normally open; it has four auxiliary contacts, two normally open and two normally closed.
The so-called normally open and normally closed refers to the state of the contact before the electromagnetic system is not energized. Normally open contact, also known as moving contact, normally closed contact means that when the coil is not energized, its moving and static contacts are closed:. After the coil is energized, it is disconnected, so the normally closed contact is also called a dynamic contact.
Arc extinguishing device The use of the arc extinguishing device is to quickly cut off the arc when the main contact is opened. It can be regarded as a large current. If it is not cut off quickly, the main contact singeing and welding will occur, so the AC Contactors generally have arc extinguishing devices. For AC contactors with larger capacity, arc extinguishing grids are often used to prevent arcing.
The working principle structure of the AC contactor is shown in the figure on the right. When the coil is energized, the iron core is magnetized, attracting the armature to move downward, so that the normally closed contact is disconnected and the normally open contact is closed. When the coil is powered off, the magnetic force disappears, and under the action of the reaction force spring, the armature returns to its original position, even if the contacts return to their original state.