What does an AC contactor consist of? I think everyone already has the answer. Our article here is specially prepared for novices. Please read it patiently.
AC contactor is mainly composed of four parts:
(1) electromagnetic system, including attracting coil, moving iron core and static iron core;
Electromagnetic mechanism. It consists of coil, moving iron core (armature) and static iron core. Some contactors use a double E-type direct-acting electromagnetic mechanism in which the armature moves linearly, and some contactors use a folded electromagnetic mechanism in which the armature moves around the axis.
(2) contact system, including three pairs of main contacts and two normally open and two normally closed Auxiliary contact, which is connected with the moving iron core and linked to each other;
Contact system. Including main contacts and auxiliary contacts. The main contacts are used to make and break the main circuit, usually 3 pairs (3 poles) normally open contacts. Auxiliary contacts are used in control circuits and play an electrical interlocking role, so they are also called interlocking contacts. Generally, there are two pairs of normally open and normally closed.
(3) Arc extinguishing device, generally large-capacity AC contactors are equipped with arc extinguishing device to quickly cut off the arc and avoid burning the main contact
Arc extinguishing device. Contactors with a capacity of more than 10A have arc extinguishing devices. For contactors with small capacity, double-break contact arc extinguishing, electric power arc extinguishing, interphase arc plate arc isolation and clay arc extinguishing cover arc extinguishing are commonly used. For large-capacity contactors, arc extinguishing covers and grids are used for arc extinguishing.
(4) Insulating shell and accessories, various springs, transmission mechanisms, short-circuit rings, terminals, etc.
Other parts. Including reaction spring, buffer spring, contact pressure spring, transmission mechanism and shell, etc.
The working principle of the AC contactor: when the coil is energized, the coil current generates a magnetic field, which makes the static iron core generate electromagnetic attraction and the armature is attracted. The armature drives the contact action to close the normally closed contact. When the coil is powered off, the electromagnetic attraction disappears, the armature is released under the action of the reaction spring force, and the contacts are reset accordingly.