The contactor has a simple construction. It consists of very few components. The contactor consists of the following parts: Terminal bar, moving contact, fixed contact, operating coil, armature, core, coil terminals, arc chute, and shading coil.
1. Terminal bar
The terminal bar is a connection point at the input, output, or intermediate point of a device, or a point at which a voltage is to be applied.
2. Moving contact
Moving contact is the portion that moves physically under variable operating conditions. It moves after the energization or de-energization of the coil.
3. Fixed contact
Fixed contact is the stationary contact in a contactor. After the coil energization moving contacts touch the fixed contacts.
4. Operating coil
The coil is a long conductor or group of conductors wound into a tight helical package, often in several layers on a cylindrical form. This takes advantage of the resulting concentration of magnetic flux, maximizing the inductance that can be obtained in a component of limited physical size. Further increases in inductance can be realized by the use of ferromagnetic core materials.
The armature connects the switching part to the mechanical action of the electromagnetic part.
The core is the body or form on which a coil is wound. It can be made of ferromagnetic or dielectric material. The properties depend on the application.
7. Coil terminals
Coil terminals are the connection points that connect the energy to the magnetic coil. Many contactor manufacturers use the designations A1 and A2 for coil terminals.
8. Arc chute
An Arc chute is a set of metal plates that are arranged in parallel and mutually insulated from each other, which can safely extinguish an electric arc inside the contactor.
9. Shading coil
The shading coil is a coil used in a contactor to prevent chatter.