Components of a Contactor: 9 Parts Explained Technically!

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.

Components of a Contactor

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.

5. Armature

The armature connects the switching part to the mechanical action of the electromagnetic part.

6. Core

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.

In summary, the construction of a contactor is a simple yet precise process that requires only a few components to function efficiently. The terminal bar, moving contact, fixed contact, operating coil, armature, core, coil terminals, arc chute and shading coil all work together to make the contactor operate effectively. The terminal bar acts as a connection point, while the moving contact physically moves to complete the circuit. The fixed contact is stationary and the operating coil generates magnetic flux to move the armature. The core provides a body for the coil, and the coil terminals connect the energy to the coil. The arc chute and shading coil work to extinguish the electric arc and prevent chatter, respectively. Understanding these components’ roles in a contactor is essential in designing and building an efficient and reliable contactor system.

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