How a Contactor Works

by Andrea Stein - Updated September 26, 2017
Contactor devices are used to switch circuits.

An electronic circuit is composed of electronic components connected via conductive wires which enable the flow of electric currents. A contactor is used to switch circuits.


A contactor is an electrically controlled switching device used for switching a circuit, which involves interrupting or diverting a circuit from one conductor to another. Contactor applications include lighting, heating, electrical motors and other electrical loads.


Contactors connect directly with high-current load devices and contain an electromagnet. Current passes through the electromagnet, generating a magnetic field and attracting the moving core of the contactor. The coil contained in the electromagnet draws in current until the contactor’s core is pulled into the coil. When current stops flowing, the contactor core is de-energized, and gravity pushes the core back to its original position.

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Contactors range in size from several feet long to a devices that can fit in a human hand. They may contain breaking circuits ranging from several amps to thousands of amps and numerous kilovolts.


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