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Gibbons jargon buster #9: What is a contactor?

It’s time for another of our straight-talking blogs explaining some of the terminology used in our industry. Today we ask “what is a contactor?”

What is a contactor?

A contactor is an electrical switch used for controlling a power circuit - similar to a relay but of higher capacity. Contactors vary significantly in size – from those small enough to hold in one hand to some which weigh many tonnes.

What is a contactor made up of?

A contactor has three main components:

  • Contacts - These carry the current.
  • Electromagnet - Also referred to as a coil, this provides the force required to close the contacts.
  • Enclosure - This is the frame that houses the contacts and electromagnet, providing protection from dust, weather and other hazards.

What are contactors used for?

Contactors are useful for many applications, including:

  • Electric motor starting
  • Lighting control
  • Heating control
  • Isolation
  • Bypass
  • Distribution

What is arcing?

An electrical arc is a luminous discharge of current which occurs when electrons jump across a gap. Lightning is a well-known natural occurrence of arcing.

In a contactor, when contacts are separated there is a risk of arcing. If arcing occurs, the severe heat generated means that contacts are likely to be damaged. Contactors are therefore designed to open and close very quickly in order to minimise the effect of arcing.

For more information on our Panel Building division, give us a call on 01621 868138 or email and we’ll get right back to you.

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