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14 April 2021

Difference Between Relay and Contactor

Contactors and relay are two closely related terms leading to confusions and misinterpretations most of the time. Both of them are electrically operated switches used for control and switching of load. So here this article gives the difference between the relay and contractor to better understand this topic.

What is Relay?

Relay is a device by mean of which is one circuit are operated by a change in conditions in the same circuit or in one or more associated circuits.

What is Contactor?

A device for repeatedly establishing and interrupting an electric circuit under normal conditions.

 Difference between Relay and Contactor:

  • Relay is relatively smaller in size, while the contactor is larger when compared to relay.
  • Relay is used in circuits with lower ampacity, while the contactor is used in circuits with low and higher ampacity up to 12500A.
  • Relay are switching devices used in any control circuit for checking a condition or multiplying the number of contacts available, Contactors are switching devices used to control power flow to any load.
  • The relay consists of at least two NO/NC contacts, while the contactor consists of a minimum of one set of three-phase power contacts and in some cases, additional auxiliary contacts are also provided 
  • Relay is mainly used to control and automate circuits, protection circuits, and for switching small electronic circuits, while the contactor used in the switching motors, capacitors, lights, etc.
  • Relay does not have an arc suppression system built-in, while the contactor has arc chutes for suppression
  • Control relays are generally classified as carrying a load of 10A or less, while a contactor would be used for a load greater than 10A.
  • Relays are usually rated at only 250V, while the contactors are commonly rated for up to 1000V.
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