What is the Difference Between Contactor And Relay


What is a contactor?

A contactor is a device that is for making and breaking an electrical power circuit. For example, we usually use a contactor for turning on and off an electrical motor.

What Is a Relay?

Relays are the switches which aim at closing and opening the circuits electronically as well as electromechanically. It controls the opening and closing of the circuit contacts of an electronic circuit. When the relay contact is open (NO), the relay isn’t energize with the open contact. However, if it is closed (NC), the relay isn’t energize given the closed contact. However, when energy (electricity or charge) is supplied, the states are prone to change

Difference Between Contactor And Relay:

Contactors and relays are doing the duty of breaking (NO) and opening (NC) of the circuit. Both are having electromagnetic coils; the coil voltage depends on your source.  Sometime the contactor come with additional auxiliary contacts that may be either NO or NC.



Relays 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.

Relatively smaller in size

Larger when compared to Relays

Used in circuits with lower ampacity. (Max 20A)

Used in circuits with low and higher ampacity up to 12500A

Mainly used in control and automation circuits, protection circuits and for switching small electronic circuits.

Used in the switching of motors, capacitors, lights etc.

Consists of at least two NO/NC contacts

Consists of a minimum one set of three-phase power contacts and in some cases additional auxiliary contacts are also provided.

Relays do not have an arc suppression system built-in.

Normally, contactors have in- built arc chutes for suppression.


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