Relay vs Contactor-Difference between Relay and Contactor

This page compares Relay vs Contactor and mentions difference between Relay and Contactor.

What is Relay?

• The relay is controlled device which opens and closes contacts in order to effect operation of other devices in the same or another electric circuit.
• The relay is used in circuits with lower ampere capacity i.e. Max. 20A.
• They are smaller in size.
• They have at least two NO/NC contacts.
• They are used in control circuits, automation circuits, protection circuits and switching circuits.

Relay vs Contactor

What is Contactor?

• It is also special type of relay which is used to switch ON/OFF of an electric circuit.
• The contactor is used for switching of high currents which is about 12500A load.
• It houses set of 3-phase power contacts. Some contactors use additional auxiliary contacts.
• Arc suppression arrangements are available inside the contactors.
• They are mainly used for switching applications in motors, lights and capacitors draining very high currents.

Following table mentions difference between relay and contactor.

Specifications Relay Contactor
Application It is used for lighter load switching (below 5 KW). Hence it is known as light duty switch. It is used for heavier load switching. Hence it is known as heavy duty switch.
Voltage It is used for low voltage applications. It is used for high voltage applications.
Cost Cheap Expensive
Repairing It is not economical to repair. It is designed such that it can be repaired.
Main application It is used in control circuit only. It is used in both control circuit as well as power circuit.


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