Relay vs. Contactor: Key Differences Explained

This article explores the differences between relays and contactors, two essential electromechanical devices used for switching electrical circuits. Let’s delve into what distinguishes them.

What is a Relay?

• A relay is an electrically controlled switch that opens and closes contacts to control other devices within the same or a different electrical circuit.

• Relays are typically employed in circuits with lower current capacity, generally up to a maximum of 20A.

• They are generally smaller in size compared to contactors.

• Relays usually possess at least two normally open (NO) or normally closed (NC) contacts.

• Relays find applications in various circuits, including control circuits, automation circuits, protection circuits, and switching circuits.

What is a Contactor?

• A contactor is also a specialized type of relay, specifically designed for switching electrical circuits ON and OFF.

• Contactors are used to handle the switching of high currents, potentially up to 12500A.

• They often house a set of 3-phase power contacts. Some contactors also include auxiliary contacts for additional functionality.

• Arc suppression mechanisms are typically integrated within contactors to handle the arcing that can occur when switching high currents.

• Contactors are primarily used in switching applications involving motors, lights, and capacitors that draw substantial currents.

Relay vs. Contactor: Key Differences

The following table highlights the main differences between relays and contactors: