Difference between Contactor and Relay

Contactor vs Relay

Contactor and relay are two terms often encountered when dealing with electric circuits. Both these devices are used for similar purposes and hence people are often confused about the difference between a contactor and a relay. This article clarifies the differences between the two devices to remove any confusion once and for all.

Let us talk about the ignition system of your car. When you turn the ignition on, it is not the ignition that interacts directly with the battery of the car. Rather it activates an electric relay that passes the signal to start the car. The relay performs an important function here as heavy duty insulated wiring would be required to connect steering column to the battery if ignition were to be directly connected with the battery. But when a relay is used, lighter wiring can be used which not only helps in saving space but also increases safety of the vehicle.

A relay is a device that can be classified as electrically operated control switches and relays are either power relays or control relays depending upon their use. While power relays are called contactors, control relays are simply called relays.

When a relay is used to switch a large amount of electrical power through its circuits, it is given a new name, a Contactor. These contactors are very commonly used in industries for control of electric motors. Thus it is clear that contactor is only a special type of relay. But what are the differences between a relay and a contactor?

Difference between Contactor and Relay

• Since a contactor is required for a higher load, a relay is always cheaper than a contactor.

• A relay is normally used in appliances below 5KW, while a contactor is preferred when the appliance is heavier.

• A relay is used only in control circuit while a contactor can be used in both control and power circuits.

• In general contactors are little slower than relays

• Contactor is so designed that it can be repaired while it is not normally done in the case of relays.

  • disqus_YvUTq1HRI6

    Really good thing to learn. A long awaited answer.. Thanks Olivia