What is the Difference Between Contactor and Relay?

The main difference between a contactor and a relay lies in their load capacity. Contactors are designed to handle high currents, typically above 15 amps, while relays are more suitable for low to medium current loads, usually below 15 amps. Here are some key differences between contactors and relays:

1. Load Capacity: Relays are generally classified as carrying loads of 10A or less, while a contactor would be used for loads greater than 10A.
2. Open/Closed Contact Standards: A contactor joins two poles together without a common circuit between them, while a relay has a common contact that connects to a neutral position.
3. Voltage Rating: Contactors are commonly rated for up to 1000V, while relays are usually rated to only 250V.
4. Application: Contactors are typically used to switch high-voltage circuits, while relays are typically used to switch low-voltage circuits.
5. Size and Construction: Contactors are generally larger and more robust than relays due to their ability to handle high currents.
6. Safety Features: Relays have spring-loaded contacts due to their low load capacity, while contactors have load capacities greater than 10 amperes, which means that spring-loaded contacts are not commonly seen in them.

When selecting between contactors and relays for your application, you should consider factors such as the current, voltage, and type of circuit you are working with. Always consult the specifications of the items you are using to ensure compatibility and proper operation.

Comparative Table: Contactor vs Relay

The main differences between a contactor and a relay are their load capacity, contact types, application, and voltage rating. Here is a table summarizing these differences:

Contactors are designed to handle higher current capacities and are suitable for high voltage and current applications, while relays are suitable for voltage and current applications with a lower load capacity. Relays have two contacts (NO and NC) by default, and contactors are manufactured to work with only normally open contacts. Contactors are larger in size than relays and have an arc suppression system built-in, which relays do not have.