Is a relay the same as a contactor?

Is a relay the same as a contactor?

Contactors and relays have the same task of switching a circuit. If you look from the perspective of the application, you would have seen contactors in control panels of industrial engines or other heavy loads. While relays are used in low voltage applications such as switching an LED or a fluorescent tube, or even operating a circuit breaker.

Both are electromagnetic switches and work on similar principles. The difference arises from the application perspective. Contactors are used to switch high voltage while relays are used to switch low voltage.

Difference between a contactor and a relay

  • Relay is a device with typically electromagnetically controlled contacts that are actuated by electrical signals in one circuit to control the current or supply it in another circuit. So it usually has a magnetic coil, few contacts, which can be one or more contact pairs. The contacts can be normally open (normally open), normally closed (normally closed) or changeover.
  • A contactor is a type of relay in which a small current in a circuit controls a much larger current in the circuit. The power level in the relay circuit can be as low as 12/24 VDC (or AC) for the coil, while the main circuit can be single phase 230V or three-phase 440V.
  • Contacts can carry currents at these voltages. The coil can also be powered by an auxiliary circuit from the same input supply by designing a control circuit.
  • Electronic solid-state contactors that replace coils with electronic semiconductor circuits are available today, and contacts are also available in the form of semiconductor switches.

Relay vs Contactor

In Short,

Relay – A device used to operate contacts in a circuit by changing the conditions in the same circuit or in one or more associated circuits

Contactor – A device for repeatedly making and breaking a circuit under normal conditions

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