Difference Between Contactor and Relay

A contactor joins 2 poles together, without a common circuit between them, while a relay has a common contact that connects to a neutral position. Additionally, contactors are commonly rated for up to 1000V, while relays are usually rated to only 250V.

Why use a relay instead of a contactor?

Relays are switching devices used in any control circuit for checking a condition or multiplying the number of contacts available. Contactors are switching devices used to control power flow to any load. Mainly used in control and automation circuits, protection circuits and for switching small electronic circuits.

What is the function of contactor relay?

A contactor is a large relay, usually used to switch current to an electric motor or another high-power load. Large electric motors can be protected from overcurrent damage through the use of overload heaters and overload contacts.

Why would you use a contactor?

Contactors are used for high power applications. They allow a lower voltage and current to switch a much higher power circuit, so they are generally larger and more heavy-duty than control relays, enabling them to switch higher power loads on and off for many thousands of cycles (Figure 1).

What is the difference between a contactor and a starter?

A contactor is an electrically controlled switch similar to a relay. Whereas, a starter is a contactor with the addition of an overload relay. A contactor applies voltage to a contactor coil to close the contacts and to supply and interrupt power to the circuit.

What is NO and NC In Contactor?

Relays and contactors as used in Chamberlain products can be applied in two modes: normally open (NO) and normally closed (NC). ... Contactor - A magnetically-operated device, for repeatedly establishing and interrupting an electrical power circuit.

What is the working principle of contactor?

Operating Principle of a Contactor:The current passing through the contactor excites the electromagnet. The excited electromagnet produces a magnetic field, causing the contactor core to move the armature. A normally closed (NC) contact completes the circuit between the fixed contacts and the moving contacts.

What is the symbol of relay?

A single pole switch is often denoted by the letters SP, and a double pole by DP. Relays can have one, two or more poles. Throw: The number of throws on an electrical switch is the number of positions that are available. For an electromechanical relay, there are normally only one or two throws.

How a contactor is wired?

Break your circuit, L N E through your contactor. Link a permanent live and a neutral from your supply to your coil (Al + A2) then use your switch feed to your photocell from A1, and switch the wire to the switched phase of your contactor load. This should now open when light, close when dark.

What is difference between relay and circuit breaker?

The Relay is a switching and sensing device, but the Circuit breaker is an isolating or disconnecting device. Relays operate on low power input voltage. ... The Relay is used to control or select one among many circuits, whereas Circuit Breaker is one per circuit. Relay acts an electrical amplifier for discrete signal.

What would cause a contactor to burn up?

A minor increase is normally permissible as long as the nominal coil voltage is not exceeded. ... By far the most common cause of contactor coil failure is, surprisingly to many, undervoltage. There may be sufficient voltage to pull the contactor in, but not enough to keep the coil armature formers firmly "sealed".

How many types of contactors are there?

Hence, it is a very important component of the contactor. The contacts are classified as power contact, auxiliary contact, and contact spring. There are two types of power contact; stationary contact and movable contact. The material used for the contacts has stable arc resistance and high welding resistance.

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