How does a contactor switch work?

How does a contactor switch work?

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.

How many circuits can a contactor control?

Contactors can be of the three pole type, with a high ampere rating and turn on and off a large load, or an entire panel by switching the feeder on and off. Lighting contactors can also be of the multi-pole type, rated to make and break many 20/30/40 amp branch circuit loads (generally 4 – 20 circuits).

What is the reason for the use of contactor in control circuits?

Why are Contactors Used? 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 relay and 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.

How does DC contactor work?

DC contactors are electrical switching devices, similar to a relay. The contactor functions by applying a voltage to the coil, this creates a magnetic field which moves the contacts to the closed position and completes the circuit.

What is the difference between DC contactor and AC contactor?

DC contractors have a harder job, as unlike AC the voltage never goes to zero, so arcs tend to persist. DC ones need a much larger contact spacing and sometimes arc-quenching devices such as parallel capacitors or arc-deflecting electromagnets or blowers.

When would you use a contactor instead of a relay?

Contactor: It is a device which is used for repeatedly establishing and interrupting an electric circuit under normal conditions. Control Relay is more commonly used in control circuits which are single phase circuits. Contactors are typically built for switching 3-phase load.

What happens to the contactor when you turn off the AC?

The contactor is the part of the air conditioner that controls the flow of electricity into the unit. When you turn off your AC, the contactor goes up, blocking power. By the same token, every time you turn on the air conditioner, the contactor is lowered, allowing electricity to power the system.

Where do I find the contactor on my AC unit?

Once the power is turned off, walk over to the condenser unit. The side of the unit connected to the wires is where the AC’s control panel is. Use a screwdriver to remove the side cover. You’ll see several colored wires connected to a black rectangle that’s positioned vertically. That’s the contactor.

What’s the best way to test a contactor?

To test the contactor, you’ll need a multimeter (available at any hardware or big box store). Set it to the “OL” setting. Connect the multimeter to the low volt terminals on both sides of the contactor. If the contactor is working properly, the multimeter will show a reading between 5 and 20.