What type of voltage is used to energize the coil on the contactor?

24 volts
In residential applications, a voltage of 24 volts is used to energize or turn on the contactor. In commercial applications, 120 volts or 24o volts can also be used to energize the contactor.

What happens when the contactor coil is de-energized?

When the contactor coil is de-energized, gravity or a spring returns the electromagnet core to its initial position and opens the contacts. For contactors energized with alternating current, a small part of the core is surrounded with a shading coil, which slightly delays the magnetic flux in the core.

What causes a contactor to spark?

Your contactor will start failing when the electrical contacts wear down. So, the energy that’s supposed to flow through the contacts dissipates elsewhere, producing arcs. These are bright orange or bluish-white sparks of electric discharge that appear in a split-second.

What is the proper procedure for checking the coil of a contactor or relay?

What is the proper procedure for checking the coil of a contactor or relay? The coil of a contactor or relay needs to be disassembled because the contacts are usually hidden. Once the contacts are visible, use the leads of an ohmmeter to measure across the coil by touching both contacts.

What causes coil chatter?

The coil heats up due to resistive heating of the wire, resistive heating in the shading coil, eddy-current losses in the magnetic circuit, hysteresis losses and contact current heating internal relay components. This will turn the relay on and off very rapidly, causing the contacts to chatter.

What causes a contactor coil to burn out?

Reason for coil burns: Coil may burn when the voltage applied to the contactor coil ends is lower or higher than normal. In addition, dust and foreign bodies in the air gap facilitate this. To prevent coil burning, the coil must be fed at the voltage and current values specified in the catalog.

Can a relay be used to switch the coil current on/off?

So long as the relay can be actuated by the control signal, and its contacts are capable of handling the actuating currents required by the contactor, there is no reason that a relay can’t be used to switch the coil current on and off in a contactor. The contactor, then, would switch current for a motor or other high-current device.

What is the difference between 120 volt and 120 volt contactors?

These voltages must be electrically isolated from the standard 120 volts AC. Contactors are used to provide this isolation. Contactors use 120 volt standard power to energize a magnetic coil, which causes a set of internal contacts to close and provide higher power to the equipment.

What is the difference between a relay and a magnetic contactor?

Relays are auxiliary contactors whereas magnetic contactors are power contactors. Magnetic contactors can safely conduct currents in hundreds of amperes whereas relays usually support current under 10 Amps. So basically for higher currents what we do is, we don’t directly control our contactor.

Why do electricians use contactors to increase voltage?

Many large pieces of equipment require a high voltage current to operate. The standard current in a home is only 120 volts AC, so electricians use a contactor to increase the current.