What are Contactors and how they Work?

 Have you ever imagined why the PLC’s (Programmable logic controllers) or any other controlling equipment are not connected to the motors or high energy devices directly?

 

The simple answer is that those controlling equipment are very expensive therefore needs to be protected by electrical surges that may arise in that high load equipment.

The answer is to use these instruments called contactors.

The contactor helps to control a high load or higher power rated machine without causing any damages to the controlling equipment which are surge sensitive.

Let’s dive in to see how the contactors do so.

The interior of the contactor is as follows,

1.    The Coil-Which is energized by the signal in the PLC.

2.    The contacts that enable the power to flow through to the equipment.

 

 

 

When the coil is energized by the use of the PLC (Can be done through 24VDC,220VAC,400VAC) the coil induces a magnetic field which makes the contact to pull in so that the current from the three-phase connection is transmitted to the motor.

The motor and the PLC have no physical connection but the required work is done.

When the voltage from the PLC is switched off the coil is de-energized and therefore the current passing through is stopped.

This is similar to a relay but this can handle larger current and voltage capacities when compared to a normal relay.