Power Contactor Working Principle

Unlike general purpose relays contactors are designed to be directly connected to high current load devices.

Power contactor working principle.

Contactors typically have multiple contacts and those contacts are usually but not always normally open so that power to the load is shut off when the coil is de energized. Power contactors can make carry and break the current. A contactor is typically controlled by a circuit which has a much lower power level than the switched circuit such as a 24 volt coil electromagnet controlling a 230 volt motor switch. A contactor really has only two basic parts.

These contacts are connected to the contact springs. Perhaps the most common industrial use for contactors is the control of electric motors. Low voltage contactor is an electrically controlled switch used for switching an electrical power circuit similar to a relay except with higher current ratings. Contactor is in fact an electromechanical switch.

The current flowing through the contactor energizes the electromagnet. It consists of a coil and two separate laminated cores one fixed and another moving making an electromagnetic system as shown in below image. The operating principle of the contactor is quite simple. The energized electromagnet then creates a magnetic field.

This causes the core of the contactor to move the armature. The power contacts gains the power for the contactor and the auxiliary contacts is used to bring a loop with the rest of the rest of the devices it is attached to. Working principle of contactors an electromagnetic field is generated whenever current flows where the moving coils attract each other. The contact part of the contactor includes the power contacts as well as the auxiliary contacts.

A large amount of current is drawn initially by an electromagnetic coil. Heat can destroy either of them so take a good look at both. A contactor is controlled by a circuit which has a much lower power level than the switched circuit. The contacts transmit the current from the source to the load.

The coil energizes the contactor moving the contacts into position. The top three contacts switch the respective phases of the incoming 3 phase ac power typically at least 480 volts for motors 1 horsepower or greater. The contacts and the coil. On supplying definite voltage to the coil the moving core gets attracted towards the fixed core closing the contactor.