what is contactor
contactor is an electromechanical switch which is used to control very high power with low input voltage. it is also acts as a protection devices. it is also defined as the contactor is an electrically operated switch which is used for switching an electrical power circuit. a contactor uses contact blocks of silver-coated copper, which are forced together to make (close) or are separated to break (open) a circuit with the help of magnetic coil. Contactors are come in various capacities from (few amperes to many kilo ampere) . It comes in both ac and dc contactors. In dc contactors their operating voltage is 24vdv and in AC contactors operating voltage is 230V or 415V.it is mainly used for the switching power of motors.
contactors have mainly consists of these parts- contacts, springs, housing and a magnetic coil.
The main function of the contacts is to make or break the circuit. these are of two types:-
These are used for control the circuit. these contacts lies NO and NC contacts.
- what are NO and NC contacts
NO contacts– NO(Normally Open) contacts are the contacts are actuated when circuit is closed.
NC contacts– NC(Normally Closed) contacts are the contacts that are actuated when circuit is open.
As the name shows power contacts. These contacts are used to make or break the power circuit.
we can also called housing as the body or frame in which the whole parts are assembled. These are made of insulating materials like thermosetting plastics to prevent the risk of short circuit.
This is heart of the contactor the magnetic coil makes electromagnetic field when rated supply reached on the contacts of the coil denoted as A1 and A2.
working of contactor
when electric current passes through the coil . the coil gets energizes and start producing magnetic field. due to the magnetic field the contacts are hold together fixed contacts and moving contacts . thatswhy the current paases through the input of the contact of the contactor to the output of the contactor.
Types of contactors
There are two types of contactors:-
Single phase contactor
single phase contactors are comes with operating voltage of 230vac. These type of contactors are used for controlling purpose. These type of contactors have four contacts are two NC(Normally Closed) and two NO(Normally Open). These contactors are comes under 5Amp. Rating. these type of contactors are also called control contactor
Three phase contactor
three phase contactors are also called power contactors. Power contactors are used for switching powers. Three phase contactors comes with operating voltage of 415vac. These types of contactors are comes over the 5amp ratings. In these contactors two auxiliary contacts found one is NO and other is NC.