So to begin with, a contactor is a kind of electrical switch that is used for switching on/off an electric circuit. You will more often than not find them with the big motors that are used in huge industries for various purposes. They are used with the motors in order to protect the motor from different overload conditions.

The contactor also protects a motor incase of overcurrent in the motor. In case you were not aware then the power of the contactor is greater than the power of the circuit to which it is connected. The electric relays and switches are usually connected indirectly with the circuit whereas the contactors are attached directly to the circuit. Moreover, the devices that can handle the current rating more than 15 amps are known as contactors. They can easily suppress and control the arc produced in heavy motors and used to control the flow of the current.

Everything boils down to picking the right contactor for a motor or Servo motors, and before you do that the different parts of the motors should be first analyzed. Some things you consider before buying a contactor are the load type of the motors and the amount of current drawn for the motor.

Some of the other important parameters while choosing a contactor are:

Contact (switch) Ratings

The contact rings can be bifurcated into - maximum switching voltage and maximum switching current. So a maximum switching voltage that a switch can take is derived on the basis of the ratings of the circuit / motor on which the contactor will be used. At the same time, the maximum current rating that a contactor can bear will be selected according to the rating and not just that, but the maximum inrush current during the startup of the motor is also considered.

Coil Ratings:

They are also taken into consideration while choosing a contactor are:

• Pick-Up Voltage: It is the voltage at which all the switches will be on their operating position known as the pick-voltage. It is taken into consideration when you’re out selecting the right contactor for you.

• Rated Coil Voltage: Make sure that the voltage should be equal to the voltage of the circuit powering the coil when you are picking a contactor.

• Drop-Out Voltage: It is the voltage at which the switched of the contactor will be at an up-operated position.

• Operating Current: The current of the coil is also an important factor while selecting the contactor.

Auxiliary Contacts:

Wondering what they are used for? They are used in between the contactors and the circuits for several functionalities. While you are selecting the right contactor, auxiliary contacts MUST be considered, and they hold great value. Parameters to be considered while selecting a contactor are discussed above, but the selection of the right contactor for the motor is an ever more vital parameter and should not be missed over picking the right contactor for the motor.

Whereas the two steps while selecting the right contactor for a specific motor are:

• Gather the right information about the motor.

• Make sure that you extract the right kind of information from the right datasheet of the product.

In the end, we would like to conclude by saying that these were some of the things that you must consider before buying a contactor.