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What to Consider When Selecting a Contactor

by Joshua Stinson

A contactor is a switch that is controlled electronically, which is used for switching electrical power circuits. The most significant role of it is to distort over the power supply of electrical power circuits by making or breaking the flow of electric current lines. It is regularly used to control heating, lighting motor loads. There is variation between contactors and relays because they the ability to switch higher currents and voltage. For you to correctly select the appropriate one, you can check on Dc contactor high current for more details.

They are mostly used in areas where higher current capacity is required. They can easily be field mounted. From this extract, we are going to discuss the factors to consider when selecting a contractor.

Factors to Consider When Selecting a Contactor.

First, understand these devices differ from specifications based on the application needs, so it is significant to look for this crucial point while selecting it for your application, the coil, economizer circuit, and auxiliary contact.


The most common electrical component is the electromagnetic coil, which has another name called as the inductor. Its primary function is to produce an inductance to an electrical circuit. That is the tendency of an electrical conductor to deviate a change in the electric current flowing through it. The most crucial point to be noted down is the type of operation. Because if you prefer an ac operation, you will have to look for a correct supply frequency. In the electromagnetic core is build of soft laminated iron to reduce eddy current losses

If it is a dc operation, you will have to check for a lower power consumption alternative. The coil is used to energize the contactor to switch the primary contacts on and off. In dc, the electromagnetic core is made up of a solid soft ironic base since there is no risk in eddy current loss.

Economizer Circuit

It is used to reduce the power consumption of the coil. Due to its efficiency and reliability, it supplies high current during pickup and later provides average power to keep the contacts closed. They must all have an economizer circuit.

Auxiliary Contact Selection

The contacts are for controlling and signaling the circuit application. The standard quantity of opening (N/O) and closing (N/C) of communication. These contacts are not necessarily ranked at the same current rating as the poles. This information is very vital when selecting the right contractor for the application. It would be best to consider these other factors like environment, ambient temperature, modular design, coil surge suppressors, latching, overload.

Main Pole Selection

Consists of the current-carrying part of the inductor, that has the number of normally open and normal close, switching current ratings and ac or dc voltage. The unit category is required of AC-1, AC-2, DC 21, which is based on the type of resistive load.


The primary operation of an inductor is the same as that of a relay, but contactor contacts can receive much more currents than the relay. To have the safety required, one must consider the above key points to select the best for your application. They are categorized load, current, and power rating.




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