ControlElectrical WiringMotorsProtection

Important Terms and Definitions related to Motor Control and Protection

Important Terms and Definitions related to Motor Control and Protection
Below are the basic and important terms related to Three phase motor control and protection and you must know for understanding and reading the control diagrams of three phase motors. There are lots of terms but we will define the most important and related to the topic.

Click image to enlargeImportant Terms and Definitions related to Motor Control and Protection

Following are the important terms related to Motor Control and Protection

Electromagnetic Contactor
A contactor, in which the main contacts close and open through electromagnetic effect.

Electro-pneumatic Contactor
This is a contactor in which force provides for opening or closing the main contact through the electrically operated pneumatic device.

Main Circuit
Current flows from supply to the load through main circuit. This circuit is designed for closing or opening the conducting parts of the contactor.

Main Contact
When a Contactor is in Close position, then main contacts in the main circuit are responsible to carry the load current

Control Circuit
That circuit which is designed for the closing or opening operation of the contactor. This circuit is electrically energized or de-energized normally.

Auxiliary Circuit
As the name indicates, this is another circuit except main and control circuit i.e. auxiliary circuit.

Make Contact
That Control Contact, which closes when main contact closes.

Break Contact
That Control Contact, which opens when main contact closes.



  1. Ashish vegadava says:

    Thaks 4 give us motor control and protection knowledge.

  2. leonard kasambala says:

    I gain something

  3. ampalavanar sampanthar says:

    Very good article

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button

Kindly permit ads on our free website.

It appears that you are using an ad blocker. We rely on advertising to support our website, provide free information, and sustain our services. Kindly consider whitelisting our website to allow ads.