Sunday, September 6, 2015

What is Normally Open Switch And How it's Works

I published 2 post about power wiring / 3 phase wiring and in both post i talked about normally open switch and i used it in my diagrams. There will be many peoples how  don't know about that what is a normally open switch or what is NO push button switch and how its works.
To make these question off, i am gonna to write this post and i  disuse only normally open switch in this post which we better known with his short name NO which mean normal open switch . However my next post will be about the Normally close switch or NC push button.

What is Normally open switch and How it's works

This switch is momentary switch which is internally open electric circuit in normal state just like doorbell switch or we can said that doorbell switch is a good example of normal open switch. When ever we push this switch, it make contact of electric supply or make a close electric circuit. We can also called normally open contact switch.
There are some images of normal open push button switch and it's symbol for better understanding.

normally open switch symbol
Normal open push button switches and symbol

Uses of Normally open switch / NO push button switch

We can use it for many things where we required a NO push button switch but big use of this switch is in power wiring / 3 phase wiring where we use these switches for magnetic condactor to switch on and off the contactor. We use these switches in power electrical panel board and also we use in power factor improvement electrical panel, in short we can use it for any thing where we required.


The reason of this post publishing is only that i want to learn student clearly and understand every thing about electrical technology because i am also a student. I hope now your concept will be clear about the normally open switch and it's  working and uses.


  1. bhai mere ko help karo na. .panel board se moter tak ka diagram

    1. IN SHA ALLAL jald hea mea post karo ga. mean ne it diagram post kya howa hai, app website par deak sakte hai

  2. Please show me step by step processes in connecting DOL starter to 3phase motir