NC & NO contacts

[M4gery]

They are normally open when you get them at the suplly house,there job is to open when the power is cut ..
and when you close the door the button becomes live and now it is closed open the door button is dead and goes back to its normal state 'normally open'

I understand that, I am asking why they are common called NC. As you said, they are NO contacts.

I assume it is because they are part of a NC loop.

 

[LEO2854]

I understand that, I am asking why they are common called NC. As you said, they are NO contacts.

I assume it is because they are part of a NC loop.

lets say we have a coil that is powerd by normal power in a lab and you need somthing to stay on when you lose normal power,So you have a contactor that has two sets of contactors.
the first set of contactors are normally open when the coil has no power
The second set of contactors are normally closed when the coil has no power
and your em power goes through the second set of contactors.

So you have two feeds reg power feeds the coil and goes through the first set of contactors
EM power is at that sencond set of contactors that is being held open by the coil.
i hope that helps it is confusing.:-?