What is the difference between contacor and relay?

Relay

Single phase application

Consist of a COIL,NO,NC and Common

When Coil get energized common switches from NC to NO

Thus O/P connected with NO works.

relay

Contactor

Three phase application

Consist of a COIL and 3 NO

When coil get energized 3 PHASES (R, Y and B) will switch to o/p.

contactor


What is NC contact ?

Normally Closed contact - Basically normally closed switching is used were it requires to break or OFF a circuit.

What is NO contact ?

Normally Open Contact - Basically normally open switching is used were it required to ON a circuit.