Normally Open Relay Contact Symbol

Changeover contact this is the changeover contact of a relay that is closed or connected with one terminal known as normally closed terminal when the relay is deactivated the other terminal.

Normally open relay contact symbol.

Rarely are these familiar examples good for learning but a 3 way switch is an excellent example of using normally open and normally closed switches. Relays and contactors have two types of contacts each suited for different applications. Normally closed nc contacts allow current through when the relay or contactor is not energized. The following is a description of the four basic types of time delay relay contacts.

The contacts open when the relay activates to break the circuit. The national association of relay manufacturers and its successor the relay and switch industry association define 23 distinct forms of electrical contact found in relays and switches. Now let s go through a real world example of normally open and normally closed contacts that we are all familiar with. Relay symbols and electromagnets.

The relay are switching devices activated by signals. It is the contact of relay that is in closed position when there is no power supplied. First we have the normally open timed closed notc contact. Time delay relay contacts must be specified not only as either normally open or normally closed but whether the delay operates in the direction of closing or in the direction of opening.

Of these contact forms the following are particularly common. Normally open no contacts allow current when the relay or contactor is energized.