Normally Open Contact Relay

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.

Normally open contact relay.

Previous picture shows what this looks like in practice. First relay 00 has a signal and closes its contacts. One is primary coil which acts as a electromagnet on passing current through it and other one is secondary side having no and nc contacts. Normally open no contacts allow current when the relay or contactor is energized.

Normally closed nc contacts allow current through when the relay or contactor is not energized. All relays react to a signal. Of these contact forms the following are particularly common. Relays control one electrical circuit by opening and closing contacts in another circuit.

The relay has two contacts normally open no normally close nc in the figure given below you can see there are two sides of a relay. First we have the normally open timed closed notc contact. Relays are switches that open and close circuits electromechanically or electronically. Form a contacts make contacts are normally open contacts.

First two relays are defined as normally open and the other two as normally closed. When power is introduced an electromagnet pulls the first circuit into contact with the second thereby closing the circuit and allowing power to flow through. 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. In other words when voltage is applied to the relay contactor terminals this contact closes.

Normally open relays default in the open position meaning that when they re not in use there is no contact between the circuits. As relay diagrams show when a relay contact is normally open no there is an open contact when the relay is not energized. Spst relay single pole single throw relay an electromagnetic switch consist of a coil terminals 85 86 1 common terminal 30 and one normally open terminal 87 it does not have a normally closed terminal like the spdt relay but may be used in place of spdt relays in all diagrams shown on this site where terminal 87a is not used. Relays and contactors have two types of contacts each suited for different applications.

The following is a description of the four basic types of time delay relay contacts.