Normally Open Relay Contact

Normally open no contacts allow current when the relay or contactor is energized.

Normally open relay contact.

Normally open contacts would represent relay contacts that would perform a connection upon receipt of a signal. 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. The circuit is connected when the relay is inactive. Form a contacts make contacts are normally open contacts.

In other words when voltage is applied to the relay contactor terminals this contact closes. When a relay contact is normally closed nc there is a closed contact when the relay is not energized. Normally open no contacts connect the circuit when the relay is activated. Unlike open contacts with normally closed contacts signal will interrupt a contact or turn a relay off.

The circuit is disconnected when the relay is inactive. When current is applied to its coil the generated magnetic field switches the armature and closes the contact so you can say that it turned on the load fan light bulb etc. When voltage is applied this contact opens and interrupts current. Normally open relays default in the open position meaning that when they re not in use there is no contact between the circuits.

A form b would mean the contacts are normally closed when the coil of the relay is not energized or the there is no magnetic field nearby in a reed switch. When the energizing force is present the contact will close. If it is a switch then it is off. If it is a high limit such as a temperature alarm then the current temperature is below the limit.

Normally closed nc contacts disconnect the circuit when the relay is activated. The no normally open spst single pole single throw relay has an opened circuit state when no current is applied to its coil so basically it disconnects the power to the load in the inactive state. If when a relay coil has 0 volts two contacts make a. This is simply the state that the contact is in when something else is not affecting it.

If it is a relay then it is not energized. As relay diagrams show when a relay contact is normally open no there is an open contact when the relay is not energized. A form c would. The contacts are open when the energizing force magnet or relay solenoid is not present.

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. Normally closed nc contacts allow current through when the relay or contactor is not energized. Of these contact forms the following are particularly common. Normally open is a contact.