Normally Open Relay Contact Symbol

First we have the normally open timed closed notc contact.

Normally open relay contact symbol.

It is the contact of relay that is in closed position when there is no power supplied. Normally open no contacts allow current when the relay or contactor is energized. Relays and contactors have two types of contacts each suited for different applications. The relay are switching devices activated by signals.

Relay symbols and electromagnets. There is a common electrical connection between a contact of each pair that results in only three connection terminals. 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. Push switch push to make a push switch allows current to flow only when the button is pressed.

Normally closed nc contacts allow current through when the relay or contactor is not energized. In other words when voltage is applied to the relay contactor terminals this contact closes. On off switch spst spst single pole. This is the switch used to operate a doorbell.

The contacts open when the relay activates to break the circuit. 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. In relay logic circuits the contacts no and nc are used to indicate normally open or normally close relay circuit. Most of the time a small voltage or current is used to switch other voltages or higher currents that may be electromechanical or fully electronic type.

Form c contacts change over or transfer contacts are composed of a normally closed contact pair and a normally open contact pair that are operated by the same device. These terminals are usually labelled as normally open common and normally closed no c nc. Relay logic circuits schematic symbols. A relay logic circuit is a schematic diagram which shows various components their connections inputs as well as outputs in a particular fashion.

On delay contacts do not have a set of instantaneous contacts which means the contacts will change state immediately when the coil of the timer is energized. The following is a description of the four basic types of time delay relay contacts. Available in svg png jpg dxf dwg formats. The normally open contact is termed normally open time close notc while the normally closed contact is termed normally close timed open contact ncto.

Auxilliary contacts symbols for use in electrical pneumatic and hydraulic schematic diagrams.