Normally Open Contactor Symbol

The given symbol indicates a normally open contact.

Normally open contactor symbol.

Auxilliary contacts symbols for use in electrical pneumatic and hydraulic schematic diagrams. It is the contact of relay that is in closed position when there is no power supplied. 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 is open known as normally open terminal. Relays and contactors have two types of contacts each suited for different applications.

To avoid confusion it is common practice to draw one set of nc overload contacts and mark these contacts all overloads ols. Normally open no contacts allow current when the relay or contactor is energized. The lamp will energize only if someone presses the switch holding its normally open contacts in the closed position normally open switch contacts are sometimes referred to in the electrical industry as form a contacts. Available in svg png jpg dxf dwg formats.

In other words when voltage is applied to the relay contactor terminals this contact closes. The relay are switching devices activated by signals. When the relay is energized the contacts open turning the light off. Normally closed contact in the following illustration when the relay is de energized the example normally closed contacts are shown as closed and are not highlighted.

Normally closed overload contacts. Now let s go through a real world example of normally open and normally closed contacts that we are all familiar with. 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. Normally closed nc contacts allow current through when the relay or contactor is not energized.

The contacts open when the relay activates to break the circuit. A complete path of current exists at this time and the light is on. This symbol is used to indicate normally close contact. Some of the most common and widely used symbols are given below 1.

Anywhere from 1 to 3 nc overload contacts are shown between the starter and l2 in all line diagrams. We can tell this switch is a normally open no switch because it is drawn in an open position. Relay symbols and electromagnets.