Normally Open Relay Means

Meaning pronunciation translations and examples.
Normally open relay means. As with so many topics that we try to simplify by associating with something we are familiar with associating electrical current flow with water flow causes a tremendous amount of misunderstandings. 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 following is a description of the four basic types of time delay relay contacts. Normally open relays default in the open position meaning that when they re not in use there is no contact between the circuits.
Normally closed nc contacts allow current through when the relay or contactor is not energized. Normally closed what does that mean and how are they used. Relays and contactors have two types of contacts each suited for different applications. Normally open no contacts allow current when the relay or contactor is energized.
Of these contact forms the following are particularly common. What is open and 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. In other words when voltage is applied to the relay contactor terminals this contact closes.
Normally open single pole single throw spst relay in figure 1 no dc voltage is applied to points a and b therefore no current flows through the coil of the relay the contact stays in the opened position and the fan will not be switched on because it s disconnected from the 220v. Form a contacts make contacts are normally open contacts. Before we get into what normally open and normally closed are let s clarify what open and closed mean. Normally open switch contacts are in an open state at rest.