How does a relay work? | Normally Open | Normally Closed | Steps towards learning Automation - 02

In this episode, we will see construction and working of relays and the different types of relays such as Normally Open and Normally Closed.

It's relatively easy for anyone with an understanding of relay-type control wiring to program PLCs with little guidance.

When current runs through the control circuit and energizes the coil, it creates a small magnetic field which pulls the arm of the switch towards the coil and completes the second circuit. Thus, the light glows. When the electromagnet is not energized, the spring pulls the armature away and the circuit is not complete. In that case, the light is off. These parts are safely held with the help of a spring.

Now, when you use relays, you have to decide whether it should work as normally open or normally closed or in short active high or active low respectively. Often they are referred to as examine if closed (XIC) and examine if open (XIO). Normally open or normally closed relays depend upon the configuration of armature.