When a voltage is applied to the coil, a current passes through it and this creates a magnetic circuit which includes the core, armature and the yoke.
The core attracts the armature, which pivots and presses the push rod against the common contact, breaking the electrical connection with one contact and making the electrical connection with the other contact. When the voltage is removed from the coil the magnetic attraction of the armature to the core ceases.
A spring then returns the contacts, pushrod and armature to the initial position. In this example, the common contact also acts as the spring, but in other relays, a separate spring is employed.
The above animation shows that when we apply a voltage to the relay coil, the Relay contacts will change.
For example the Normally Open (NO) becomes Normally Closed (NC) and similarly the Normally Closed (NC ) becomes Normally Open (NO). When we remove the applied voltage to the relay coil then the relay contacts again comes into default state.
Design a relay (CR1) circuit which controls two lamps, one is Red lamp (R) and another is Green Lamp (G). These lamps will be controlled by using a single switch (S).
When switch is pressed then Red lamp will be ON and Green lamp will be ON during switch de-energised state.
If you liked this article, then please subscribe to our YouTube Channel for PLC and SCADA video tutorials.
You can also follow us on Facebook and Twitter to receive daily updates.
Read Next:
Switch Types and Common Terminology
Why we use NAMUR Output Sensor?
Pressure Switch to control two lamps
In this article, a simple example will teach you the conversion from Boolean algebra to…
In this article, you will learn the PLC cooking timer example for kitchen automation using…
Learn an example PLC program to control a pump based on level sensors using ladder…
In the PLC timer application for security camera recording, when motion is detected then camera…
In this example, we will learn batch mixing with PLC ladder logic program using timer…
This PLC example on manufacturing line assembly is an intermediate-level PLC program prepared for the…
View Comments
Dear sir I need help in configuration of pid loops in Siemens s7 200 smart PLC using microwin software
Great engineering imformation. I have a question about relay schematic: when switch is pressed: Are NO relay CR1-1 has good symbol?