Relays and Contactors Basics – Video Tutorial

This is a relay and contactors basics video tutorial. This video shows how relay and contactors work. The relay is an electromechanical switch it works an electromagnet. There are three electrical connection on relay, they are common, normally close and normally open. There is a small contactor inside relay. Besides that, inside relay there is a coil. The coil can be supplied with 12V DC, 24V AC or 120V AC. If we connect the wire on normally close, when there is no power applied on the coil, the lamp will turn on, when the power applied on the coil, the magnet will pull the wiper down so the lamp will turn off. If we connect the wire on normally open, when there is no power on coil the lamp will turn off, when the power is applied, the magnet will pull the wiper and connected to normally open, so the lamp will turn on. Here is the video :