An electro mechanical manufacturing company makes industrial control circuits with several basic components, and two of the most important parts are contractors and relays. Both work on principles of electromagnetic energy. However, there are important differences to understand if you want to know about motor control.
What is a Contactor?
A contactor performs switching duties remotely. It works on a simple principle of electromagnetic energy. When you pass electricity through a coil of wire, it creates a magnet. Magnetic energy pulls metal contacts together. The contacts are connected to wires, and when they touch, a circuit is completed.
The Electro mechanical manufacturing company dates back hundreds of years. In fact, 19th Century telegraph systems worked with contactors. Someone depressed a telegraph key in Boston and it opened and closed contactor points in New York. How was this possible? Each time the sender telegraph key was depressed, it sent an electrical signal to a coil of wire on the receiver telegraph. The coil of wire was energized and pulled down the telegraph key holding it in position. As soon as the sender let off the key, the receiver key released because it was no longer magnetized. By producing long or short delays in series, it created words through Morse code.
What are Relays?
The basic difference between contactors and relays is current. For example, a typical contactor may switch 240 volts of power to an HVAC system compressor. A relay may switch 120 volts of power within a control circuit panel.
An electro mechanical manufacturing company makes two types of relays. Some are protective. They monitor a system for current overload and then send a signal to a circuit breaker or switch. A control relay may receive a signal from a thermostat and relay it to a contactor on a heating or cooling application.