How electromechanical relay works?
Electromechanical Relay
Relay has played a vital role in factory automation. Factory automation wouldn't have succeeded without this magical instrument.It is like a switch that connects or disconnects two circuits. But instead of manual operation a relay is applied with electrical signal, which in turn connects or disconnects another circuit. Relays can be of different types like electromechanical, solid state. Electromechanical relays are frequently used.
Operating principle
employed 3 trips for switching purpose. One strip has been placed between two strips is called as common strip.
Since two strips are in contact due to spring force, that contact is called as NC (normally closed). As we know whenever we give electric supply to copper wounded coil, it gets energized and produces magnetic field.
Rightnow, oven is not getting electric supply, because supply is discontinued. Once we give supply to coil it will attract commen strip to downward direction and circuit will get completed and oven will start working.
In order to energies coil you can provide it either AC or DC supply depends on specifications of relay.
Relay acts like an isolator to PLC.
Terminals and connection
A1 terminal- 24V DC/ 230V AC
A2 terminal- 0V DC/ N AC
P (commen)- DC/ AC supply
NC (normally closed)
NO (normally open)
Coil is energized by giving supply to A1 and A2 terminals of relay. Output device to be operated either by DC or AC supply, same supply is connected to commen terminal and depending upon requirements output device is connected to either NO or NC terminals.
Application of relay
1. Industrial application- switching purpose such as solenoid coil, contactor, lamps, etc, in plc control panel.
2. Home appliances- washing machine, refrigerator.
3. OA devices- copy machine.
