Abstract
A relay is a device that makes a measurement or receives a signal that causes it to operate and to effect the operation of other equipments. A protection relay is a device that responds to abnormal conditions in an electrical power system to operate a circuit-breaker to disconnect the faulty section of the system with the minimum interruption of supply. Many designs of relay elements have been produced that are based on a few basic operating principles. The majority of electromechanical relays are in one of the following groups: induction relays; attracted-armature relays; moving-coil relays; thermal relays; and timing relays. The induction relay is based on the domestic kilowatt-hour meter, which has a metal disc free to rotate between the poles of two electromagnets. Torque is produced by the interaction of upper electromagnet flux and eddy currents induced in the disc by the lower electromagnet flux, and vice versa. The torque produced is proportional to the product of upper and lower electromagnet fluxes and the sine of the angle between them.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
