✔ Operating Principle Of Induction Disc Relay

Operating Principle Of Induction Disc Relay

- April 07, 2018

In construction also it is identical to induction motor. Construction and working principle of instantaneous over current relay is quite simple.

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Induction cup relay is also a type of induction disc relaysthe basic principle on which induction cup relay works is same as that of induction motor.

Operating principle of induction disc relay. They are not used with dc quantities owing to the principle of operation. Electromagnetic induction relays use the principle of the induction motor where torque is developed by induction in a rotor. Elect romagnetic attraction relays operate by virtue of a plunger being drawn into a solenoid or an a rmature being attracted to the poles of an electromagnet.

The induction type relays are also called magnitude relaysthese relays work on the principle of the induction motor or an energy meterin these relays a metallic disc is allowed to rotate between the two electromagnetsthe coils of the electromagnets are energised with the help of alternating currents. Induction type relays are the most widely used for protective relaying. The figure shows a four pole induction cup relay.

The basis construction of this relay is just like four poles or eight pole induction motor. Operating principles there are really only two fundamentally different operating principles. The operating torque is produced by electro magnetic attraction or by electromagnetic induction.

These electromagnetic relays use the induction principle discovered by galileo ferraris in the late 19th century. Electromagnetic induction relays operate on the principle of induction motor and are widely used for protective relaying purposes involving ac quantities. Here generally a magnetic core is wound by a current coil.

This operating principle applies only to relays actuated by alternating current and called induction type relays. 1 electro magnetic attraction and 2 elect romagnetic induction. Non directional induction overcurrent relay construction.

The restraining torque is given by the springs. This relay is also called earth leakage induction type relaythe overcurrent relay operates when the current in the circuit exceeds a certain preset valuethe induction type nondirectional overcurrent relay has a construction similar to a watthour meter. The magnetic system in induction disc overcurrent relays is designed to detect overcurrents in a power system and operate with a pre determined time delay when certain overcurrent limits have been reached.

Induction cup relay work in same principle of induction disc relay. The relay operates when the operating force is greater than the restraining force. A piece of iron is so fitted by hinge support and restraining spring in the relay that when there is not sufficient current in the coil the no contacts remain open.

The number of poles in the protective relay depends upon the number of winding to be accommodated.