Question

the torque produced in induction type relay (shaded pole structure) is proportional to square of "mmf"

Answer 1

$<b><i><u>Electromagnetic relays are those relays which are operated by electromagnetic action. Modern electrical protection relays are mainly micro processor based, but still electromagnetic relay holds its place. It will take much longer time to replace all electromagnetic relays by micro processor based static relays. So before going through detail of protection relay system we should review the various types of electromagnetic relays. Electromagnetic Relay Working Practically all the relaying device is based on either one or more of the following types of electromagnetic relays. Magnitude measurement,Comparison,Ratio measurement.$

Answer 2

Shaded pole structure induction types relay in torque produced is directly proportional square of current Torque = i^2×sin$