A new approach for overload cum short circuit protection of three phase induction motors using axial leakage flux

Conventional overload protective devices for induction motors like thermal, induction type, static and digital protection require motor current/s as the common parameter to be sensed accurately for reliable operation of the relay. The paper reports development of a novel overload cum short circuit protection relay for three phase induction motors without requiring motor current as its input parameter. The axial leakage flux of the motor is used instead as the sensing parameter.