Reclosing transients in induction machines including the effects of saturation of the magnetizing branch and a practical case study

Induction motors make up the majority of the load in many industries. The industry is becoming increasingly aware of the need to ride through short term faults on the power system to improve the system reliability, particularly where motors drive critical loads. This often requires reclosing on the motor before it has reached zero speed. Such reclosures can damage the motor due to excessive current and torque transients. This paper examines the reclosing transients in an induction motor, including the effects of saturation. A practical case study is also presented with speed and back EMF measurements from a 20 HP induction motor driving a mixer in an oil refinery