Types of Faults and Condition Monitoring Methods of Induction Motors

Abstract

Induction motors are the electromechanical devices used to convert electrical energy into mechanical energy and work under the principle of mutual inductance. They have stator and rotor as two major parts. They run at constant speed when the supply voltage and frequency are constant and are suited for constant speed drives. They have rugged construction but working environment causes different faults. As per IEEE and EPRI study on induction motor faults, bearing fault and stator faults are 46% and 36%, respectively. The broad categories of the fault are stator winding fault, broken rotor fault, rotor mass unbalance fault, bowed rotor faults, single phasing fault, bearing fault, and crawling. Unbalanced stator voltage and current, oscillations in torque, drop in efficiency and torque, overheating and unwarranted vibration are the effects of these faults. Undetected faults cause complete failure of motor and it is costly in terms of lost production time, maintenance cost, and wasted raw materials.