Study and Simulation of a Broken Induction Motor Rotor Bar Caused Motor Vibration

The paper presents the importance of motor vibration study and simulation; different faults which can appear during induction motor running and how broken rotor bar influences the whole system vibration. The environmental and internal, electrical and mechanical noises influence the normal functioning of the motor, increase the power consumption, deform the current spectrum, more heat is generated and vibrations are growing. Broken rotor bar changes the magnetic field distribution in the air gap between rotor and stator, unbalanced force appears which cause unwanted vibration and malfunctioning. Electrical equation is written for one rotor loop and the influence of the broken rotor bar is showed. The induction motor vibration can be studied through a simple system model with two degrees of freedom. The system model changes accordingly to the broken rotor bar and this change is studied through the transfer function written for rotor.