The fault diagnosis of rotor bars in squirrel cage induction motors by time-stepping finite element method

This paper presents a fault diagnosis of the rotor bars in squirrel cage induction motors. The defective rotor bars such as broken bars and high resistance are detected by analyzing the induced current in the coil caused by reluctance variation when the rotor is moving. In the analysis, the time stepping finite element method is used where the electromagnetic and circuit equations are coupled and the rotor movement is considered by automatic subdivision of air gap meshes. By the proposed method, various rotor fault conditions are simulated. The experimental results show that the analysis method is useful to detect rotor fault conditions.