A method to analyze asynchronous machines with broken rotor bars

In this study the cage faults occurred by the broken rotor bars are investigated for small and medium power asynchronous motors. The Flux 2D magnetic analysis software is used for calculating the magnetic and operating parameters of an induction motor having a cage fault. Magnetic analysis is conducted for the normal rotor, the rotor with single broken bar, the rotor with two, three and four broken bars in sequence. The FEM model of motor is used for calculating the transient and steady state parameter values. For the certain types of broken cage bars, the motor torque and the motor current are studied depending on the slip. The loading tests are used to determine the actual operation characteristics of the motor. Each fault condition is analyzed by means of loading and the motor current is monitored.