Rotor Broken Bar Fault Diagnosis of Induction Motors During Start-up

It is very difficult to extract fault characteristic weight in steady stator current spectrum.So a broken bar detection method was proposed for induction motor during start-up process.Stator current of fault characteristic frequency had modulation effect on gas magnetic field.Therefore,the stator current,electric torque and rotor speed fluctuated periodically,and these fault characteristics were very obvious during start-up process.Broken bar detection were realized by monitoring the entire start-up process of induction motors.Experimental results show that this method is quite useful.