Many induction motor broken bar diagnosis methods are based on evaluating special components in machine signals spectra. The frequencies of these components depend on slip. Evaluating fault frequencies in current spectrum is more practical. When the load or power system frequency varies or oscillates, Difficulties appear in fault diagnosis - especially when other obtrusive frequency components are present. Furthermore some fault components show irregular behavior. This thesis presents a new reasoning to show effects of regional saturation as well as slip oscillation on fault components. It is shown that these two factors are the cause of irregularities. Two new diagnosing methods are presented. One is based on simultaneous sampling of current and vibration. The other requires a vibration sensor. Velocity oscillation due to broken rotor causes frequency components in vibration spectrum. A method is presented to find the components related to rotor fault in both current and vibration spectrum. It is shown that a fault diagnosing system - based on winding function simulations of faulty motor and real measurements of healthy motor - can easily categorize the existence and the severity of fault according to the features extracted from the presented method.
