Diagnosis of the Induction Machine based on Finite Element Method

This Book presents a method for the diagnosis of induction machines faults. The proposed method is capable to detect the presence of both dynamic eccentricity and broken rotor bar faults. Several studies have attempted to model an induction machine with isolated faults and provide methods for detecting them. However the challenge begins with the occurrence of combined defects which produce fault signatures that are difficult to separate. The novel proposed method is based on the measured air-gap magnetic flux density spectrum which allows for the detection of combined faults. A finite element method is used for modelling the induction machine under faulty conditions where the faults of rotor bars are created by a deleting operation of the boundary condition which is added to the air-gap part. Then the dynamic eccentricity is formed by the movements of the rotating rotor’s centre with different ratings. From a modelling perspective the contribution of the current work is the establishment of the relation of the air-gap of the rotor for modelling this kind of eccentricity fault.