A New Method To Discriminate Eccentricities In A Three-Phase Squirrel Cage Induction Motor

This paper describes a new method, the stator instantaneous complex apparentpower envelope (SICAPE), for the dynamic simulation of static, dynamic, and mixedrotor eccentricities and for discriminating among them in open- and closed-loop squirrelcage induction motors. The magnetically coupled circuit model is based on a windingfunction approach (WFA) to calculate the inductances and their mutuals, allowing allharmonics of magnetomotive force (MMF) present in the stator current spectra to beconsidered. The FFT method was applied to the stator current at no-load and loadconditions, and results were compared to discriminate the characteristic frequencycomponents areas to define eccentricity type. Simulation results show the theoreticalaccuracy of the technique and the detailed differential equations describing the machineperformance effectiveness, and all three mentioned rotor eccentricities that have beendiscriminated from each other are presented.