Analytical Prediction of Instantaneous Torque and Speed for Induction Motors with Mixed-Eccentricity Fault Using Magnetic-Field Equations

Abstract

This article describes an analytical approach to predict the instantaneous torque and speed curves of a three-phase induction motor under a mixed-eccentricity fault. This approach can be utilized to predict the type and degree of eccentricity using the modified three-phase stator magneto-motive forces for a mixed-eccentricity fault in which slotting and saturation effects are taken into account. The computation is based on the analytical solution of field equations in cylindrical coordinates using Laplace and Poisson equations with the current density as an input. Frequencies of the predicted instantaneous torque with and without a constant load associated with the mixed-eccentricity fault are discussed and compared with healthy motor performance. Some experimental results are presented to verify the predicted results.