Finite element analysis and on-line current monitoring to diagnose air gap eccentricity in 3-phase induction motors

This paper applies finite element analysis to predict the frequency components in the current signal which are a function of air gap eccentricity in a 3-phase squirrel-cage induction motor. The magnitude of the components and hence the severity of the fault are predicted and compared with experimental results for static and combinations of static and dynamic eccentricity. Closer agreement is consistently found between calculated and measured magnitudes in comparison to previous attempts using the MMF and permeance wave approach.