Performance analysis of a three phase induction motor under mixed eccentricity condition

A substantial portion of induction motor faults is eccentricity related. In practice, static as well as dynamic eccentricity happen to exist together. With this point in mind, an analytical approach to evaluate performance of a three phase induction motor under mixed eccentric condition has been presented in this paper. Clear and step-by-step theoretical analysis, explaining completely the presence of certain harmonics in the line current spectrum in presence of eccentricity, is discussed. The effects of the number of rotor slots, machine pole numbers which influence the current spectrum considerably; can also be fully identified. These results will be useful in generating rules and laws to formulate on-line neural network based tools for machine condition monitoring. Finite element results to substantiate the inductance values used in the simulation are also included. The analysis is validated by the line current spectrum of the eccentric machine obtained through simulation using modified winding function approach (MWFA) and experimentation.