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 and dynamic eccentricities 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. More important, it is shown for the first time that a link exists between the low- and high-frequency elements of these harmonics. It is also shown that these high-frequency components are not very strong in all types of machines. These results will be, useful in generating rules and laws to formulate online, 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.