Stator current harmonics in saturated cage and wound rotor induction motors

The analytical expressions for stator current harmonics frequencies in the spectrum of saturated cage and wound rotor induction motor are derived in the paper. Knowledge of stator current spectrum of healthy motor supplied by symmetrical three-phase voltages is the starting point for application of the most popular noninvasive diagnostic and condition monitoring technique of these machines - motor current signature analysis. Presented analysis is based on the MMF-permeance wave approach. Analytical results obtained were confirmed by experimentally obtained stator current spectrum. Experimentally obtained stator current spectrum fully confirms the existence of current components at the frequencies predicted by derived analytical expressions.