Elimination of the influence of supply mains low-quality parameters on the results of induction motor diagnostics

A method of induction motor voltages recalculation aiming at exclusion of components caused by supply mains dissymmetry and unsinusoidality from induction motor instantaneous three-phase power signal has been offered. The recalculation is made on the basis of the motor known electromagnetic parameters, taking into account the electromotive force induced in stator winding by rotor currents. The results of instantaneous power parameters computation proved efficiency of this method in case of supply mains voltage dissymmetry up to 20%. This method makes it possible to improve the accuracy of induction motor diagnostics based on the spectrum of currents and powers instantaneous values and can be developed to be used in vibrocharacteristeics analysis.