Analysis of airgap flux, current, and vibration signals as a function of the combination of static and dynamic airgap eccentricity in 3-phase induction motors

This paper provides new information for the on-line diagnosis of airgap eccentricity in 3-phase induction motors. A new theoretical analysis of the interaction between harmonic field components due to static and dynamic rotor eccentricity which previous research has not considered is put forward. The resultant non-supply-frequency current components produced in the supply current which are highlighted by the analysis are found to exist experimentally and indeed shown to be a function of the combined effect of both dynamic and static eccentricity. Further vibration analysis is put forward to identify which particular form of rotor eccentricity is dominant; hence illustrating how faults can be identified in a motor using condition monitoring techniques.