Exploiting rotor slotting harmonics to determine and separate static and dynamic air-gap eccentricity in induction machines

Abstract

The paper investigates the influence of pole-pair number on the mixed eccentricity related fault indicators extracted by means of high-frequency or transient signal injection. The method exploits the transient current response to track eccentricity- and slotting-related machine saliencies. By using the fault indicator's locus, a separation of mixed eccentricity components is performed, without comparison to additional reference measurements of the faultless case (no eccentricity). It is shown, that the fault indicator related to certain machine designs can be used to extract a reliable reference from the eccentric machine. This allows for the separation of static and dynamic proportions from the overall mixed eccentricity.