Bearing damage analysis in a large oil-ring-lubricated induction machine

In this paper, an alternative method of online detection capable of discerning machine failure modes resulting in shaft current is proposed. The relationship between shaft current and fault conditions such as asymmetrical flux due to joints in the lamination segments, broken rotor bars, air-gap eccentricity, saturation, and slot harmonics are investigated. The diagnostic equipment used in the investigation of a three-phase medium-voltage squirrel-cage induction machine is described. The experimental results using the alternative method of online detection of shaft current are presented