Title :
Shaft current in AC induction machine. An online monitoring system and prediction rules
Author :
Ong, Raymond ; Dymond, J.H. ; Findlay, Raymond D. ; Szabados, Barna
Author_Institution :
GE Ind. Syst., Peterborough, Ont., Canada
Abstract :
This paper looks at a system for online shaft current monitoring. The proposed method of shaft current monitoring is noninvasive, reliable, portable, and low cost. Causes of the shaft current are described and prediction rules introduced. Fault conditions such as air-gap eccentricity, slot harmonics and broken rotor bars or end rings result in an asymmetrical flux pattern around the shaft, hence, resulting in shaft voltage. Bearing failures can occur when the voltage level exceeds the threshold of the oil film. The importance of the oil film is described
Keywords :
asynchronous machines; electric current measurement; electrical faults; harmonics; machine testing; machine theory; machine windings; magnetic flux; monitoring; AC induction machine; air-gap eccentricity; asymmetrical flux pattern; bearing failures; broken end rings; broken rotor bars; fault conditions; oil film threshold; online shaft current monitoring system; shaft current prediction rules; shaft voltage; slot harmonics; Assembly systems; Bars; Condition monitoring; Costs; Industry Applications Society; Lubrication; Petroleum; Shafts; Testing; Voltage;
Journal_Title :
Industry Applications, IEEE Transactions on
