Affiliations: School of Electrical Engineering and Automation, Hefei University of Technology, Hefei, Anhui, China
Correspondence:
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Corresponding author: Xiaohua Bao, School of Electrical Engineering and Automation, Hefei University of Technology, Hefei 230009, Anhui, China. Tel.: +86 055162905883; Fax: +86 0551 62904435; E-mail: sukz@ustc.edu
Abstract: Eccentricity is a common fault during the operation of
electrical machines due to manufacturing error and effect of rotor
deflection. Therefore, eccentricity fault has been a research hotspot in
recent decades for the reliable running of machines. The monitoring signals
for detecting eccentricity have been proposed in many published papers.
However, the effects of rotor slot number on the magnitudes of
characteristic signals are seldom investigated. Thus, this paper presents
the relationship between the number of rotor slots and the monitoring
signals under static, dynamic and mixed eccentricity on the basis of the
previous papers. The theoretical analysis shows that not all electrical
machines generate the principal slot harmonics in the stator current. But
these harmonics in the air-gap magnetic field are easily detected for all
machines when the machines are under static or dynamic eccentricity.
Moreover, the effect of rotor slot number on the low-frequency components
under mixed eccentricity is also predicted. Detailed simulations are
presented for a high voltage submersible motor with 40, 41, 42, 43 and 44
rotor slots under various conditions. And these results well verify the
theoretical predictions.
Keywords: Eccentricity, monitoring signals, rotor slot number, submersible motor
