The unbalanced magnetic pull and its effects on vibration in a three-phase generator with eccentric rotor

The unbalanced magnetic pull (UMP) in a three-phase generator under no-load, caused by dynamic and static eccentricity, is calculated theoretically. The air-gap permeance is expressed as a Fourier series. Analytical expressions of the UMP for any pole-pair number are obtained. Effects of relative eccentricity and pole number on the magnitude of the UMP are obtained. The vibration of a model rotor in a three-phase generator under the action of the UMP and the eccentric force is analyzed by the numerical method and the harmonic analysis. (C) 2002 Elsevier Science Ltd. All rights reserved.