THE EFFECT OF WINDINGS, FRAME AND IMPREGNATION UPON THE RESONANT FREQUENCIES AND VIBRATIONAL BEHAVIOR OF AN ELECTRICAL MACHINE STATOR

In order to design a quiet electrical machine, an accurate determination of the resonant frequencies and vibrational characteristics of the stator is essential. This paper presents both a fundamental theoretical and experimental study which is designed to explore the manner in which the values of the resonant frequencies and vibrational behavior of a stator are affected by the presence of the windings, frame, and impregnation. Following a brief description of the method of analysis for the free vibrations of stators of encased construction, which is an energy method based on the theory of elasticity, details of the various models are given. It is found that the effects of both the windings and the frame are in general predictable and beneficial in so far as they tend to suppress the magnitude of the resonant amplitudes. Impregnation, however, has the opposite effect on these amplitudes but is found to play a desirable role in so far as it helps to eliminate unwanted parasitic resonances from the frequency spectrum. © 1990 Society for Experimental Mechanics, Inc.