Vibrational behavior investigation approach and Influence of contact coefficient on stator natural frequencies

This paper presents a summary of a vibrational behavior investigation of a 27 slots / 24 poles combination surface mounted synchronous electric motor. To achieve this investigation, first, an electromagnetic analysis is done using a quasi 3D finite element model allowing to consider the rotor skewing and to compute the machine magnetic quantities. Second, a modal analysis is done using a 3D FE structural model in order to compute the motor natural frequencies, which are correlated with the magnetic pressure harmonics to extract the possibly excited modes. Third, a structural mechanical analysis under static magnetic loads is done, in which the vibrational response for each harmonic of the magnetic pressure is computed in order to determine which harmonic is responsible of high order displacements. Finally, a structural mechanical analysis under time varying magnetic loads is done to compute machine's vibrational response for a chosen operating speed using the corresponding local magnetic forces distribution.