Large-band reduction of magnetic vibrations of induction machineswith " breaking-of-impedance" interface

Magnetic vibration of induction machines is reduced, on a large-frequency band, with a breaking-of-impedance interface between stator core and frame. This device is designed with strong tangential stiffness and low radial stiffness. Two-dimensional finite-element (FE) dynamic response is proposed. It is based firstly on experimental determination of magnetic forces with search coils on a half polar pitch on the stator bore. Secondly, all characteristics of windings are determined versus temperature and frequency and homogenized with a linear mixing law. Thirdly, a FE modal analysis is optimized on the target function based on experimental natural frequencies, in order to identify the equivalent mechanical parameters of wound slots