Acoustic noise signal evaluation due to magnetostrictive effects in electrical equipment

The inverse magnetostriction effect (IME) is investigated for noise generation, identification and evaluation in shipboard propulsion machinery applications. The finite element (FE) implementation is performed on an example drive motor in two dimensions. The FE implementation results show an increase in the forces acting on the ferromagnetic region causing more deformation in the stationary core. This deformation causes increased vibration and hence an audible noise generation. Wavelet analysis of displacement waveforms at selected points shows the involved frequency range causing noise during the operation. The results confirm the magnetostrictive origin of noise production. The importance of such information can be realized and utilized for the reduction of noise in machinery problems especially in sensitive applications.