Analytical and numerical computation of natural resonance frequencies of different stator arrangements taking account of the electrical insulation as well as the material the coils are built up.

The optimization process of the magnetic circuit of electrical machines leads to several well known problems, e.g. undesired additional losses due to occurring saturation effects. Moreover, the switched reluctance machine type shows the distinctive tendency to have a poor vibration and acoustic noise behavior. The vibration and resulting acoustic noise becomes severe when the stator resonance occurs, e.g. when the frequencies and waveforms of the exciting magnetic force distributions coincide with the normal mode shape and natural frequencies. Thus, a deeper knowledge about the natural frequencies of the machine construction is of crucial importance to overcome those undesired acoustic noise effects. The natural mode shapes are set by the dimensions of the complete stator geometry with coils and insulation components and in particular by the mechanical characteristics of the chosen materials. A deeper knowledge about the influences of different assembled material components, such as e.g. the windings material, to the resonance behavior is presented with analytical and numerical approaches. The advantage of the proposed analytical method is a very fast estimation of critical resonance frequencies of the switched reluctance machine. Comparatively, the performed numerical analysis needs much more time and resources, but delivers more accurate results