Effects of material properties on switched reluctance motor vibration determination

The switched reluctance motor is well known for its higher acoustic noise, caused by stator vibrations. Techniques for noise reduction require knowledge of the modal frequencies, which depend on mechanical shapes and dimensions as well as material properties, for example, Young´s modulus, Poisson´s ratio, mass density, etc. It is found that the generally accepted value of Young´s modulus is not valid for a machine with laminations and no frame. This paper introduces a simple and nondestructive method for the measurement of Young´s modulus; it is then used in a finite element program to determine the resonant frequencies of SRM stator vibration. The effects of mass density and Poisson´s ratios are also discussed. The FE results are validated by vibration tests, which show good accuracy.