Vibration Reduction by Magnetic Slot Wedge for Rotating Armature Permanent Magnet Motors

Under the influence of the slot effect, the harmonic air-gap magnetic field is able to generate the electromagnetic excitation force, which is regarded as the important contributing factor for the stator vibration of the rotating armature permanent magnet motor (RAPMM). In order to reduce the vibration generated by the RAPMM, the method of placing magnetic slot wedge (MSW) at the slot opening is put forward accordingly. Through the employment of analytical calculation and finite element simulation, it is finally shown that the MSW is capable of weakening the harmonic of the air-gap flux density, as well as decreasing the high-frequency component of the electromagnetic excitation force. Therefore, it is acknowledged that MSW can suppress the vibration of corresponding frequency on the stator significantly. Finally, through the verification by experiments, it is obtained that the built-in MSW is deemed as an effective measure which can be employed to reduce the vibration of the RAPMM.