Reducing sound and vibration levels of a brushless dc motor

In order to take significant role in household appliance competition new technologies are launched continuosly recent years, which brings sound and vibration problems. Sound and vibration is one of the most important quailty criteria of the household appliance, therefore sound and vibration level has become main issue in the competition. At this aspect so many articles written by several firms exist in literature.Interaction of different components of household appliance creates dynamic forces which act on each other cause trouble more chaotic. Considering the electric motor as the heart of the household appliance system, initial defects arise in this region in the meaning of sound and vibration. Although increasing isolation between motor and machine is a good solution, motor itself must be investigated in detail to eliminate the problem in the source. In this manner the dynamic forces in the motor act on each component will be decreased to minimum level.In this thesis a permanent magnet motor driven with electronic is studied. Although there are projects related to sound and vibration level reduction by software, the focus of this thesis is to find out minimum sound and vibration levels of motor via working on its modal behaviours.