A Novel Structure Fan to Reduce Noise and Mechanical Loss of Motors

In this paper, a novel structure fan passively switching between synchronous and asynchronous rotation is proposed as a novel fan system to reduce noise and mechanical loss at high speed, and the design method and measurement results of the fan speed are described. We select materials for each part to reduce leakage magnetic flux, and increase the torque (eddy current torque) of a torque limiter of the fan by increasing the number of magnetic poles in the torque limiter. Measurement and analysis results show that the eddy current torque of the torque limiter could be designed with high accuracy. The relationship between the eddy current torque of the torque limiter and the fan rotation speed is generally consistent between measurements and analysis. The measurement shows that the novel structure fan can reduce the fan speed by 11% at high shaft speed of 5000 min^-1, and the result can lead to lower the mechanical loss by 19% than a conventional fan. In addition, the measurement results revealed that the novel structure fan has the potential to reduce the fan loss by 51% by reducing bearing friction.