For how will decrease the noise of the dc motor controller, there are a lot of people still don't understand.
Small make up take you to understand the next.
In to correctly choose fan material and structure, such as one-way rotating micro gear motor controller, requires a streamlined backward type centrifugal fan, centrifugal fan, brought down to the ring is lower than without a backward ring.
Increase the outer edge of the fan and fan cover clearance, cancel the air duct of obstacles, and ensure smooth wind direction, to improve the noise.
The short distance to stator winding choose reasonable.
The uneven air gap, and the use of sloping double chute structure.
The above is several methods of reducing noise dc motor controller.