How to Reasonably Design Motor Structure to Suppress Noise
Technology King's 18 years of frontline production experience teaches you how to effectively suppress motor noise
1. Adopt sine winding.
2. Choose the appropriate number of slots for the stator and rotor. A large number of stator slots result in good electrical performance but high cost, while a small number of stator slots leads to poor performance. Generally speaking, the number of slots per pole and phase in a three-phase asynchronous motor should not be less than 2, and the number of slots in the rotor and stator should be similar.
3. The stator winding adopts a reasonable short torque.
4. The asynchronous motor rotor adopts a relatively inclined double skewed groove structure to reduce axial force; DC motors use non-uniform air gaps; The AC motor adopts magnetic slot wedges.
When the motor in use generates a "sweeping chamber", the air gap can be appropriately increased to reduce the air gap flux density. When the motor power has a margin, a part of the rotor circumference can be removed.
6. Properly control the ripples, dents, roughness, and radial clearance of the bearing rolling surface.
7. Improve the surface machining accuracy and roughness of the commutator to reduce brush noise.
8. Increase the stiffness of the machine base.
9. In the design of the fan, uneven distribution and unequal length of fan blades can be used, as well as dispersed noise to reduce the outer diameter of the fan (to meet the required air volume); The fan of a single-phase motor should not be designed as a radial blade centrifugal type; The fan of a reversible motor should adopt a blade backward tilting centrifugal type; Do not install flow blocking components on the wind path.
In addition, Mr. Wang from the company has made the following judgment on the cause of abnormal noise during the operation of the electric motor
When the stator and rotor rub against each other, a piercing "crack" sound will occur, which is caused by bearing failure.
The motor is running in phase loss, and the roar is particularly loud.
When the bearing is severely lacking in oil, a "rustling" sound can be heard from the bearing chamber.
The fan blade collides with the shell or has debris, making a sound of impact.
When the cage rotor conductor bar breaks or the winding joint of the wound rotor is disconnected, sometimes there is a high and low "buzzing" sound, the speed slows down, and the current increases.
The wiring at the beginning and end of the stator winding is incorrect, with a low growl sound and a decrease in speed.
The stator slot wedge is loose or broken, and a "sizzling" sound can be heard.
