The simplest structure in the motor family is the brushed DC motor. As long as the two ends of the brush are powered on, it can be operated.
Noise caused by friction between carbon brushes and commutators: friction noise is generated due to the pressure of the brushes on the rotating commutator. Generally, most motors use semi-plastic commutators. The roundness of the surface of the commutator is not good, and the mica between the sheets is slightly concave due to the engraving, which increases the friction noise and increases the frequency of the noise. The roundness of the commutator is not good and the surface of the commutator is uneven, which increases the noise.
Then, the obvious disadvantage of brushed motors is noise. So, if you want a "silent motor", you can't choose a brushed motor.
After the motor has been used for a long time, the brushes must be worn to a certain extent. After the wear, the distance between the brushes and the rotor becomes larger, resulting in poor contact and discharge under the action of voltage, that is, sparks. The more serious the wear, the sparking phenomenon occurs. More often, making good brush-to-rotor contact can eliminate sparking.
Compared with these shortcomings of brushed motors, Brushless DC Motors have none!
Advantages and disadvantages of brushless permanent magnet DC motors:
The brushless DC permanent magnet motor, from its name, the biggest advantage is "brushless". It can effectively avoid the shortcomings of brushed motors. Therefore, its main advantages are:
1. High efficiency;
2, low noise;
3, easy to cool;
4, the volume is small;
5. High stability;