What are the causes of carbon brush wear in brushed DC motors?

The carbon brushes of brushed motors are sometimes worn out and need to be replaced in time.

1. Smoothness of the surface of the slip ring. The higher the smoothness of the surface of the slip ring, the lower its coefficient of friction and the lower the wear rate of carbon brushes. A layer of oxidized film on the surface of the slip ring is also very helpful in reducing the coefficient of friction and the wear of carbon brushes.

2. The influence of compression spring pressure. If the compression spring pressure is too large, it will increase the mechanical wear of the carbon brushes; at the same time, if the compression spring pressure is too small, although the friction between the carbon brushes and the slip ring is very small, due to poor contact, it is easy to produce sparks, which is also undesirable.

3. The influence of current. For graphite carbon brushes, the current flowing through the positive carbon brush is greater than the current flowing through the negative carbon brush, so the wear of the positive carbon brush is greater than that of the negative carbon brush. Moreover, the wear of the positive slip ring is greater than that of the negative slip ring, so the positive and negative cable heads of the carbon brushes need to be adjusted every time they are inspected. Effect of carbon brush material.

With the above information, we can determine the quality and performance of the carbon brushes by looking at the wear rate of the brushes. The wear rate of carbon brushes is also an important factor in determining the life of the brush. The lower the wear rate, the longer the life of the brush.