2、The connection between the carbon brush and the lead wire, the lead wire and the terminal is loose, and the contact resistance is large, resulting in uneven load distribution. Check the contact between the brush and the copper braid and whether the screws in the lead circuit are tightened and the contact is in good condition.
3、 If the brand of carbon brush is not in conformity with the regulations, or some brushes of different brands are replaced, due to the inspection of the brand of brushes, the brushes are replaced with the ones designated by the manufacturer or tested as appropriate.
4、If the pressure of the carbon brush is uneven or does not meet the requirements, check the brush pressure with a spring scale and adjust it (the pressure of the brush should be 0.2~0.3MPa in general according to the regulations of the manufacturer). Pay special attention to make the pressure of each brush uniform.
5、carbon brush grinding short, carbon brush grinding short to the specified value, must be replaced.
6、The surface of slip ring and carbon brush is not clean. With the degree of cleanliness, sparks may occur on individual carbon brushes or all carbon brushes. Wipe the slip ring with white cloth dipped in a little alcohol, wipe the surface of carbon brush with clean white cloth, and grind the slip ring with fine glass sandpaper on the grinding tool.