The working surface of the conductive slip ring is worn. Once the working surface of the conductive slip ring is worn, there will be a series of phenomena such as spots, brush marks, unevenness, corrosion, burns, cracks, etc., and the conductive slip ring will easily cause short-circuit burns, etc. result. The main reason for the wear of the working surface of the conductive slip ring is the material problem. The inferior material can not withstand the long-term rotating friction of the conductive slip ring, which easily leads to the wear of the working surface of the conductive slip ring.