The brush holder of the slip ring system is without a carbon brush wear alarm device, When the carbon brush is abnormally worn, it cannot actively provide an early warning signal to the site maintenance personnel. In order to prevent the burning of the slip ring caused by overdue replacement of the carbon brush, frequent replacement is carried out annually, resulting in the replacement of many unnecessary carbon brush supports.

Each carbon brush is equipped a wear alarm device which is to ensure safety and stability. The qualified cables need excellent performance such as temperature resistance, flame retardant, wear resistance, cold resistance and tensile resistance. After the retrofit is completed, the carbon brush alarm needs to be fed back to the PLC module to generate the corresponding alarm code.