Objective Affected by current-carrying friction operating characteristics, axle-end grounding devices of high-speed trains are prone to failure. To support effective vehicle inspection, maintenance, and fault diagnosis, it is necessary to investigate the influence of poor conductive conditions on the performance of axle-end grounding devices.

Method Based on practical operation and maintenance experiences, common faults of axle-end grounding devices are identified. Experimental investigations are conducted on six types of faulty specimens: carbon brush sticking, grease contamination, damaged terminal lug, loose installation of terminal lug, insufficient crimping of terminal sleeve, and broken cable strands. Bench tests are carried out to simulate the service process of axle-end grounding devices with fault characteristics under actual operating conditions. By measuring the operating temperature and wear amount of the specimens and observing their surface conditions, the performance variation laws of axle-end grounding devices under different fault conditions are investigated.

Result & Conclusion  Six fault types may lead to varying degrees of increase in carbon brush temperature, and higher steady-state carbon brush temperatures correspond to greater wear. As the distance between the fault location and the carbon brush increases, the influence of the faults on the grounding device temperature rise gradually decreases. Among the faults, carbon brush sticking and grease contamination may cause a sharp rise in the temperature of the grounding device, resulting in overheating after 277 and 28 minutes of energized operation, respectively. A damaged terminal lug and insufficient crimping of the terminal sleeve cause significant increase in carbon brush temperature and accelerated wear, with steady-state temperatures maintained at 92°C and 90°C, respectively, and wear amounts increase by approximately 16% and 14% compared with normal specimens. Loose installation of terminal lug increases the steady-state temperature of the faulty specimen by 4°C in comparison to a normal specimen, with a slight increase in wear amount. But broken cable strands have a relatively minor effect on carbon brush temperature.