Review on Test Benches Studying Sliding Electrical Contact and Synthesis of Experimental Results

Sliding electrical contacts are commonly used with a slip ring to collect the current in moving system generators, alternators, or electrical motors. These contacts are also found in electrical transports without batteries, which are mostly supplied by means of a pantograph-catenary system. These systems are fraught with numerous issues. Among them, it is worth highlighting wear and heating, which lead to failures and pre-worn materials. Moreover, with the increase in speed and improvements in technologies and materials, new problems emerge. This is the case with the substitution of the classic copper strip with graphite or copper-impregnated graphite. Multiple works that studied sliding electrical contacts have been achieved recently, some by trying to create a model of the system based on experimental results, and others only based on experimental works and measurements. This paper aims to review articles from this last category by making a synthesis of different test benches used and then by opening a discussion based on different results highlighted by scholars. This discussion is divided into five points that constitute the system inputs. These are the environment, material, normal load, sliding speed, and current. Based on this discussion, a conclusion attempts to evaluate topics where results and trends are commonly established by authors and topics where there is a lack of work or some conflicts in the results or trends between different articles. For this last point, some perspectives are given for further experimental works.