Experimental Study on Evolution of Wear Mechanism of Contact Strip with Electric Current

In order to investigate the friction and wear behavior of the high-speed pantagraph-caternary system, a high speed ring-block wear tester was used to study the wear characteristics of carbon contact strip and the arc discharge phenomenon between the copper alloy contact wire and the carbon contact strip with electric current. The tests were conducted under the condition of electric current 200 A, normal load 70 N, and sliding speed 80-160 km/h. A optical microscope was used to observe the topography of the strip's wear surface. The results indicated that vibration and arc discharge occurred to the contact strip and intensified with sliding time; the arc discharge frequency increased first and then kept stable gradually. With the experimental time increasing, the average single arc discharge energy increased; the wear loss increased slowly first and then increased sharply. When the sliding speed was 160 km/h, the value of wear rate at the test time of 50 min (0.037 27 g/km) is 3 times that of 10 min (0.013 40 g/km). Under the high-speed operation conditions with electric current, the wear mechanism of the strip changed from a slight mechanical wear to a serious mechanical wear accompanied with slight arc erosion, and finally to a mechanical and arc erosion mixed wear.