弓网载流效率及其对碳滑板磨损性能影响的试验研究

目的研究纯碳滑板在高速载流条件下的滑动电接触特性。方法将纯碳受电弓滑板加工成尺寸为120 mm×34.5 mm×25 mm的长方形试样。在环-块式高速载流摩擦磨损试验机上,研究法向压力、滑动速度、电流对弓网载流效率的影响,比较了不同载流效率时碳滑板的磨损形貌。试验过程中实时采集接触副两端的电压、电流以及碳滑板表面温升。每组试验的滑动距离为150 km,试验结束后,用SEM扫描电镜观察碳滑板的表面形貌。结果在电流恒定的情况下,电弧放电能量随着载流效率的增加而降低。在电流I=150A、滑动速度v=150 km/h的条件下,载流效率随着法向压力的增加而增加。在电流I=100 A、法向压力Fn=100N的条件下,载流效率随着滑动速度的增加而减小。在电压U=7 V、滑动速度v=150 km/h的条件下,载流效率随着电流的增加而减小。碳滑板的磨损形貌显示,载流效率较高时,碳滑板以机械磨损为主并伴随着轻微的电弧烧蚀现象;载流效率较低时,碳滑板电弧烧蚀现象非常严重,有明显的烧蚀坑。结论载流效率在一定程度上反映了弓网系统的接触稳定性。载流效率越低,碳滑板磨损越严重。

Experimental Study on Pantograph-Catenary Current-carrying Efficiency and Its Influence on Wear Resistance of Carbon Strip

This work aims to study sliding electric contact characteristics of a pure carbon strip under high speed current-carrying conditions. The pure carbon strip was processed into a 120 mm×34.5 mm×25 mm rectangular sample. A series of experimental tests were carried out on a high speed ring-on-block tester. The effects of normal pressure, sliding speed and current on current-carrying efficiency were investigated. Wear appearance of carbon contact strip at different current-carrying efficiency was compared. During the tests, voltage, current on both ends of the contact pair as well as temperature rise of the carbon strip were collected in real time. Sliding distance of each test was 150 km, and wear appearance of the strip was analyzed with scanning electron microscopy (SEM). Provided with constant current, arc discharge energy decreased as the current-carrying efficiency increased. At the electric current of 150 A and sliding speed of 150 km/h, the current-carrying efficiency of a pantograph-catenary system increased as the normal force increased. At the electric current of 100 A and normal force of 100 N, the current-carrying efficiency of a pantograph-catenary system decreased as the sliding speed increased. At the voltage of 7 V and sliding speed of 150 km/h, the current-carrying efficiency of a pantograph-catenary system decreased as the electric current increased. Wear appearance of the strip indicated that, the carbon strip was mainly subject to mechanical wear accompanied by slight arc ablation at high current-carrying efficiency. However, the carbon strip was subject to very serious ablation accompanied by conspicuous ablation pits at low current-carrying efficiency. The current-carrying efficiency reflects contact stability of pantograph-catenary system to a certain extent. The lower the current-carrying efficiency is, the worse the wear of carbon strip is.