Effect Of The Strip Inclination Angle On Friction And Wear Behavior Of Carbon Strip/Contact Wire In A Pantograph/Catenary System

With the rapid growth of Chinese high speed railway, the capacity of the railway transportation has been increased dramatically, and technical equipment has been enhanced sharply, which make a big contribution to the development of the national economy. In the high speed electrical railway system, the pantograph/catenary system is a key component by which the train gets power from the ground. The performance and the service life of the pantograph/catenary system will influence the regular running of the high speed locomotives. In the pantograph/catenary system, arc discharge is a most important cause due to abnormal wear of the pantograph strips and contact wires. It is significant to study the friction and wear properties of the pantograph/catenary system and to find out a way for suppressing arc discharge so as to extend the service life of the pantograph/catenary system.The experimental tests were carried on a high speed ring-on-block tester. The influences of different inclination angles of carbon strips and normal forces on the performance of pure carbon strip/copper contact wire were studied under the conditions of sliding velocityν=160km/h and electrical current I=100A. The experimental results lead to the following conclusions:(1) When the normal force is constant, the wear volume of the carbon strip decreases with the increasing of inclination angle. And the friction coefficient, temperature and offline arc energy of the friction pair also decrease with the increasing of inclination angle. When the inclination angle of the carbon strip is kept constant, the wear volume of the carbon strip decreases as the normal force increases. And the friction coefficient, temperature and offline arc energy of the friction pair also decrease as the normal force increases simultaneously. (2) The offline arc discharge energy released in every turn of the test disk is found to be proportional to the wear rate of the carbon strip. The pure carbon wear rate increases as the discharge energy release in every turn of the test disk increases. The offline arc discharge has resulted in severe damages of the friction surfaces of carbon strips, which include the ablation pits, pocks and streamline of erosion.(3) When the carbon strip is inclined, the carbon strip probably loses contact with the contact wire in the process of the sliding friction. And the bigger the inclination angle, the longer the separating time is. This phenomenon will have a bad effect on the current collection quality and running quality of trains. Thus, the inclination angle of the carbon strip should be controlled. According to the test results, the inclination angle of the carbon strip should be less than 2°.(4) the worn surfaces of the pure carbon strips were observed using Optical Microscope (OM) and Scanning Electron Microscope (SEM). Energy spectrum analyses were also carried on using Alpha Ray Spectrometer (EDX) simultaneously. The oxygen and copper were found in the area of arc erosion. Those phenomena show that in the process of carbon strip rubbing against copper contact wire with arc discharge, oxidation and transfer of materials take place. The bigger arc discharge energy, the severer arc erosion of the carbon strips surface is.