Experimental Study On The Arc Discharge And Temperature Rise Of The Contact Strip During A Contact Strip Rubbing Against A Contact Wire With Electric Current

Electrified railway is favored in many countries due to its excellent characteristics such as high speed, large transportation capacity, clean energy and so on. Electrified railway has entered a high speed development period in our country. The work condition of the pantograph-catenary system as important current-collecting parts of the electric locomotive becomes very severe with the increasing of the locomotive speed.In the dissertation, a series of experimental tests have been conducted on a high speed ring-on-block friction and wear test machine. The effects of the normal contact pressure, electric current and sliding velocity on the arc discharge energy and temperature rise of the carbon strip have been studied. The main following conclusions can be drawn:Without electrical current, the temperature of the pure carbon contact strip rises with the increasing of the normal contact force. The temperature of carbon strip increases with increasing the relative sliding velocity between the contact strip and contact wire. With electric current, the energy of arc discharge between the strip and contact wire decreases with increasing normal contact pressure, and the peak temperature of pure carbon strip decreases as well. Increasing electric current will lead to the increasing of the energy of arc discharge and sharply increasing of the peak temperature of carbon strip. When the sliding velocity is increased, the energy of arc discharge between the contact strip and contact wire increases and the peak temperature rise of carbon strip increases as well.The increasing of the normal contact force not only leads to the decreasing the peak temperature, but also suppress the fluctuation of the dynamic temperature in the stable stage of the temperature of the contact strip. The greater the contact force, the more slightly the peak temperature increases. Increasing the sliding velocity leads to the increasing of the energy of the arc discharge between the contact strip and the contact wire, but it cannot affect directly the energy of arc discharge. The sliding velocity has a direct influence on the stability of the friction system, and increasing sliding velocity will lead to a poor stability of the contact strip and contact wire system.The temperature rise of a contact strip is affected by the energy of arc discharge. The larger the energy, the higher the temperature rise of a contact strip is. Therefore, there is a positive correlation between the energy and the temperature rise and the correlation is strong. The work parameters also have some influences on the temperature rise of the contact strip: the temperature rise increases with increasing electric current and sliding velocity and a large normal contact force can suppress the rise of the carbon strip temperature to some extent.The temperature rise of contact strip has a strong correlation with the wear volume. When the temperature rise of a contact strip increases, the wear volume increases linearly. The temperature rise of contact strip also has some influences on the current-carrying efficiency. When the temperature increases, the current-carrying efficiency increases slightly. When the temperature rise of the contact strip at a lower level, the wear mechanism is mainly mechanical wear (abrasive wear). The material loss is attributed to abrasion wear. Therefore, after the temperature increases, the adhesive wear becomes very obvious and there is an obvious arc erosion area. When the temperature increases up to 200℃, there are thermal stress cracks and exfoliates phenomena. When the temperature increases up to 300℃ or above, the area of exfoliates becomes bigger and there are more thermal stress cracks on the worn surface.