# A Study on the Pantograph Slide Wear Model Based on Energy Dissipation
## 6 Discussion  
Relationship Between Pantograph-Catenary Current-Carrying Frictional Energy Dissipation and Contact Current, Contact Pressure, and Sliding Speed  
Under a sliding speed of 80 km/h and a contact pressure of 90 N, the characteristic curve of pantograph slide wear with respect to the frictional force under varying current conditions was obtained, as shown in Figure 5.  
As shown in Figure 5, when the contact current is set to 100 A, 150 A, 200 A, and 250 A, the pantograph-catenary frictional force decreases, while the wear of the pantograph slide increases as the frictional force decreases. Under a constant sliding speed and contact pressure, the wear of the pantograph slide exhibits a negative correlation with the frictional force as the contact current increases. This is because, with an increasing contact current, the energy generated by the current increases, resulting in a rise in the surface temperature of the pantograph slide. This temperature rise causes the softening of the \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameter** & **+10\% Variation Rate** & **\(-\)10\% Variation Rate** & **Average Sensitivity** \\ \hline Contact Pressure (\(F\)) & +8.2\% & \(-\)7.5\% & 0.79 \\ Electricity (\(I\)) & +10.1\% & \(-\)9.3\% & 0.97 \\ Sliding Speed (\(v\)) & +9.7\% & \(-\)8.9\% & 0.93 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Sensitivity coefficients of key parameters. contact surface material, reduces the mechanical interlocking between micro-asperities, and lowers the shear resistance at the contact points. Consequently, the surface material and wear debris are more easily sheared and extruded, leading to increased pantograph slide wear. Additionally, the elevated temperature promotes oxidation reactions on the sliding electrical contact surface, forming an oxide film that provides a certain degree of lubrication. This reduces the friction coefficient and, in turn, the frictional force, which explains the observed decrease in the frictional force with increasing currents [28]. The variations in pantograph-catenary current-carrying frictional energy dissipation under different contact currents at a sliding speed of 80 km/h and a contact pressure of 90 N are shown in Figure 6.  
As shown in Figure 6, with the increase in the contact current, there is a significant change in the energy contributions from the work done by friction and by the current. The energy generated by frictional work decreases, while the energy generated by electrical work increases gradually. At a contact current of 150 A, the energies contributed by both mechanisms are approximately equal. As the contact current continues to increase, the total  
Figure 5: Characteristic curve of wear volume with friction under variable current. Figure 6: The variation law of the pantograph–catenary current-carrying friction dissipation energy under different contact currents. dissipated energy increases accordingly. Combined with the analysis of Figure 5, it can be observed that, when the contact current is between 0 and 150 A, the pantograph-catenary frictional force remains relatively high, and the energy from frictional work exceeds that from electrical work, indicating that mechanical wear is dominant. When the contact current reaches 150 A, the energies from both sources are nearly balanced, suggesting a relative equilibrium between mechanical and electrical wear. At 200 A, electrical work produces more energy than frictional work, and, at 250 A, the energy from electrical work is approximately 3.35 times that from frictional work, indicating that electrical wear becomes the predominant wear mechanism for the pantograph slide.