Arc Dynamics and Material Erosion of Pantograph–Catenary Contacts Under a Rotating Permanent-Magnet Field

To mitigate localized erosion of pantograph–catenary system (PCS) contacts caused by random migration of arcs during contact loss, a periodic transverse magnetic field generated by a rotating permanent magnet was proposed to regulate arc motion. A synchronized high-speed imaging and electrical-signal acquisition platform was established to compare arc dynamics, current-collection characteristics, and carbon-electrode erosion under no field, a static field, and periodic fields of 5, 10, and 30 Hz at 120 V DC and 25 A, while SEM/EDS characterized surface morphology and elemental composition. The static field shortened the arcing duration and continuously stretched the arc column toward one side, but produced directional surface grooves. Under periodic fields, the arc column alternately deflected and contracted. Among rotating-field cases, 10 Hz yielded a normalized RMS current ratio of 72.923% and the lowest current fluctuation coefficient of 13.509%, whereas 30 Hz showed no further improvement in electrical or erosion performance. These results indicate that erosion mitigation is associated with both arcing energy and arc-root attachment-site renewal, and that the half-cycle at 10 Hz provides a favorable balance among arc migration, current-collection stability, and thermal-load dispersion, providing experimental guidance for selecting magnetic-drive parameters for PCS arcs.