Rotation Characteristics of Vacuum Arcs Driven by Transverse Magnetic Fields

The objective of this paper is to propose a new method to quantitatively determine the arcing rotation characteristics of the constricted vacuum arc driven by the transverse magnetic field (TMF). This method is based on a split-anode TMF contacts' system, including a split-anode TMF and a spiral TMF cathode. Experiments were carried out in a demountable vacuum chamber. Both contacts had a diameter of 60 mm. The anode surface was divided into four areas: one central area and three symmetrically peripheral annular areas. The currents of the four split-anode areas were measured using four Rogowski coils situated outside the vacuum chamber. The observed arc behavior was recorded by a high-speed charge-coupled device video camera. This experiment proposes a new method to quantitatively determine the arcing rotation velocity of the TMF vacuum arcs by the current waveforms of the four split-anode areas. After some comparison to the new method, the rotation velocity of the TMF vacuum arcs estimated in the traditional method by the arc photographs seems underestimated. The experimental results indicate that the constricted vacuum arc driven by the TMF should be higher than 471 m/s with the arc current of 16-kA rms. The results also reveal the corresponding anode current distribution characteristics under the TMF in different arc stages during the arcing period.