Anode spot threshold current of four pure metals subjected to axial magnetic field in vacuum arcs

High current vacuum arcs are essentially metal vapor arcs, and the contact material has a directly impact on the vacuum arcs. The objective of this paper is to experimentally determine the anode spot threshold current subjected to axial magnetic fields for four pure metals in vacuum arcs. Four pure...

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Bibliographic Details
Main Authors: Zaiqin Zhang, Hui Ma, Yuting Zhang, Xiuli Yi, Zhiyuan Liu, Xiaojun Wang, Gang Li, Wenbin Wang
Format: Conference Proceeding
Language:English
Subjects:
anode spots
Anodes
axial magnetic field
contact materials
Interrupters
Iron
Magnetic fields
Threshold current
Vacuum arcs
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Summary:High current vacuum arcs are essentially metal vapor arcs, and the contact material has a directly impact on the vacuum arcs. The objective of this paper is to experimentally determine the anode spot threshold current subjected to axial magnetic fields for four pure metals in vacuum arcs. Four pure metals are W, Mo, Cr and Fe respectively, which covers a wide range of thermal and electrical parameters. The experiments were performed in a demountable vacuum chamber, and a pair of Helmholtz coil was set in the chamber to supply axial magnetic fields. Arc current in the experiments was in a range from 2kA to 30kA at 50Hz. A high-speed charge-coupled device video camera was used to record the arc evolution through an observing window. The onset of anode spot phenomenon was determined by high-speed photographs, arc voltage and contact erosion pattern. By a combination criterion, the anode spot threshold current for different materials were presented. The results show that the thermal and electrical parameters have a significant influence on the anode spot formation and the anode spot formation has an intimate connection with anode surface heat transfer process. The results also show that the axial magnetic flux density can improve the threshold current significantly.
ISSN:1093-2941
DOI:10.1109/DEIV.2016.7748719