Vacuum arc behavior and its voltage characteristics in drawing process controlled by composite magnetic fields along axial and transverse directions

Abstract

In this research, drawing vacuum arc (VA) experiments were conducted using composite contacts under currents ranging from 5 kA to 20 kA root mean square (rms). The new type of contact comprised an axial magnetic field (AMF) configuration and a transverse magnetic field (TMF) configuration. The TMF plate was in the center, surrounded by the AMF plate. The contact generated both AMFs and TMFs simultaneously. VA appearances and arc voltages were recorded, and the VA was modeled as a conductor for electromagnetic force analysis in ANSYS software. The results showed that the coaxiality of operating mechanisms significantly influenced arc behavior just as the arc was ignited. When arc brightness did not increase after ignition, there was a voltage drop accompanied with diffusion of the VA. As to VA development, when an arc was ignited on an AMF plate, it spread on the plate and rotated. Over time the arc current increased, the constricting arc forms, and the arc column rotated on the TMF plate under the action of Ampere's force. With regard to the influence of a magnetic field on a VA at different stages, in the initial drawing arc stage the TMF was dominant, and the arc started to rotate under the action of Ampere's force. Afterwards, the AMF was dominant, with a steadily burning arc. As for contact melting, in the initial arcing period, a contracted short arc caused severe melting and erosion of the contact plate. When the ignition spot or root was close to the slot of plate, the electromagnetic force pushed the arc toward slot and contact edge, resulting in local erosion of the slot region.

Influence of petal parameters on the electromagnetic force driving the arc in RMF type vacuum interrupters

“…Conventionally, the arc motion is studied using high-speed optical photography. The arc motion and behaviour have been observed and analysed for different variants of the RMF contact such as contrate cup type contacts [7,8], spiral petal contacts [9,10], SWASTIK shaped contacts [11] and also hybrid RMF-axial magnetic flux contact designs [12]. Finite-element method (FEM) is extensively used in analysis and design of VIs [13,14] including the computation of the Lorentz force on the arc [5,6,11].…”

Exploring the low redshift universe: two parametric models for effective pressure

“…On the other hand we may ask why there is dominance of the cosmological constant over the matter component at the present epoch. These two basic problems prompt us to propose some alternatives, which include an evolving scalar field called quintessence [2][3][4][5][6][7][8], a noncanonical scalar field (such as K-essence [9][10][11], phantom [7,8,[12][13][14][15][16][17][18]), modified gravity [7,8,[19][20][21][22][23], coupled dark energy [8,24,25] or decaying dark energy [26] models, and so on. On the other hand, the equation of state (EoS) parameter of the cosmological constant is precisely ω de = −1.…”