Drawn vacuum arc behaviors of 1/2 coil-type axial magnetic field contact

Abstract

The objective of this paper is to investigate the transition of drawn vacuum arc anode discharge modes of the 1/2 coil-type axial magnetic field contacts. The diameter of the contact used in the experiment include 60 mm and 63 mm. The opening velocity is 1.5 m/s from the contact separation to the 75% of full contact stroke of 15 mm. A dynamic solid angle Ω I as well as Ω II is used to evaluate the transition of anode discharge mode. Either the Ω I or the Ω I is defined as a ratio of contact diameter on contact separation, at which the transition from intense arc mode to diffuse arc mode or from the diffuse arc mode to the anode spot mode occurs, respectively. Test results show that the transition from intense arc mode into diffuse arc mode is dominated by the Ω I , rather than the axial magnetic flux density B axial . However, the transition from diffuse arc mode into anode spot mode is dominated by the B axial , rather than the Ω II . The arcing interval t I , from the initiation of vacuum arc to the evolving of the intense arc mode into diffuse arc mode, increases with the decreasing of Ω I , and with the increasing of B axial . The arcing interval t II , from the initiation of vacuum arc to the formation of the anode spot, increases with the decreasing of Ω II , and with the increasing of B axial .