Process Of Arc Moving Affected By External Magnetic Field In Magnetic Driven Arc

Abstract

Magnetic driven arc has been applied to DC breaker and fault current limiters. However, it has not been researched, especially stagnation and re-strike of the arc. In this paper, the process of arc moving affected by external magnetic field in magnetic driven arc is elucidated. Specifically, the behavior of magnetic driven arc with external magnetic field is measured by using the oscilloscope and HSVC (High Speed Video Camera). And an external magnetic field (1, 2, 3 mT) was applied by helmholtz coil. As a result, the arc mean moving speed increases with increasing the external magnetic field. The arc of re-strike time increases and stalemate time decreases with increasing the external magnetic field. Therefore, the anode spot moving speed increases 8 times because arc of re-strike occurs easily with the external magnetic field. Thus, the erosion of electrodes decreases and the arc moving becomes the smooth. However, the distance of re-strike decreases with increasing the external magnetic field because re-strike point is affected by cathode jet. The anode restrikes on the extension of the cathode jet. Therefore, the direction of cathode jet contributes to the process of arc moving.