Vacuum fuse having magnetic flux generating means for moving arc

摘要

A vacuum fuse includes a pair of metallic spiral elements of different wrapping directions mounted on inner end portions of axially aligned conductor rods. The radial inner ends of spiral elements are electrically connected to respective conductor rods and the radial outer ends are electrically connected to outer metallic rings, respectively. Arcing electrode disks are mounted to opposite axial ends of the outer rings to define confronting spaced apart and parallel arcing surfaces. A fusible element is connected between the conductor rods. When the fusible element is broken by an excess current, an arc is produced between the arcing surfaces and a magnetic flux is induced by the current flowing through the spiral elements. The magnetic flux causes the arc to move so that each arcing electrode is prevented from being locally heated, thereby improving the current interrupting property of the fuse.