| 摘要 |
<p>FUSING ELEMENT FOR A CIRCUIT PROTECTOR The fusible element of an electric fuse has a first electrical conducting path, a second electrical conducting path in electrical parallel relation with the first electrical conducting path, a weak spot in the first electrical conducting path which can respond to a potentially-hurtful overcurrent to fuse and thereby form a first arc in the first electrical conducting path, and a weak spot in the second electrical conducting path which is longitudinally displaced from the weak spot in the first electrical conducting path and which can respond to that overcurrent to fuse and thereby form a first arc in the second electrical conducting path. The weak spots in the electrical conducting paths form primary arcs in those electrical conducting paths as they fuse; and one important function of those primary arcs is to establish the point at which the rate of rise of the overcurrent starts to diminish, while another important function of those primary arcs is to burn the adjacent portions of the respective electrical conducting paths. When enough of the cross sections of those adjacent portions have burned to enable those adjacent portions to fuse, secondary arcs will develop at those adjacent portions; and an important function of those secondary arcs is to provide the desirable current-interrupting characteristics that the seriesarranged weak spots of a fusible element can provide when they fuse simultaneously. The cross sections of the weak spots are made relatively small; and hence the primary arcs which form as those weak spots fuse enable the electric fuse to establish a relatively low point at which the rate of rise of the overcurrent starts to diminish. The current-interrupting characteristics of the secondary arcs, which form as the adjacent portions of the respective electrical conducting paths fuse, will co-act with the relatively low point, at which the rate of rise of the overcurrent starts to diminish, to quickly reduce the current to zero.</p> |
