Importance

Loading Importance Indicators...

Abstract

For interrupting all values of electric current in a high voltage circuit which cause operation of a fuse within one hour, a plurality of parallel connected helically configured fusible elements formed preferably of cadmium are embedded within quartz sand in granular form disposed within a housing structure which includes a tubular member of insulating material to the ends of which terminal caps are secured and connected to the ends of the fusible elements respectively so that currents of a high order of magnitude are interrupted in a fraction of a half cycle in a current limiting fashion and so that currents of a low order of magnitude and which are slightly in excess of normal rated load current of the fuse cause the temperature of the fusible elements to rise to approximately the melting point so that the fusible elements melt in random sequence following which arcs are established progressively by commutation action along a substantial portion of the length of each fusible element by direct arc contact, by thermal conduction from arc heat and by the flow of current therethrough so as to transform it into metal vapor and oxides thereof which are dispersed quickly into the silica grains so as to establish a gap sufficient to withstand the recovery voltage.

Loading the Abstract Image...

First Claim