ELECTRIC FUSES EMPLOYING COMPOSITE METAL FUSE ELEMENTS

摘要

The invention involves new high voltage current limiting fuses employing composite metal fuse elements. The composite element consists of at least two portions of different metals with different electrothermal properties extending through the melt and arc zone, the two portions being bonded to one another along their adjoining faces for good thermal exchange. One metal of the composite is aluminium which is of high conductivity and high melting point while the other is cadmium which is of low melting point, so that melting of the low melting point metal occurs at any and all locations along, the element when its temperature reaches the said low melting point. The resulting composite exhibits properties that are not the mean of the metals employed and has a reversible resistance characteristic thus facilitating the design of the fuse for low current fault interruption. An element having low melting temperature along its entire length results and gives essential arcing substantially simultaneously of the total element to improve the low current clearing performance of the fuse.