Stability of fuses under cyclic load

Thermal stresses in fuses, stimulated by the high degree of mechanical stiffness and the cause of low stability under cyclic current loads, can be reduced by reducing the stiffness of the fuse element, which is typically a strap welded to contact caps at both ends. It is indicated that the stiffness can be reduced by increasing the length and decreasing the cross section. A thin strap consists of flat and bend segments. Simple bending and multiple bending were evaluated. It is indicated that bent fuse segments are less stiff than straight segments, that the relation between stiffness and amplitude of the bend is an inverse power law with the amplitude to a power much higher than squared, that the decrease of overall stiffness is approximately proportional to the number of bends, and that rectangular or circular bending reduce the stiffness most efficiently, inasmuch as such contours envelop the largest areas on the basis of fixed length.