The Voltage across a Fuse during the Current Interruption Process

Results of experiments with fusing wires are discussed and explained theoretically. Multiple arcing is observed; it is explained in a thermodynamic model. Also, the possible absence of multiple arcing at high currents is explained. There, evaporation of superheated fuse material causes the fast increase of the fuse resistance. This evaporation explains the experimentally observed behavior of the fuse resistance as a function of fuse diameter, whereas the concept of multiple arcing fails to do so. Results from experiments confirm energy balance equations, both for fuses in air and for fuses embedded in fine-grained sand. The energy balance equation for the latter case is shown to be equivalent to Mayr´s equation.