Long-time operation of high breaking capacity fuses

The long-time operation of a high breaking capacity fuse using notched strip elements and M-effect alloy, is governed by the interrelationship between the element current distribution, the corresponding element temperature distribution and the M-effect diffusion rate. The authors describe a method developed to model these complex effects, and hence determine fuse pre-arcing behaviour. The method is based on modelling both temperature and diffusion as electrical analogues and the utilisation of a computer circuit analysis software package to simulate the resulting circuitry. The model enables fuse parameters to be studied to depths previously not possible, and offers considerable possibilities in the fields of fuse design and fuse applications.