Generalised short-circuit characteristics for h.r.c. fuses

The short-circuit performance of fuses is analysed using simple models to represent prearcing and arcing behaviour. The analysis is developed for both d.c. and a.c. source-circuit conditions, and the resulting equations are normalised by the introduction of a unified per-unit system. From these normalised equations a comprehensive set of generalised fuse characteristics has been prepared. These characteristics can be used for many purposes in fuse design, testing and application, and some examples of their use are given.