Performance criteria for current-limiting power fuses — II

THIS PAPER is part of an analytical study conducted for the purpose of establishing a sound fundamental interpretation of observed performance characteristics of high interrupting-capacity power fuses of the current-limiting type. Some of the more important conclusions, which have been verified by a study of test performance, are presented and discussed in the foregoing part of this paper by C. L. Schuck. In another sense this paper is an application of the analytical methods developed in the two papers on “Geometry of Arc Interruption.”^15,16 This application to fuse performance is particularly fitting since the interval from the inception of a short circuit until the arc voltage of the fuse is introduced, may be predetermined quite accurately from the melting characteristics of the fuse. Conductor heating and energy equations are presented for the first time which include all the essential variables to predetermine the arc energy to be developed by the interrupter for various magnitudes of arc voltage, degrees of circuit asymmetry, and melting times of the fuse.