Formulas for calculating short-circuit forces between conductors of structural shape

THE mechanical forces acting on busbar supports during short circuit are determined both by the magnitudes of the mutual electromagnetic forces exerted among the bus conductors and by the elastic properties of the supporting structure: its motional resistance, natural frequencies, and physical nature and arrangement. Comprehensive mathematical studies, ∗∗ substantiated by experimental data, of the individual and collective effects of these factors and general methods for calculating the magnitudes involved have been advanced by Schurig and Sayre, 1 Dahlgren, 2,3 and Pilcher. 4 In shorter articles based on the work of the first-named Schurig, Fricke and Sayre, 5 Tanberg, 6 Specht, 7 Edson, 8 and others 9 have presented certain charts, nonograms, and short cuts that facilitate the numerical labor incident to actual calculation.