Proximity effect in wires and thin tubes

Formulas are given, with examples, for the following new problems in proximity effect resistance ratio: Thin Tube and Infinitesimal Wire; Two Thin Tubes in Return Circuit; Two Thin Tubes in Parallel; Insulated Cable Sheaths in Single-Phase Circuit; Cable Sheaths in Three-Phase Circuit, Flat Spacing; Finite Wire and Infinitesimal Wire; Two Wires in Parallel; Three-Phase Circuit, Triangular Spacing, Three-Phase Circuit, Flat Spacing. Reduction formulas for Bessel functions, suitable for skin effect problems, are tabulated, and a table of values of the first five orders, for use in drawing curves, is given.