Proximity effect in a seven-strand cable

THE calculation of the alternating current resistance ratio due to skin effect or proximity effect has been worked out for many shapes and combinations of conductors but often without recourse to experimental results. It is, accordingly, the purpose of this work to check calculations with tests for the type of calculation recently developed, covering the losses in several round wires connected in parallel, of which the arrangement is such that unequal currents flow in the different wires. The experimental results with which the calculated results are to be compared are those presented by A. E. Kennelly and H. A. Affel² in 1916 for seven-strand cables. Their work covered radio frequencies up to 100,000 cycles in rather small conductors. The derivations as presented here are applicable to all frequencies and sizes of conductors.