Abstracts of Technical Articles from Bell System Sources (01 October 1937)

Jour, of Applied, Physics, June 1937. Jour. Acous. Soc. Amer., July 1937. Electrical Engineering, September 1937. 578 ABSTRACTS OF TECHNICAL ARTICLES 579 The locations for the tests were selected to provide a reasonably large range of earth resistivity; also, at one location it was known that the earth structure departed substantially from uniformity. At each of these locations d.-c. transient coupling tests were performed in which transient currents, approximately of the form encountered during faults on d.-c. railway electrifications, were produced in an earthreturn circuit, herein referred to as the primary, and measurements were made of the resultant voltages in earth-return circuits, herein called secondary circuits, parallel to and at separations from the primary circuit of from 50 or 60 to 2,000 feet. 

In addition to the d.-c. transient tests, measurements were made at each location of the steady state a.-c. coupling, in magnitude and phase angle, over a range of frequencies from 20 or 30 cycles to 3,200 cycles. From these a.-c. measurements the transient voltages were computed for a number of cases by evaluating the Fourier integral. The results of the a.-c. coupling tests were useful also in helping to explain, in a general way, the departures of the measured transient voltages from the voltages computed for uniform earth resistivity. T h e measured transient voltages and voltages computed (1) from the a.-c. coupling measurements and (2) on the basis of a uniform earth resistivity, are shown for several representative cases in figures accompanying the paper.