Status of joint development and research on noise frequency induction

The work of finding out the technical facts bearing on the problems of the physical relations of power and telephone circuits was intrusted to the Joint Subcommittee on Development and Research of the National Electric Light Association and the Bell System. This paper has to do with this fact-finding work so far as it concerns noise frequency induction. The work on inductive coordination may be classified into three groups of factors: 1. Influence factors which concern the characteristics of the power circuits. 2. Susceptiveness factors which concern the characteristics of the communication circuits. 3. Coupling factors which concern the interrelation of power and communication circuits. The paper discusses these various factors in detail and describes the work done by the committee or in progress regarding them. References are given to published reports and papers which present the results of technical studies already completed. Many of the existing noise frequency induction problems have arisen because of the development of the art of the two industries without such close cooperation between them as now exists. It is becoming evident, from the work of this Joint Subcommittee, that while it is not practicable to design machinery and apparatus for power systems to be entirely free of harmonics, or to ideally balance either power or telephone circuits, it is possible to control these factors within limits which, in conjunction with the control of coupling obtainable by cooperative planning of routes and coordination of transpositions, permit satisfactory operation of both services without unduly burdening either.