Abstracts of Technical Articles from Bell System Authors (01 October 1940)

Proc. Avier. Wood-Preservers' Assoc., 1940. 2 Jour. Acous. Soc. Amer., July 1940. 3 Electrical Engineering, July 1940. 1 647 648 ' BELL SYSTEM TECHNICAL JOURNAL and communication facilities are in proximity, electromagnetic induction from the power system may cause disturbances in the communication system. 

The avoidance or minimizing of such disturbances, with due regard to the service and other needs of both systems, is a problem of coordination, which is conveniently divided into two parts, one dealing with low-frequency inductive coordination and the other with noise-frequency coordination. The present paper undertakes a general examination of the problem of low-frequency inductive coordination in the light of developments during the past decade. The situation as it existed at the beginning of the decade is to be found well set forth in a paper presented in 1931 at the A.I.E.E. winter convention by R. N. Conwell and H. S. Warren. 

The present paper, like its predecessor, derives from the work of the Joint Subcommittee on Development and Research of the Edison Electric Institute and the Bell System. It is largely concerned with induction from currents due to power system ground faults and the transients which accompany such faults. It gives relatively little attention to continuous low-frequency effects since, up to the present at least, such effects have not been a primary concern in the low frequency coordination of commercial power circuits and Bell System communication circuits.