Inductive Co-ordination with Series Sodium Highway Lighting Circuits

This paper describes the wave-shape characteristics of the sodium-vapor lamp and discusses the relative inductive influence of various series circuit arrangements in which such lamps are employed. A method is outlined by means of which the noise to be expected in an exposed telephone line may be estimated. Measures are described which may be applied in the telephone plant or in the lighting circuit to assist in the inductive co-ordination of the two systems. These measures need be considered only when a considerable number of lamps is involved, since noise induction is negligible when there are only a few lamps as, for instance, at highway intersections.