Traction power and chopper harmonics in a rapid transit system

This paper presents harmonic data applicable to 6- and 12- phase rectifier systems and propulsion control choppers used in present-day rapid transit systems. It also outlines the method of predicting the effect of harmonic interference on the performance of audio-frequency signaling systems used on the rapid transit systems for train detection and cab signaling. Until recently, detailed data on the nature and magnitude of harmonics from the traction power rectifier systems and choppers have not been available. Recent tests conducted by the authors and others