Abridgment of auxiliary circuits for high-voltage D-C. Motor car equipments

The increasing demand for frequent and rapid transportation on both suburban and other railways has brought to the fore the multiple unit motor car. The steps taken in the development of the auxiliary equipment for the multiple unit motor coach are quite interesting, and have been made the subject of this paper. The first part of the paper is devoted to cars equipped with apparatus for converting the high-voltage d-c. overhead-line current to the voltages required for operating standard auxiliary equipment. The second part is devoted to auxiliary equipment suitable for operation on the higher d-c. voltages now being used in more and more electrification projects. Although this paper refers mostly to development work carried out in Europe, it is nevertheless believed to be of interest to American engineers as the basic principles underlying this development are also applicable to American multiple unit cars.