Silicon Rectifier Locomotive Developments in Europe

After a short historical review of the use of semiconductor junctions as rectifiers, first in control circuits and then in the application to auxiliaries on locomotives and MU (multiple unit) cars, the use of silicon on main power rectifiers on these vehicles in place of ignitrons is examined, especially in France where 50-cycle single-phase electrical traction is now extensively used and is the only system applied on all new lines. After a survey of the new problems which appear in conjunction with the use of semiconductor rectifiers, some of the most recent applications in France are described briefly. Attention is called to the fact that 25 locomotives and MU cars are in service and 182 are in the process of being built. Future uses are diesel-electric locomotives with ac generators and rectifiers, substations for main lines, and silicon-controlled rectifiers (SCRs) for auxiliary functions and main circuits, with the voltage control and the possibility of inverter operation combined in the same equipment for a new prototype locomotive.