THE APPLICATION OF CONTROLLED STATIC CONVERTERS IN TRACTIVE UNITS

Publisher Summary This chapter discusses various advantages offered by the application of controlled static converters, mainly in a.c. traction, including the problems encountered with various circuits. The conventional direct-motor drive, that is, the traction motor fed directly from the power supply system through appropriate controls and regulators for speed and tractive force, meets the traction requirements to a fairly high degree. The electric drive should be designed for low maintenance requirements and accessibility to those parts requiring periodic maintenance. The interference of the electrical system with the signaling, telecommunication, and power station installations should require but minor alterations in the fixed installations. The time-honored steam engine already allowed a continuous control of the tractive effort, except for a certain unbalance in the piston forces, and so do the modern diesel locomotives with electric or hydraulic transmission of torque. For the conventional direct-motor fed with a.c. or d.c. from the catenary, the control of the tractive force required a considerable effort that resulted in a quasi-continuous control only. The steps are quite noticeable, even in modern direct-motor designs.