Abstract :
THE BASIC principle of grid control used in connection with large mercury arc power rectifiers is reviewed briefly in order to explain a new application of rectifiers which was made possible by these improvements. This application is described, and it is shown how by its use a single-phase motor for a-c. railway electrification service with series-motor characteristics and for use on any commercial frequency can be designed. With the grid-controlled rectifier it was found possible to eliminate the commutator of the motor and practically all the expensive controlling, switching, and reversing equipment commonly used on a-c. locomotives. The data and layout of a 1,000-hp., 50-cycle, 15,000-volt, single-phase locomotive are given.
