Discussion on “regeneration of power with single-phase electric railway motors“, at Niagara Falls, N. Y., June 28, 1907

The possibility of regenerating power with single-phase motors is one of the valuable features of the single-phase system and one which will be of great assistance in bringing the motor into the field of heavy railway work. The possibility of regenerating at various speeds is well illustrated in Mr. Cooper´s paper, but it is interesting to note that there are two points in the system at which the speed can be varied; first, by changing the tap on the transformer from which the exciting motor obtains its excitation; secondly, by changing the tap on the transformer to which the generating motors are connected. These two actions may be independent, giving twice as many steps as there are taps. With this arrangement a very large number of taps on the transformer is not necessary.