Abstract :
It is not the object of this paper to argue for single-phase alternating-current electrification versus direct-current electrification, nor to argue for the locomotive versus the multiple-unit system of electric propulsion, nor to argue in favor of the axle motor as against the detached motor with side-bar or gear connections. The sole object of the paper is to discuss the question as to the maximum single-phase series motor rating that can be placed within a given space, and indeed the authors approach this question, not on an absolute basis, but on a basis of comparison. Given a well-designed single-phase alternating-current series motor of the usual construction, as represented, for example, by the motors of the present locomotives of the New York, New Haven & Hartford Railroad (and every one who has seen these motors in operation must admit that they represent a splendid achievement on the part of their designer) the question is how great an increase of rating can be realized by certain alterations in the design and by the use of certain new auxiliary devices. As will appear in the sequel, this question admits of a qualitative answer in every particular and of a quantitative answer in several important particulars.
