Abstract :
The principal applications of the current locus of single-phase induction motors are the predetermination of the performance of a projected motor on the basis of its constants, and the determination of the performance and constants of an existing motor on the basis of a few simple tests. The first question is particularly attractive to a mathematically trained mind, because, with constants considered as known, it is simply a problem of mathematics; a great amount of work has been done to find and perfect its solution. The second problem is, perhaps, more difficult than the first. Its thorough treatment requires not only the knowledge of the solution of the first problem, but also the ability to make use of more or less complicated combinations of constants given by tests instead of the constants themselves; moreover, the exact solution usually cannot be obtained, and one is obliged to make certain incorrect assumptions, drawing upon the practical experience to set proper limits to these inaccuracies; for this reason, perhaps, the second problem has always been less popular with investigators than the first, and the available results still leave room for improvement, especially in connection with the “tilted” diagram. In what follows this problem is treated by a method which is believed to combine the accuracy with comparative simplicity of the final results — the latter, at least, to the extent which can reasonably be expected when dealing with an apparatus of such inherent complexity as the single-phase induction motor.
