Circle Diagrams for Synchronous Motors

The students mind is usually curious. We had worked with circle diagrams for several different kinds of equipment, and all that we worked with, except that for a synchronous motor, included all the losses incurred in operating the piece of equipment. Since there was only one exception, we decided to determine the difficulties incurred in applying the circle diagram to all of the losses of the synchronous motor. As this could not be accomplished by any theoretical method that we tried to work out, we resorted to the trial and error method. We made a complete test of the synchronous motor and then found the equivalent diagram to fit the experimental results as near as possible. The intention of this paper is to show how we adopted an equivalent diagram to the experimental results, what the errors are in our assumptions, and the magnitude of these errors.