The Circle Diagram of the Polyphase Brush-Shifting Commutator Motor (Schrage Type)

This paper presents a derivation of the circle diagram and performance formulas of the polyphase brush-shifting motor (Schrage type). Using similar assumptions as required for the derivation of the Heyland circle, a simple diagram is developed, which permits the graphical determination of current, power factor, output, slip, and copper losses of the machine. Design formulas are given.