Theory of speed and power factor control of large induction motors by neutralized polyphase alternating current commutator machines

Theory of induction motor control, discussing single-range (below synchronism only) speed and power factor control by means of a constant-speed series commutator motor, by means of a constant-speed shunt commutator motor, by means of a constant-speed compound excited commutator motor; double-range (all speeds above or below synchronism) speed and power factor control by means of a constant-speed shunt commutator motor; and double-range (either above or below synchronism) operation remote from synchronism. The discussion is illustrated in detail, special attention being paid to the circle diagram.