An improvement in the performance of the induction motor can be achieved by the insertion of a series capacitor in the stator circuit. A reduction in the rotor slip at a given load torque is achieved, which yields to an increase in the motor efficiency. The machine stability is highly increased by increasing the machine stability limit (pull- out torque). A high starting torque is achieved by the insertion of a stepped resistor in the rotor circuit of the slip-ring induction motor. In addition, the capacitor- resistor combination can be used for speed control for given torque and speed settings.