An excellent speed control method for parametric induction motors

A new speed control method of parametric motor is explained in the paper. The excellent features of the method proposed here are as follows: (1)The constant maximum torque independent of the supply frequency was obtained. (2)Overload protection exists in the parametric motor. (3)The construction of control circuit is simple. (4)Low cost power supply can be designed. (5)Without opening the main circuit, the rotational direction is easily changed electrically. Consequently, the high reliability system and the maintenance free system can be constructed by applying the parametric motors for factory automation, office automation etc.