METHOD AND DEVICE FOR CONTROLLING THE SPEED OF INDUCTION MOTOR

摘要

The method and the device are applied in the creation of conventional systems for electric start of lifting-transporting, textile, instrumental and other machines. They enhance the reliability in speed regulation, while the device is simplified. The method transforms a series of rectangular impulses with a sixfold higher frequency from that of the network to get three-phase systems untapping impulses that ensure the charging of stator coils with a system for periodic three-phase voltages, while the frequency of the first harmonics is n-times as small than the frequency of the network.