Patent ID: 11916497

Abstract:
A frequency converter device (the present invention) is disclosed for controlling the speed of a single-phase asynchronous motor wherein the controlled rotational speed keeps the slip between the speed of a driving rotating magnetic field and a speed of a rotating motor rotor smaller than prior art. Two voltages (Vaux and Vmain) with independent amplitudes, an approximate 90° phase shift relative to each other, and a common frequency are provided by the frequency converter device from a single AC or DC supply voltage. By independently adjusting the amplitudes of said voltages Vaux and Vmain on the motor windings, a greater current can flow at lower frequencies than is possible with the prior art with the rising reactance (at lower frequencies) of its capacitor, and the higher current results in greater torque. The ability to lower the RPMs with more torque to the motor rotor results in less slip than the prior art and thus increases efficiency.