The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 30, 1991
Filed:
Sep. 14, 1989
Joseph Vithayathil, San Luis Obispo, CA (US);
Other;
Abstract
An AC machine system, in which the machine has an auxiliary rotating magnetic field, in addition to the main rotating field, with different speeds of rotation. The auxiliary field serves to induce AC voltages in the rotor windings, even when the machine is rotating at the synchronous speed of the main field. The induced AC is rectified, by having a rectifier circuit on the rotor, and provides DC excitation, to create fixed magnetic poles on the rotor. Thereby the machine functions at the synchronous speed of the main field, without the need for a DC exciting source, external to the rotor circuit. The presence of AC current components in the rotor coils, enable torque production at non-synchronous speeds also. The combination of main and auxiliary rotating fields can be implemented in several ways, such as a stator supply having more than one frequency components, or components of opposite sequence. It can also be done by appropriate design of the stator circuit.