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:
Jun. 18, 2002
Filed:
May. 19, 2000
David J. Gritter, Wauwatosa, WI (US);
Dora Yuan Wang, Shanghai, CN;
Eaton Corporation, Cleveland, OH (US);
Abstract
A method is provided for controlling a three-phase, AC induction motor. Each phase of the AC induction motor is connected to an AC input source by a thyristor switch and a bypass contactor connected in parallel in order to provide voltage and current to the AC induction motor. The method includes the steps of sequentially firing pairs of thyristor switches at a predetermined initial alpha firing angle. A new alpha firing angle is calculated which is dependant upon the initial alpha firing angle. Thereafter, pairs of thyristor switches are fired at the new alpha firing angle. The new alpha firing angle is provided as the initial alpha firing angle and a new alpha firing angle is calculated. The process is repeated until the AC induction motor reaches its full operating speed.