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:
Jan. 08, 1991
Filed:
Apr. 18, 1989
Applicant:
Inventors:
Kazuhiko Doi, Narita, JP;
Yasutami Kito, Tokyo, JP;
Assignee:
Otis Elevator Company, Farmington, CT (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B66B / ;
U.S. Cl.
CPC ...
187119 ; 318803 ;
Abstract
In an elevator provided with an inverter driven induction motor, output torque is determined by direct current of an inverter, slip frequency is determined from the thusly determined torque, the gap between an open-loop dictated speed pattern and the actual speed is compensated by the slip calculated during acceleration and constant speed movement, so that the open-loop control may be improved in terms of stop position precision.