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:
Oct. 04, 1977
Filed:
Dec. 29, 1975
Applicant:
Inventor:
Hiroshi Kamaike, Inazawa, JA;
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B66B / ;
U.S. Cl.
CPC ...
318230 ; 318227 ; 187 / ;
Abstract
In an elevator speed control system, the actual speed signal from an induction motor is subtracted from a command speed signal and then supplied to a nonlinear circuit. The circuit produces an output voltage approximately proportional to the square root of its input voltage. The output voltage is applied to three phase shifters, one for each phase of a three-phase system, to produce firing signals to control the conduction of associated thyristors resulting in the control of a three-phase voltage applied to the motor and therefore its rotational speed.