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:
May. 24, 1988
Filed:
Apr. 01, 1987
Applicant:
Inventor:
Tooru Tanahashi, Inazawa, JP;
Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B66B / ; H02P / ;
U.S. Cl.
CPC ...
187119 ; 318801 ;
Abstract
A speed control apparatus for an A.C. elevator according to this invention comprises integration circuits which integrate outputs of current detectors for detecting primary currents of an induction motor and which are reset at fixed periods, and holding circuits which hold outputs of the integration circuits for a predetermined time. Thus, the influences of the ripples of the currents by pulse width modulation are eliminated, and the digital conversions of the three-phase currents can be performed by a single analog-to-digital converter.