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. 19, 1988
Filed:
May. 06, 1987
Applicant:
Inventor:
Hiroyuki Ikejima, Inazawa City, JP;
Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B66B / ;
U.S. Cl.
CPC ...
187119 ; 318806 ;
Abstract
A control apparatus for an A.C. elevator having a variable voltage and variable frequency inverter for driving an induction motor coupled to a cage of the elevator, a control device for controlling the inverter in accordance with a deviation between a speed signal detected from the induction motor and a speed command signal having a preset value, and an abnormality detection device for interrupting feed of the A.C. power to the induction motor upon detecting that a slip frequency command corresponding to the deviation is greater than a predetermined set value and continues exceeding the predetermined set value in excess of a predetermined period of time.