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:
Mar. 31, 1992
Filed:
Apr. 09, 1991
Applicant:
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B65G / ;
U.S. Cl.
CPC ...
198323 ; 198330 ;
Abstract
An induction motor, which drives an escalator, can be selectively supplied by both a commercial power source and a power converting unit. A control apparatus for the escalator has a trouble detector for detecting the occurence of a trouble or abnormality on the basis of an input and/or output current and/or voltage of the power unit, an actual speed of the escalator, a speed command for the escalator speed and so on. Usually, the motor is fed by the power converting unit, and the power supply thereto is switched over from the power converting unit to the commercial power source, when the trouble detector produces its output representative of the occurrence of a trouble or abnormality.