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:
Nov. 25, 1986
Filed:
Feb. 27, 1985
Tooru Tanahashi, Gifu, JP;
Yoshio Miyanishi, Nagoya, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A speed control apparatus for an elevator is so constructed that an operating period of time is limited on the basis of a predetermined current command value or an output from a detector for detecting current to be supplied to an induction motor, thereby to render a load time factor of the induction motor a predetermined value or less and to maintain at or below a permissible value a temperature rise value based on a quantity of heat generated by a winding of the induction motor. Thus, the induction motor is prevented from burning even when the induction motor is operated at low speed in, for example, a manual operation mode for installation, maintenance and inspection, or the like.