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:
Dec. 23, 1986
Filed:
May. 28, 1985
Dietrich E Herrmann, Vechelde, DE;
Detlev Abraham, Berlin, DE;
Otis Elevator Company, Farmington, CT (US);
Abstract
A variable-frequency, variable-voltage (VVVF) converter is interposed in the line between an AC source and an asynchronous escalator motor. Current to the motor is sensed to determine load in conjunction with a passenger detector and load simulating electronic system and the frequency and voltage of the converter are automatically adjusted in response thereto to control escalator speed. The system includes a converter to supply the asynchronous drive motor of the escalator with variable frequency and an appropriate control circuit for manual or automatic operation of the escalator at different speeds, which is equivalent to different motor frequencies.