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. 02, 1986
Filed:
Feb. 26, 1985
Tooru Tanahashi, Gifu, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
In an elevator speed control apparatus wherein an output signal of a speed detector is sampled at a predetermined interval, and an output signal obtained by processing the sampling is applied to an inverter so as to perform a slip frequency control of an induction motor; correction means to receive the speed detector output signal sampled at the predetermined interval, to differentiate it to generate a differential signal and to deliver the differential signal as a correction signal is provided, so that a magnitude by which a rotational speed of the induction motor changes after the output signal of the speed detector has been fed into a microcomputer until the control signal is applied to the inverter is corrected, whereupon the signal for the speed control is delivered to the inverter, thereby to correct the lag of speed detection attributed to the sampling control.