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. 27, 1998
Filed:
May. 10, 1995
Seppo Suur-Askola, Riihimaki, FI;
Ralf Ekholm, Helsinki, FI;
Kone Oy, Helsinki, FI;
Abstract
The invention relates to an apparatus for regulating the speed of an a.c. elevator motor (10) by means of a frequency converter (8) consisting of a rectifier bridge (12) and an inverter bridge (14) with an intermediate circuit between them. The frequency of the frequency converter is adjusted until it corresponds to a frequency reference (f.sub.ref) corresponding to the speed reference (v.sub.ref,v.sub.ref ') of the motor. The velocity of the motor (v.sub.real) is measured to form a speed feedback signal. According to the invention, the apparatus has elements (24,26) for correcting the speed reference (v.sub.ref) on the basis of the change occurring in the voltage (U.sub.c) of the intermediate circuit.