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:
Oct. 21, 2003
Filed:
May. 16, 2002
Stefan Spannhake, Berlin, DE;
Michael Mann, Berlin, DE;
Gunter Blechschmidt, Berlin, DE;
Peter Walden, Berlin, DE;
Robert Oesterle, Berlin, DE;
Michael B. Kocur, Berlin, DE;
Otiscelecator Company, Farmington, CT (US);
Abstract
Method for controlling the drive of a conveyor device ( ), especially in the form of an escalator or moving sidewalk, switchable between load operation and no-load operation, having a drive motor ( ) and a frequency changer ( ) controllable at least with respect to frequency and phase position of its output voltage, in which the drive motor ( ) in load operation is fed with a line voltage with essentially constant line frequency and in no-load operation with the frequency changer output voltage, the phase difference between the phase position of the line voltage and the phase position of the frequency changer output voltage is determined, the phase position of the frequency changer output voltage is corrected according to the determined phase difference and therefore essentially brought into agreement with the phase position of the line voltage and switching is produced as soon as this agreement is reached.