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:
Sep. 30, 2003
Filed:
May. 15, 2002
Reinhard Henkel, Berlin, DE;
Stefan Spannhake, Berlin, DE;
Ralph Stripling, Berlin, DE;
Richard Markus, Minden, DE;
Otis Elevator Company, Farmington, CT (US);
Abstract
A method of controlling the drive of conveyor installation which includes a drive motor ( ) and a frequency converter ( ) whose output is adjustable, between a load operation and an idle mode, in the form of an escalator ( ) or a moving sidewalk, where: in the load operation mode drive motor ( ) is supplied with a line voltage at an essentially constant line frequency (f ), and in the idle mode with an output voltage of the frequency converter ( ); the line voltage and the frequency converter's output voltage are compared with respect to frequency and phase position; the frequency converter ( ) is set for an output frequency which has a predetermined spacing (&Dgr;f , &Dgr;f ) from the line frequency (f ); a demand to switch modes is signalled by a conveyance signal generator ( ); and at the point in time (t , t ), after a demand to switch modes has been signalled, when the output frequency of the converter ( ) has reached the predetermined frequency spacing (&Dgr;f , &Dgr;f ) from the line frequency (f ), and a predetermined phase spacing has been achieved between the frequency converter's output voltage and the line frequency (f ), a switch-over signal ( ) is emitted to switch the drive motor ( ) between the frequency converter supply and the line supply.