Switch over from the mains supply to a frequency converter by a phase correction process for an escalator drive

US6634463B2 · kind B2 · utility

Assignee

• OTIS ELECATOR COMPANY · US

Inventors

• Stefan Spannhake · Berlin, DE
• Michael Mann · Berlin, DE
• Gunter Blechschmidt · Berlin, DE
• Peter Walden · Berlin, DE
• Robert Oesterle · Berlin, DE
• Michael Bernhard Kocur · Berlin, DE

Key dates

• Filing date: May 16, 2002
• Grant date: Oct 21, 2003
• Expiry date: May 16, 2022

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B66B25/00
• WIPO field: Handling
• WIPO sector: Mechanical engineering

Abstract

Method for controlling the drive of a conveyor device (10), especially in the form of an escalator or moving sidewalk, switchable between load operation and no-load operation, having a drive motor (26) and a frequency changer (42) controllable at least with respect to frequency and phase position of its output voltage, in which the drive motor (26) 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.