Control apparatus for escalator
US4748394A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 17, 1986 |
| Grant date | May 31, 1988 |
| Priority date | — |
| Expiry date | Jun 17, 2006 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66B25/00
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A control apparatus for an escalator wherein a low speed operation is performed in the absence of passengers at the escalator, and a high speed operation is performed in the presence of passengers at the escalator the alternating current of a three-phase A-C power source is converted by frequency conversion means into a three-phase alternating current of low frequency, with which an induction motor is energized to perform the low speed operation, so that the induction motor is rotated near a synchronous speed corresponding to the low frequency, to realize the low speed operation of high efficiency. Moreover, when passengers have been detected, the frequency of the alternating current from the conversion means is gradually raised, and the conversion means is thereafter switched to the three-phase A-C power source upon detecting the synchronism of this alternating current with the alternating current of the three-phase A-C power source, so that smooth switching free from shocks becomes possible.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.