Static Leonard system
US4165801A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1977 |
| Grant date | Aug 28, 1979 |
| Priority date | — |
| Expiry date | Sep 8, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S388/91
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The disclosed Leonard type elevator system comprises a reversible converter for controllably driving a DC motor, and an AC voltage detector and a DC voltage detector connected to the AC and DC sides of the converter respectively for detecting the voltages developed on the respective sides of the converter. When a difference in detected voltage between the two detectors exceeds a predetermined magnitude due to a decrease in the AC source voltage, a comparator produces an output serving to disconnect the DC motor from the converter. Also the comparator may produce such an output when the converter receives regenerative power from the DC motor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.