Control of an elevator hoisting motor during under voltage conditions in the main power source
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Jul 20, 1993
Grant Date -
N/A
app pub date -
Oct 31, 1990
filing date -
Oct 31, 1989
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A method and an apparatus for the control of an elevator a.c. or d.c. hoisting motor driven by a frequency converter unit, or by a rectifier unit, supplied by a three phase power source is disclosed. The voltage of the mains power source is monitored using a voltage measuring unit. The frequency converter or rectifier is supervised by a control unit which selects a speed reference curve, best suited for a run. The controller unit allows the elevator speed to be varied continuously with the mains voltage so that the elevator always travels at the highest possible speed. When an undervoltage condition is detected in the mains power source, the rotational speed of the hoisting motor is reduced without modifying the acceleration so as to avoid an overcurrent if the rectifier or inverter switches. If, in addition, the acceleration is decreased before the maximum speed is obtained, a higher maximum speed may be obtained for a given low level of supply voltage. The solution offered by this invention enables the elevator system to work at undervoltages as low as 60%.
First Claim
Family
International Classification(s)
Cited Art Landscape
Patent Citation Ranking
Advertisement
Advertisement
Advertisement
Recipient Email Address
Recipient Email Address
Comment
Recipient Email Address
Add to Portfolio(s)
To add this patent to one, or more, of your portfolios, simply click the add button.
This Patent is in these Portfolios:
Add to additional portfolios:
Last Refreshed On:
Changes done successfully