Apparatus for controlling a hydraulic elevator
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United States of America Patent
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Sep 7, 1993
Grant Date -
N/A
app pub date -
Oct 15, 1991
filing date -
Oct 16, 1990
priority date (Note) -
In Force
status (Latency Note)
Importance
Abstract
An apparatus for controlling a car of a hydraulic elevator by variable-speed-driving an electric motor directly coupled to a hydraulic pump so as to adjust the rate at which oil is supplied from the hydraulic pump to a hydraulic jack system, the apparatus having a speed controller for variable-speed-driving the electric motor, a first detector for detecting the speed of the car, a second detector for detecting the rotational speed of the electric motor, a third detector for detecting a pressure in the hydraulic jack system, a feedback circuit for returning a control signal for limiting vibration of the car as a feedback signal to the speed controller. The feedback circuit forms the control signal from a differential signal representing the difference between a car speed value converted from the rotational speed of the electric motor detected by the second detector and the car speed detected by the first detector and a pressure signal representing the pressure detected by the third detector.
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