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AssigneePlateformes et Structures Oceaniques
InventorGilles Gazel-Anthoine
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A control device for lifting winches, in particular for drilling rigs, uses an electric motor able to operate in all four quadrants of the torque-speed diagram. A control circuit procures controlled excitation of the electric motor. A manipulator on a control panel controls the control circuit by establishing, according to its position, a given speed request instruction. An indexing circuit for controlling the control circuit is adapted, on the bases of predetermined end of travel positions and a given law relating the speed to the difference in height between a given end of travel position and the actual height at the time in question, to establish a given speed request instruction. A comparator passes to the control circuit only the speed request instruction that it receives representing the lower speed.
Control apparatus for lifting winches for drilling rigs for raising and lowering a travelling block and a string of drilling pipes, comprising an electric motor operable in all four quadrants of a torque-speed diagram, control means for controlling excitation of said electric motor, an operator control panel, speed selector means associated with said operator control panel and operably connected to said control means for selecting and generating a first speed request instruction, an indexing circuit for controlling the motor control means, the travelling block having predetermined end-of-travel positions, said indexing circuit being responsive to a relationship of the speed of the electric motor as a function of the distance between one of the end-of-travel positions and an instantaneous travel position of the travelling block to calculate a second speed request instruction, a comparator for comparing the first and second speed request instructions and delivering the lower of the speed request instructions to said control means.
Dependencies are inferred from the claim text.