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US 4,387,280 AGranted
High speed hydraulically-actuated operating system for an electric circuit breaker
AssigneeGeneral Electric Company
InventorImdad Iman
Life of this patent
Estimating the term…
Abstract
This hydraulically-actuated operating system comprises a cylinder, a piston movable therein in an opening direction to open a circuit breaker, and an accumulator for supplying pressurized liquid to a breaker-opening piston-actuating space within the cylinder. A normally-closed valve between the accumulator and the actuating space is openable to allow pressurized liquid from the accumulator to flow through the valve into the actuating space to drive the piston in an opening direction. A dashpotting mechanism operating separately from the hydraulic actuating system is provided, thereby reducing flow restriction interference with breaker opening.
Claims12
An hydraulically-actuated operating system for an electric circuit breaker comprising:
- a fluid motor comprising a cylinder, a piston rod and a movable piston mounted on said piston rod and adapted to move in an opening direction within said cylinder to open an electric circuit breaker and in a reverse direction within said cylinder during closing of the circuit breaker;
- an accumulator for supplying pressurized liquid to a piston-actuating space within said cylinder;
- a normally-closed valve located hydraulically between said accumulator and said actuating space and openable to establish communication between said accumulator and said actuating space so that pressurized liquid from said accumulator can flow through said valve to said actuating space to drive said piston in an opening direction, said valve comprising a movable valve member that is movable from a valve-closed to a valve-open position to open said valve and is returnable to said valve-closed position to close said valve;
- a vent located hydraulically downstream of said valve with respect to said accumulator for affording communication between said actuating space and a low pressure region;
- flow control means for restricting leakage through said vent to a rate that prevents said leakage from substantially detracting from the development of pressure within said actuating space during the period from initial opening of said valve to the time when said piston has moved through a substantial portion of its opening stroke, said flow control means acting following such period and while said valve is still open to allow effective leakage through said vent;
- said accumulator having a limited capacity that results in the pressure within said actuating space decaying promptly to a low value as a result of effective leakage through a circuit-breaker opening stroke and while said movable valve member is in its valve-open position;
- means for restoring said movable valve member to its closed position in response to said pressure decay in said actuating space;
- and
- dashpotting means comprising a shaft separate from said piston rod and disposed in axial alignment with said piston and opposite said actuating space, an abutment disposed at one end of said shaft and adapted to engage an end of said piston, and means for retarding motion of said shaft connected to the other end of said shaft, said abutment being axially spaced from said piston such that said piston contacts said dashpotting means abutment after travelling through said substantial portion of its opening stroke;
- said dashpotting means comprising the sole motion-retarding means for substantially retarding motion of said piston in said opening direction.
7 more elements
A method of operating a hydraulically actuated operating system for an electric circuit breaker comprising the steps of:
- pressurizing a supply of a liquid breaker-operating medium disposed within a pressure accumulator;
- supplying an unimpeded flow of said pressurized medium from said accumulator to a breaker-opening space of a fluid motor operably connected to one of the contacts of said circuit breaker through an unimpeded flow path hydraulically connecting said accumulator and said breaker-operating space by opening a valve disposed hydraulically between said accumulator and said breaker-opening space to move a piston rod of said fluid motor and a piston of said fluid motor and mounted on said piston rod in a breaker-opening direction;
- and
- following travel of said piston through a substantial portion of its opening stroke, contacting said piston to an abutment of a dashpotting means comprising a shaft separate from said piston rod and disposed in axial alignment with said piston and means for retarding motion of said shaft connected to said shaft, said abutment being thertofore separated from said piston;
- said dashpotting means comprising sole motion-retarding means for substantially retarding motion of said piston in said breaker-opening direction.
2 more elements
Dependencies are inferred from the claim text.