US 4,118,613 AGranted

Hydraulically-actuated operating system for an electric circuit breaker

AssigneeGeneral Electric Company

InventorsPhilip Barkan, Imdad Imam

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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 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 vent is located hydraulically between the actuating space and the valve for affording communication between said actuating space and a low pressure region. Flow control means is provided for restricting leakage through said vent to a rate that prevents said leakage from substantially detracting from the development of pressure within said actuatng space during the period from initial opening of the valve to the time when said piston has moved through most of its opening stroke. Following such period and while the valve is still open, said flow control means allows effective leakage through said vent. The accumulator has 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 said vent after the piston has moved through a circuit-breaker opening stroke and while the valve is in its open state. Means is provided for resetting the valve to its closed state in response to said pressure decay in the actuating space.

Claims18

Dependent claims

In a hydraulically-actuated operating system for an electric circuit breaker,

(a) a fluid motor comprising a cylinder and a movable piston adapted to move in an opening direction within said cylinder to open said circuit breaker and in a reverse direction within said cylinder during closing of said circuit breaker,
(b) an accummulator for supplying pressurized liquid to a piston-actuating space within said cylinder,
(c) 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,
(d) 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,
(e) 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,
(f) 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 said vent shortly after said piston has moved through a circuit-breaker opening stroke and while said movable valve member is in its valve-open position, and
(g) means for restoring said movable valve member to its closed position in response to said pressure decay in said actuating space.

4 more elements

In a hydraulically-actuated operating system for an electric circuit breaker,

(a) a fluid motor comprising a cylinder and a movable piston adapted to move in an opening direction within said cylinder to open said circuit breaker and in a reverse direction within said cylinder during closing of said circuit breaker,
(b) an accumulator for supplying pressurized liquid to an actuating space within said cylinder,
(c) a normally-closed main 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 main valve comprising a movable main valve member that is movable from a valve-closed to a valve-open position to open said main valve and is returnable to said valve-closed position to close said main valve,
(d) a vent located hydraulically downstream of said main valve with respect to said accumulator for affording free communication between said actuating space and a low pressure region when said main valve is closed,
(e) an auxiliary valve member coupled to said movable main valve member and arranged to restrict flow through said vent when said movable main valve member is moved into its valve-open position, thereby accelerating pressure build-up within said actuating space,
(f) said auxiliary valve member allowing a limited amount of leakage through said vent when said movable main valve member is in its valve-open position,
(g) 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 leakage through said vent shortly after said piston has moved through a circuit-breaker opening stroke and while said movable main valve member is in its valve-open position, and
(h) means for restoring said movable main valve member to its closed position in response to said pressure decay in said actuating space, thereby restoring free communication through said vent between said actuating space and said low pressure region.

5 more elements

Dependencies are inferred from the claim text.