Siemens Aktiengesellschaft

Joaquin E Bohrdt

Gerhard Grieger

Klaus Schuler

An improved fluid actuating device for an electric switching apparatus such as a high-voltage power circuit breaker or the like includes an actuator for actuating the electric switching apparatus. The actuator has a cylinder and a differential piston movable in the cylinder between first and second end-positions corresponding to the open and closed positions of the switching apparatus. The differential piston has two end-faces for receiving fluid pressure force. One of the two end-faces has a surface area greater than the other one of the two end-faces. A high-pressure fluid supply supplies fluid to the two end-faces and a valve alternately interrupts and passes the fluid from the fluid supply to the one end-face whereby the differential piston is caused to move from the first end-position to the second end-position when the valve passes fluid to act upon the one end-face of the piston. Means are provided for reducing the quantity of the fluid supplied to the one end-face in the course of the movement of the differential piston to the second end-position from the first end-position and before the second end-position is reached.

Fluid actuating device for an electric circuit breaker

An improved reversing valve for use in hydraulic actuators of electric high-voltage circuit breakers wherein the valve is of the type comprising: a ball for controlling the path to be reversed; means for continuously subjecting the ball to a pressure force; a movable plunger for loading the ball; a valve body for controlling the path to be reversed connected to the plunger; and a hydraulically movable piston connected to the plunger. The improvement comprises placement of the ball in a first stable end position by the continuous pressure force and the further inclusion in the valve of a roller toggle means responsive to the loading of the ball by the plunger for causing the continuous pressure on the ball to be reduced and the ball to be placed in a second stable condition.

Reversing valve

Apparatus for controlling the drive for an hydraulically actuated high voltage power circuit breaker is disclosed. More particularly, the apparatus includes a number of position signal transmitter means each associated with a different one of the circuit breaker contact units. These means are each connected to respective freewheel clutches which are connected to the actuating member of a control switch means. The latter switch means is constructed so that it provides off commands to the breaker units only when all the transmitter means connected thereto are in an on or off position. The switch means is also continuously biased toward an off condition with the force of an energy accumulator.

Apparatus for controlling the drive for hydraulically actuated

A fluid actuating device for an electric switching apparatus such as a high-voltage power circuit breaker or the like includes an actuator for actuating the switching apparatus. The actuator in turn is made up of a cylinder and an actuator differential piston movable in the cylinder between positions corresponding to the open and closed positions of the switching apparatus. A fluid supply provides fluid under high-pressure to the end-faces of the actuator differential piston. A main-valve arrangement includes a main-valve differential piston movable for alternately interrupting and connecting fluid from the fluid supply to one of the end-faces of the actuator differential piston whereby the actuator differential piston is caused to move between its end positions. The main-valve differential piston also has end-faces fluidly connected to the fluid supply. A control valve arrangement includes a control differential piston which interrupts and connects the fluid supplied to one of the end-faces of the main-valve differential piston thereby actuating the same. A control arrangement actuates the control differential piston in response to inputs for opening and closing the switching apparatus. The main-valve differential piston and the control differential piston are actuable exclusively by the pressure of the fluid from the fluid supply and this enables the two last-mentioned pistons to maintain their end positions independent of the instantaneous value of the pressure of the fluid.

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Berlin, Germany

Joaquin E Bohrdt