| 摘要 |
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 electric switching apparatus. The actuator includes a cylinder and an actuator differential piston movable in the cylinder between first and second positions corresponding to the open and closed positions of the switching apparatus. The actuator differential piston has two end-faces for receiving fluid pressure force and one of the end-faces has a larger surface area than the other one of the end-faces. A pressure fluid supply supplies fluid under pressure and is connected to the actuator for continuously supplying fluid under pressure to the other one of the end-faces. A switching-valve alternately interrupts and connects the fluid from the pressure fluid supply to the one end-face of the actuator differential piston whereby the actuator differential piston is caused to move between its first and second positions. A control valve includes a valve member movable between first and second end-positions for respectively interrupting and connecting the fluid from the pressure fluid supply to the switching-valve for actuating the same. A spring is arranged to spring-load the valve member at the first end-position. The valve member can be moved from the first end-position to the second end-position against the force of the spring by suitable mechanical or fluid means. A latching mechanism is connected to the control valve for latching the valve member in the second end-position whereby the actuator differential piston is held in the second position against the fluid pressue force applied to the other one of the end-faces thereof. |
