Gas-blast circuit breaker

Abstract

In a gas-blast circuit breaker, compressed gas is directed through a movable contact maker into a blow-out space, the latter being delimited by a cylinder and a piston which is operatively associated with the movable contact maker. The piston comprises inlet openings which are releasably closed by means of a valve body. At a neck or collar of the piston there is displaceably mounted an actuating element, the latter being reciprocatingly movable between a lower first lock-in position and an upper second lock-in position. The actuating element comprises a nose or lug which, during the closing operation, abuts against an upper stop face or surface, whereby the actuating element is brought into the lower first lock-in position. The valve body thereby moves into the closed position thereof. Towards the end of the opening stroke, a shaft associated with the actuating element comes to bear upon a lower stop face or surface, so that the actuating element is brought back to the upper second lock-in position thereof, whereby the valve body is returned to and retained in its open position. The blow-out space is thus connected with the ambient space during the closing operation and again separated from the ambient space prior to the opening or tripping operation. The driving mechanism of the circuit breaker is assisted during the interruption of relatively high-amperage currents and no additional driving effort is required of the driving mechanism during the closing operation and the interruption of relatively low-amperage currents. The gas-blast circuit breaker thus gets by with a driving mechanism of relatively low operating power.