Automatic earthing device e.g. for metal-encapsulated gas-insulated load isolating switch - increases pressure rapidly after sparking to activate device by pressure activated trigger mechanism

摘要

An automatic earthing device for load separating circuits is actuated when a spark appears through a pneumatic trigger mechanism. The device and trigger (3-6) are contained in a metal housing (7). When pressure increases rapidly, the trigger (3-6) releases the earthing device to short circuit and earth current bars. The trigger (3-6) includes a pressure detecting piston (5) in a closed cylinder (14) with a vent (14). A lock (4,4') for the trigger (3-6) is movable by the piston (5) via a connection mechanism (6). Contact blade arms (8) are provided on a common rotation axle (1). The axle (1) has an actuator arm driven by a compression spring (2). The axle (1) has a release handle (3) which engages with the lock (4,4') in a first position. When the lock (4,4') moves out of engagement, the device is triggered and the arms (8) rotate to earth the bars via contact blocks (9). USE/ADVANTAGE - For metal-encapsulated, gas-insulated load separating circuits. Operates reliably and quickly when sparks are erroneously generated.