Abstract: A pneumatic puffer circuit breaker for high tension stations comprises a sealed chamber filled with a highly dielectric gas, a fixed main contact (18, 39) and at least one fixed arcing contact (9, 14, 16) disposed as co-axial cylinders and deliminiting a first volume (12). A fixed blast nozzle (24) delimits in conjunction with the fixed arcing contact an outlet passage (12A) for gas from said first volume (12). A tubular moving main contact (29) and a tubular moving arcing contact (15) are disposed coaxially with each other and with the fixed contacts, and a cylinder (10) is mounted to co-operate with the fixed main contact during circuit interruption to compress the gas in said first volume. Said cylinder has a spring (11) urging it towards a drive member (20, 31) mounted to move with said moving contacts.

Abstract: The invention relates to a compressed gas circuit-breaker with a tubular stationary contact, a tubular moving contact, a device for inserting a resistance when the circuit-breaker closes, the insertion device and the resistance being disposed in a coaxial casing, said device being controlled by the moving contact of the circuit-breaker, the insertion device (19) being of the semi-mobile type and having a first means (51, 52) for damping its closing and a second means (50, 44) for delaying its opening when the circuit-breaker opens, wherein the first means (51, 52) and the second means (50, 44) are of the type which operate by pressure reduction. Application to circuit-circuit breakers which equip very high tension lines.