Abstract: A puffer-type gas-blast circuit-breaker comprises an interrupting unit mounted in a housing filled with an insulating gas of high dielectric strength such as sulfur hexafluoride. The interrupting unit includes a main circuit having a pair of stationary and movable main contacts, and an arcing circuit having a pair of stationary and movable arcing contacts. An operating mechanism comprises a control rod coupled to the movable contacts so as to open the main contacts before the separation of the arcing contacts. A pair of input and output terminals extend out of the housing, and a shunt conductor is arranged in the arcing circuit between operating rod and the lower terminal. The longitudinally extending main and arcing circuits are connected in parallel to the terminals and form two independent current paths which are cross-wise spaced inside the housing.

Abstract: An arc-extinguishing device comprising two pairs of contacts having ring-shaped paths and connected electrically in series. A magnetic blow-out coil connected in parallel at one pair of contacts produces a radial magnetic field which causes rotation of the arcs along the ring-shaped paths.