Gas-driven power switch with power-assisted piston

A gas-blast circuit-breaker comprising:

• at least one stationary contact member and one moveable contact member;
• a compression device including one actuated compression cylinder that is coupled to the one moveable contact member and one compression piston that is actuated during a breaking movement in the opposite direction to the compression cylinder, whereby the compression cylinder and the compression piston enclose a compression space;
• a mechanical limit stop for restricting movement of the compression piston on a side of the compression piston facing away from the compression space;
• a restoring device connected to the compression piston and pulling the piston rod of the compression piston nearer to the mechanical limit stop;
• a device for reinforcing actuation through the magnetic effect of the breaking current;
• a hollow-cylindrical body surrounding a portion of said at least one stationary contact member and said one moveable contact member, said hollow-cylindrical body having a portion consisting of ferromagnetic material, said ferromagnetic portion having at least one continuous slot that runs parallel to the direction of the breaking current;
• and
• at least one rod consisting partly of ferromagnetic material which is introduced in the longitudinal direction into one of the slots;
• wherein one of the compression cylinder and the compression piston is rigidly coupled to the hollow-cylindrical body and the other of the compression cylinder and the composition piston is rigidly coupled to said at least one rod.