Compressed gas-blast circuit breaker

Abstract

A compressed gas-blast circuit breaker including a pump cylinder which is moved along with a movable first contact piece. The pump cylinder surrounds a pumping space and a blast chamber, the latter of which is fluidly connected to a first blast nozzle surrounding the first contact piece. A pump piston is supported on a fixed support part via toggle levers, and a toggle joint of the toggle levers is pivoted to a drive rod via a rocker. At the start of a switch-off stroke, an initial bent position of the toggle lever is lessened, intensified after the straightened position has been passed, then lessened again and intensified again after the straightened position has been passed once more. The oscillation of the toggle lever about the straightened position permits the pump piston to be virtually stationary, while an intermediate bottom, which separates the pumping space from the blast chamber, approaches the pump piston in order to reduce the pumping volume. As a result, arc extinguishing gas is pumped into the blast chamber through a nonreturn valve from the pumping space in order to generate blast pressure. Subsequently, the pump piston is moved in the same sense as the pump cylinder until the switched-off position is reached. The pump piston is positively guided during switching off and also during switching on.