Patent ID: 6018133
Filing Date: 2000-01-25
Classification: H01H

Abstract:
A circuit-breaker of the puffer type, comprising a casing filled with a dielectric gas under pressure, and two arcing contacts co-operating with each other, at least one of the arcing contacts being part of a moving contact assembly secured to a drive member and organized to be displaced axially inside the casing between a closed position and an open position on being driven during an opening operation, the moving contact assembly being made up of a first tube co-operating with a second tube that is coaxial with the first tube to define firstly a blast chamber, on one side of a ring connected both to the first tube and to the second tube, and secondly a compression chamber on the other side of said ring, communicating with the blast chamber, and closed by a semi-moving piston, the circuit-breaker being provided with first means for holding the piston stationary during a first portion of the displacement stroke of the moving contact assembly between the closed position and the open position, and with second means for displacing the piston axially with the moving contact assembly during a second portion of the same displacement stroke of the moving contact assembly, wherein the first means for holding the piston stationary comprise a stationary retaining member for locking an abutment arrangement associated with the piston, and the second means for axially displacing the piston comprise an unlocking unlacking member for unlocking said abutment arrangement, which member is associated with the moving contact assembly.