Abstract: The present disclosure relates to a circuit breaker having a compact contact assembly structure, including a stationary portion; and a movable portion to be contact with or to be separated from the stationary portion, wherein the movable portion includes a puffer cylinder configured to temporarily store a compressible fluid; a moving main contact assembled to an end of the puffer cylinder; and a moving nozzle inserted into the moving main contact, and the moving main contact includes an internal protrusion protruded in a radial direction and separated in a circumferential direction from an inner surface thereof, and the moving nozzle includes an external protrusion protruded in a radial direction and separated in a circumferential direction on an external surface thereof, and the internal and external protrusions are alternately coupled to the puffer cylinder, respectively, by a fastening member along the circumferential direction.

Abstract: In a tank type vacuum circuit breaker in which each of movable side and fixed side connection terminals of a vacuum interrupter arranged in a main tank and the lower end of each of conductors of a pair of bushings arranged in a standing condition in the main tank are connected by a flexible conductor and a shield for surrounding connection portions is provided, the shield is configured by combining: a main body side shield which is provided on axial both sides of the vacuum interrupter and covers a connection portion of the flexible conductor and the connection terminal; and a bushing side shield which is provided on the lower end side of the conductor and covers a connection portion of the conductor and the flexible conductor.

Abstract: A power circuit breaker unit has first and second arcing contact pieces. A contact gap is formed between the arcing contact pieces. A switch gas channel of the circuit breaker unit joins the contact gap to the surrounding area of the circuit breaker unit for removing a switch gas from the contact gap. Several barriers that increase a flow resistance are arranged successively, spaced from one another, in the switch gas channel. At least one of the barriers is arranged between a first pipe section, which is surrounded by a second pipe section, and the second pipe section.