VACUUM ARC-QUENCHING CHAMBER WITH NORMALLY-OPEN ELECTRIC CONTACTS

The invention relates to a vacuum arc-quenching chamber with normally-open electric contacts used in the construction of the electric switching equipments, in particular electromagnetic commutators. According to the invention, the vacuum arc-quenching chamber comprises a vacuum enclosure consisting of an upper cover () and a lower cover () between which there are interposed by brazing, by means of an alloy (), a fixed support (), an intermediary ring () and an annular ceramic insulator () protected at the inside against the deposition of metal vapour resulting in the switching process by a fixed screen () brazed on the fixed support () and inside which there is located a pair of electric switching contacts, a fixed contact () brazed on the fixed support () and a mobile contact () brazed on a mobile support (), maintained in the open position, at a distance d" from an arrester ring (), due to the precompression of an elastic bellows () and the atmospheric pressure pressing on its lower surface, the said bellows () being brazed to the lower side to a lower cover () and to the upper side to a mobile screen () and the mobile support () which is guided through the centre of the fixed torus-shaped contact () by means of a sleeve ().