Extinguishing chamber of magnetic blow-out type for an electrical breaking device and electrical breaking device equipped with such a chamber

An extinguishing chamber of magnetic blow-out type for an electrical breaking device, said extinguishing chamber comprising a magnetic field source, a magnetic carcass and a breaking region in which an electric arc is liable to form notably when a breaking pole belonging to a breaking device is opened, said field source being arranged to generate a magnetic field configured to move said electric arc in order to stretch it and accelerate its cooling and its extinguishing, and said carcass being arranged to channel said magnetic field, said breaking pole comprising a fixed contact and a movable contact which moves with respect to said fixed contact between a closed position and an open position on a path defining a breaking plane, and said breaking region extending at least in said breaking plane, characterized in that said extinguishing chamber has a mostly symmetrical form with respect to a median plane which coincides with said breaking plane, in that said field source is arranged in the near vicinity of and opposite said breaking region and is oriented to generate magnetic field vectors which are essentially parallel to said breaking plane, in that said carcass surrounds said breaking region and said field source and comprises a window which is open toward the outside in order to allow a passage of said movable contact, and in that said carcass is stood up against said field source and closes in front thereof so as to create an air gap in the magnetic circuit formed by said field source and said carcass and to thus maximize the magnetic field that passes through said breaking region.