Abstract: A guide sleeve for the movable contact rod of a vacuum-type circuit interrupter fits within the usual tubular bellows of the interrupter. The bellows has some of its annular convolutions located axially-inwardly of the axially-inner end of the guide sleeve. A coating of self-lubricating plastic material is provided on the outer peripheral surface of the guide sleeve and on its inner end surface. This coating is sufficiently close to the internal surface of the bellows as to be contacted by said convolutions when the contact rod is axially moved during operation of the interrupter. The lubricating properties of the coating reduce friction between said convolutions and said coated sleeve.

Abstract: This vacuum-type circuit interrupter comprises a plate located at the outer side of one end cap of the evacuated envelope of the interrupter. Within the envelope there are separable beryllium contacts, one of which is carried by a movable contact rod extending through aligned apertures in the end cap and the plate. A flexible metal bellows extends freely through the aperture in the end cap and is joined at its outer end to the plate and at its inner end to the contact rod. A cup-shaped metal shield for the bellows comprises a tubular body portion surrounding the bellows and having a free-end region located within the aperture in the end cap during at least the final portion of an opening stroke of the movable contact rod. A metal shield within the envelope surrounds said tubular body portion in spaced relation and renders the region around said tubular body portion a region of very low electric stress.

Abstract: A vacuum interrupter having a current interrupting rating exceeding 20,000 amperes r.m.s. comprises an evacuated envelope and first and second disc-shaped contacts within the envelope. The envelope comprises a metal housing having a generally cylindrical portion surrounding said contacts and electrically connected to said first contact. The space between said cylindrical portion and said second contact is so small that during the interruption of currents above 20,000 amperes r.m.s., 25% or more of the arcing current frequently will flow between said housing and said second contact and bypass said first contact. Arc-revolving means associated with the second contact causes any arc between the outer periphery of the second contact and the cylindrical housing portion to revolve about the second contact.An electric bus located near the envelope is normally electrically connected to said first contact to carry current that flows between the contacts.