Abstract: A vacuum circuit interrupter comprising an insulated, evacuated, cylindrical housing for a stationary electrode and a movable electrode, with an arc shield provided with a predetermined spacing from and connected to the stationary electrode. The dimensions of the electrodes are asymmetrical with the movable electrode being smaller.

Abstract: There is provided a novel vacuum detection means utilizing a high frequency, high voltage device to excite an electrical discharge in a vacuum whose characteristics are dependent on the level of the vacuum contained therein. This discharge current allows the degree of vacuum to be continuously monitored.

Abstract: A vacuum circuit interrupter including axial magnetic field generating means, and arc contact structure comprising means for spacially modulating the axial magnetic field over the area of the contact. This contact structure produces adjacent regions of different magnetic field strength over the contact area, whereby a plurality of spaced apart low arc voltage, stable parallel arc current paths are established over the contact area.

Abstract: An improved vacuum-type circuit interrupter has arc contacts which have integral axial magnetic field generating means as part of the arc contact. The axial field generating means comprises a plurality of partial coil turn portions which form an effective single turn coil disposed between a supporting plate and an arcing contact portion. The coil turns are electrically in series between the conductive support rod lead-in and the arcing contact perimeter portion. The supporting plate and a plurality of support pins, each of which are of high strength, low conductivity material support the partial coil turn portions and the arc contact without diverting substantial current from the coil turn portions. The axial magnetic field generating means may be structurally a part of both contacts or only one of the contacts.

Abstract: A vacuum arc current switching device employs a shielding arrangement including a plurality of coaxially disposed cylindrical non-conducting members for minimizing exposure of the interior wall surfaces of the enclosure to vapor deposition of cathode material so as to prevent the formation of secondary arc terminals on the interior surfaces of the enclosure. The shielding being non-conducting prevents secondary arc formation which would otherwise permit arcing from the cathode to the shield and then back to the anode. The shielding further comprises annular transverse members disposed at the ends of the enclosure so as to protect the end wall surfaces as well.

Abstract: A vacuum circuit interrupter contact being generally cup-shaped with a radially inward extending lip with slots formed through the lip and side wall for directing current flow and including a flat annular contact cap attached directly to the lip portion. The annular contact cap extends from the side walls radially inward to a position inside of the lip-shaped portion. At the inner diameter of the annular contact cap an arcing ring is formed which extends downward along the inner diameter of the lip portion. The annular contact cap can be formed from a material having good arc interrupting properties, such as chromium copper, while the rest of the contact can be formed from a material which is easy to fabricate and has good electrical conductivity properties, such as copper. In another embodiment of the invention, the lip portion and the annular contact cap are formed as one member but any slots formed in the lip-shaped portion do not extend to the contact making surface.