GB662112A - Improvements in or relating to vapour-electric discharge devices - Google Patents

Abstract

662,112. Discharge apparatus. WESTING- HOUSE ELECTRIC INTERNATIONAL CO. July 13, 1949 [Aug. 19, 1948], No. 18495/49. Class 39 (i). A vapour-discharge device comprises a starting electrode for producing the cathode spot on the liquid cathode, a keep-alive electrode to which is connected a source of unidirectional current to maintain the cathode spot, and a conductor which extends through the cathode and is arranged to carry current in a direction opposite to that in the keep-alive and whereby the cathode spot is anchored near the conductor. A metal container 1 carries a mercury, gallium, caesium, potassium or sodium cathode 2, a starting electrode 10, and a keepalive electrode 12 mounted on a conductor 13 which passes through insulators 14. A fullwave rectifier 21, fed from the transformer 20 is connected to the conductor 13 and impedances 18 in the return leads 16, 17 of the keep-alive circuit and the circuit of the conductor 13 are adjusted whereby the keep-alive arc will maintain one cathode spot and the total current, e.g. 30 amperes, in the conductor 13 is sufficient to anchor the cathode spot. The keep-alive arc current operates relay 25 to disconnect the starting transformer 11. The current in conductor 13 for fixing the cathode spot may be independent of the keepalive current.