GB342263A - Improvements in and relating to the control of unilateral electric current consuming devices - Google Patents

Abstract

342,263. Vapour &c. lamp systems. BRITISH THOMSON - HOUSTON CO., Ltd., Crown House, Aldwych, London.- (Assignees of Wantz, J. B. ; 324, North Harvey Avenue, Oak Park, Illinois, U.S.A.) Oct. 17, 1929, No. 31588. Convention date, Oct. 22, 1928. [Class 38 (iv).] In supplying from an alternating current circuit a consuming device, such as an X-ray tube, utilizing only half the e.m.f. wave a device is provided for absorbingenergy from the unused half of the wave so that the amplitude of that half of the e.m.f. wave may be made equal to or less than that of the useful halfwave, and the insulation requirements of the consuming device and its circuits are therefore reduced. The power factor is also improved. A transformer 73 furnishing high tension current from a secondary winding 74 to the anode circuit of an X-ray tube 67 has a further secondary winding 75 supplying a circuit comprising resistance or inductance and containing a synchronously-driven commutator 119, a two electrode valve or the equivalent. The cathode of the tube may be heated by a transformer 70 regulated by resistance 108 in its primary circuit and the primary of the transformer 73 may be supplied from a variable autotransformer 78 through a starting resistance 91. The resistance in the energy absorbing circuit may be in two portions 93, 100 each variable in conformity with the variations of anode volts and cathode current respectively so as to maintain the desired control of the unused portion of the voltage applied to the tube. Thus switches 82, 103 simultaneously control the tube and absorption circuits.