GB182750A - Improvements in or relating to rontgen-ray installations - Google Patents

Abstract

182,750. Naamlooze Vennootschap Philips' Gloeilampenfabrieken. July 4,1921, [Convention date]. R÷ntgen-ray and like apparatus.-An auxiliary electrode. F, Fig. 1, is provided between the cathode K and the anti-cathode A, and is maintained during adjustable time intervals at such a potential that current can pass through the tube only during those intervals, for instance so long as the potential between the cathode and anti-cathode exceeds a determined minimum. The auxiliary electrode may be maintained for definite intervals at a negative, positive, or zero potential with respect to the cathode. Continuous or alternating current is supplied to the auxiliary electrode F through a commutator C, mounted on the shaft of a rectifying interrupter- 0, and having cross-connected segments engaging with two brushes a', a<2>, connected with the source of supply, a brush b<1>, connected with the auxiliary electrode, and a brush b<2> connected with the cathode. The brushes a<1>, a<2> are fixed on a rocker, and the brushes b<1>, b<2> are adjustable thereon, so as to vary the time-intervals, and the four brushes are adjustable together with respect to the commutator. As shown in Fig. 2, a positive potential II is supplied to the auxiliary electrode during the intervals 1, 2 and 4, 5, when the potential I applied between the cathode and anti-cathode exceeds a minimum m, and a negative potential during the other intervals 2, 4 and 5, 7, or the potential may be zero during the periods 1, 2 and 4, 5. By this means sparkless rectification by the interrupter O can be obtained. In another arrangement, the potential is zero during the periods 1, 2 and 4, 5, and positive during the other intervals, when current is diverted to the auxiliary electrode instead of being stopped. Specification 9690/15 [Class 39 (i), Electric lamps, Arc &c.], is referred to.