GB402218A - Improvements in apparatus for heating incandescent cathodes in gas discharge devices - Google Patents

Abstract

402,218. Discharge apparatus. JENAER GLASWERK SCHOTT & GEN., Otto-Schott- Strasse, Jena, Germany. Sept. 21, 1932, No. 26212. Convention date, Sept. 22, 1931. [Class 39 (i).] In circuits for incandescent-cathode, gasdischarge devices in which an additional transformer h has its primary h<1> in the discharge circuit g and its secondary h<2> in the cathodeheating circuit opposing the voltage of the transformer windings e to reduce the heating current as the discharge current rises and so to keep the total heating of the cathode constant, the iron core of the transformer h is saturated when the discharge device is operating at full load so that, on the occurrence of overloads, the heating current cannot increase through an increase of the secondary voltage of the transformer h above the voltage of the windings e. Fig. 1 shows a 3-phase rectifier circuit using three single-phase rectifiers a each with an anode b and an indirectly-heated cathode c. In a single-phase circuit supplying a glowdischarge tube having two indirectly-heated electrodes (Fig. 2, not shown) the primary of the additional transformer is in the primary circuit of the transformer supplying the discharge current and may act as a ballast, whilst the secondary of the additional transformer is in series with the primary of the heating-current transformer and opposes the applied voltage. The Specification as open to inspection under Sect. 91 comprises also an arrangement in which the heating circuits are fed from additional secondaries on the discharge-supplying transformer, a choke being connected in the primary circuit so that the heating voltage drops as the discharge current rises. This subject-matter does not appear in the Specification as accepted.