GB220608A - Improved arrangements for increasing the frequency of electric currents - Google Patents

Abstract

220,608. Touly, M. L. Aug. 18, 1923, [Convention date]. Generating c i r c u i t s employing vacuum or low-pressure apparatus; thermionic generators. - Single-phase or polyphase currents are converted into single-phase alternating or undulating currents of higher frequency by means of low-pressure gas or vapour apparatus in which ionization occurs, such apparatus being provided with grids which are charged by means of an alternating current which is displaced in phase with respect to the supply current. In the arrangement shown in Fig. 1, a single-phase generator 6 is connected to the anodes 4, 5 of a mercury-vapour lamp through an autotransformer 7, the cathode 1 being connected to the middle point of the auto-transformer through an oscillating circuit 8, 9 tuned to dcuble the frequency of the generator 6. The grids 2, 3 are connected across the condenser 11 of a circuit tuned to the frequency of the generator, the. inductance 12 of this circuit being coupled to the auto-transformer. The grid potentials are displaced 90‹ in phase from the corresponding anode potentials, and a series of impulses at twice the frequency of the generator is applied to the tuned circuit 8. 9, which may represent a wireless antenna, a high-frequency electric furnace, or the like. In another arrangement, Fig. 3, a single-phase current from the generator 20 is converted into twophase currents by a phase-converter 21, the twophase currents being applied to the anodes of mercury-vapour lamps 22, 23, which cause currents to pass alternately in opposite directions through the primary windings 25, 26 of a transformer 24. The grids of each lamp are connected to tappings on the phase supplying the other lamp, and single-phase current of double the frequency of the generator is obtained in the secondary winding 27 of the transformer. In another arrangement, three-phase current is transformed into six-phase current and alternate phases of the latter are connected to the anodes of a pair of lamps, the cathodes of which are connected to the neutral point through the primary windings of a transformer. A single-phase current of three times the frequency of the original three-phase current is obtained in the secondary winding. The grids are excited with currents of the desired phase by means of a phase transformer or inductance. In a modification, Fig. 9, a lamp 52 with six anodes connected to the terminals a - - f of the six-phase transformer 51 is employed, and rectified impulses are applied to a circuit 54, 55 tuned to six times the original frequency. The grids are excited through inductance coils 62 - - 67 connected to the proper phases, and are connected to the cathode through resistances 56 - - 61. The amplitude of the multiple-frequency currents mav be varied by changing the phases of the potentials applied to the grids.