GB911546A - Thermal electric alternator - Google Patents

Abstract

911,546. Inverting; automatic voltage control systems. DURANT, L. A. March 31, 1959, No. 10911/59. Classes 38 (2) and 38 (4). [Also in Groups XXXVI and XL (a)] Apparatus for converting thermal energy into A.C. electrical energy comprises a pair of electrically common emissive electrodes 1, a pair of independent control electrodes 3 and a pair of independent collector electrodes 2, the arrangement being such that a substantially equal difference of potential is produced across each pair of emissive and collector electrodes when the former are heated. The apparatus further includes a step-up transformer, having a secondary winding 15 connected to an electric load 13 and a primary winding 14 having its outer terminals connected to the collector electrodes and a mid-tap connected to both emissive electrodes. There is also provided an exciter inductance 19 having a mid-tap connected to the emissive electrodes, and outer terminals connected to the control electrodes through rectifiers 20, whereby a negative potential is alternately applied to each of the control electrodes with respect to the emissive electrodes when oscillating means 21, for inductively coupling alternating current to inductance 19, is energized, so that alternate electric pulses are produced in. the windings of the transformer when the emissive elements are heated. After applying a starting potential to the oscillating means 21, the apparatus may be self-excited by connecting a tertiary winding in the step-up transformer to the oscillating means. The apparatus may also include an electronic differential amplifier and voltage reference unit connected to the secondary winding 15 of the transformer through a third rectifier means and in series with the mid-tap connection of the inductance 19, and adapted to respond to a rectified sample of the A.C. output voltage and provide a bias potential in the mid-tap connection in proportion to the potential across the load and regulate the negative potential applied to the control electrodes so as to stabilize the alternating energy in the load 13 when the latter or the heating of the emissive electrodes is varied.