Patent GB-503592-A (GB)
Title: Improvements in electric valve converting apparatus
IPC: H02M1/00
Filed: 1937-07-08
Abstract: 503,592. on verting. BRITISH THOMSON-HOUSTON CO., Ltd. July 8, 1937, No. 19021. Convention date, July 8, 1936. [Class 38 (ii)] A converting arrangement for interconnecting a constant voltage A.C. or D.C. circuit and a constant current direct current circuit comprises] a magnetic core having two groups of windings arranged on its limbs, the groups being connected respectively through grid controlled discharge devices to the supply and load circuits, condensers being connected across the windings associated with the constant voltage circuit. In an arrangement for interconnecting a constant voltage circuit 10, 11, Fig. 1, and a constant current circuit 11, 12 a core 13 is provided having two limbs, on which windings 14, 15 and 16, 17 are mounted, the windings 14, 16 being connected through valves 20, 21 across the circuit 10, 11, and the windings 15, 17 through valves 22, 23 across the circuit 11, 12. Con- ' densers 18, 19 are connected in parallel with the windings 14, 16. The grid circuits of the valves are supplied from a source of A.C. of adjustable frequency and a phase shifting circuit 33, 34, 35 is provided in the grid circuit of the valves 20, 21 to advance the phase of the grid potentials. The amount of power transmitted can be varied by adjustment of the phase advance of the grid potentials applied to the valves 20, 21 or by an adjustment of the frequency of the source 26. Smoothing reactors 24, 25 are included in the two circuits connected. The arrangement shown operates to supply power from the circuit 10, 11 to the circuit 11, 12, but may be operated in the reverse direction if the polarity of the circuit 11, 12 is changed. Fig. 7 shows a modification in which a 3-phase A.C. control 148 is used. A threelimbed core is used having windings 133-138 arranged in pairs on the limbs. In a modification of this three single phase transformers having cores provided with air-gaps are used. In a further modification the windings are connected in zigzag. In this arrangement single phase cores may be used, further windings being provided on the cores and connected in series in a loop to act as equalizing windings. In the arrangement shown in Fig. 2 the circuit connections are arranged so that a single multianode discharge device 56 may be used. Alternatively two discharge devices, one connected to the windings 44, 46, 48, and the other to the windings 45, 47, 49 may be used. Fig. 9 shows an arrangement for inter-connecting a constant potential A.C. circuit 154 and a constant current direct current circuit 131. The windings 133, 135 and 137 are connected across the phases of a star-connected secondary winding 156 through a discharge device 157, while the windings 134, 136, 138 are connected to the D.C. circuit through a discharge device 158. The Specification as open to inspection under Sect. 91 comprised also the arrangements shown in Fig. 10 (Cancelled) in which a D.C. network 210 and an A.C. network 211 'are interconnected by means of valves 217-220 arranged in bridge connection, the A.C. circuit being connected to the centre-taps of windings 213, 214 arranged on a magnetic core 212. This subject-matter does not appear in the Specification as accepted.