GB422411A - Improvements in or relating to electric valve converting arrangements - Google Patents

Abstract

422,411. Converting ; frequency changing. HAIGHTON, C. A. A., (known as Haightoni, A. A.), 24, Laan Copes van Cattenburch, The Hague. April 5, 1933, No. 10225. Convention date, April 19, 1932. [Class 38 (ii)] Comprises a frequency-changing arrangement in which each of the tapping points of a ring winding arranged in a rotating field or each phase of a polyphase transformer, having a larger number of phases on the secondary side than on the primary side, has connected to it the electrode of one valve in each of a number of rings of valves, the other electrodes of the valves of each ring being connected together and to a pole of the secondary network, a control device permitting one valve in each ring to operate at a given instant. The valves employed are of the type which conduct in either direction or each valve may consist of two valves connected inversely in parallel. Fig. 1 shows an arrangement for supplying a three-phase network K1, K2, K3, from a polyphase network P, Q, R. The ring winding C associated with the network P, Q, R is connected to the network K1, K2, K3 through rings of valves K1, K2, K3. These valves are controlled by means of a distributer T which may be a mechanical arrangement or a rotating arc magnetically controlled. The controlcircuits are arranged so that the valves in the three rings of valves connected to points in the ring winding 120‹ apart are rendered conductive simultaneously. As the distributer is rotated the network K1, K2, K3 is connected to successive points of the ring winding and the frequency of the supply to the network will be proportional to the difference of the speeds of rotation of the field associated with winding C and the distributer T. Instead of a ring winding arranged in a rotating field a polyphase transformer having its secondary phase windings connected in a ring may be used. In a further modification a transformer having a star connected secondary winding is used, the star point providing a neutral. Specifications 140,853, 150,824, 150,825, 178,190, and 184,259, [all in Class 38 (ii)], are referred to. The Specification as open to inspection under Sect. 91 comprises also an arrangement for feeding a single phase circuit in which two rings of valve are used. In a further modification in which a star-connected secondary winding is used, one of the rings of valves is omitted, the phase lead being connected to the star point of the secondary winding. The Specification also stated that these arrangements were reversible and would also operate as rectifiers or inverters. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specifications 218,675, [Class 38 (ii)], and 388,771.