GB205948A - Improvements in or relating to electric transformers - Google Patents

Abstract

205,948. Scanes, A. E. L., and Metropolita:n-Vickers Electrical Co., Ltd. Sept. 4, 1922. Transformers.-An intervalve transformer, of the kind in which the inductance of the primary and secondary windings can be varied simultaneously without varying the coupling between them, comprises primary and secondary windings each divided into two parts and wound in two coaxial coils, the larger coil 2 of the primary being wound on the same bobbin as, but spaced apart from, the larger coil 4 of the secondary, while the smaller coils 1, 3 of each winding are similarly mounted on another bobbin, one or other of the bobbins being rotatable about an axis perpendicular to the axes of the coils for the purpose of simultaneously varying the inductance of the primary and secondary circuits. As shown in Fig. 4, the coils 2, 4 are wound in grooves 20, 21 on a fixed bobbin 12, the coils 1, 3 being wound in grooves 18, 19 on a bobbin 13 rotatably mounted inside the bobbin 12 on spindles 16, 17. The inner and outer coils are connected by flexible connections 25, 28, 36, 39 in the form of flat spiral springs, and by conductors passing through axial holes and along peripheral grooves in the spindles.