GB259015A - Improvements in or relating to electrical transformers suitable for use with thermionic valve systems - Google Patents

Abstract

259,015. Graham, E. A., and Paddle, L. H. April 9, 1925. Transformers. - In iron-cored electric transformers for use in wireless apparatus employing thermionic valves, the primary and secondary windings 8, 2 are wound on detachable concentric spools 7, 1 of insulating material to enable a damaged winding to be replaced or to enable the transformation ratio to be varied by replacing an existing winding by one having a different number of turns. The spools may be formed with integral spacing flanges 4 for dividing the windings into sections, or each spool may be built up of a number of separate sections such as 4<a>, 4<b>, 4<c>, Fig. 3, or 10, Fig. 6 on which separate sections of the windings are wound. The spools are provided with shoulders against which the end flanges 3<a>, Fig. 3. and 6<a>. Fig. 6, abut, and the outer spool is provided with an inwardly extending flange 3<b> against which the inner spool abuts. The inner spool is provided with a hole of square cross-section through which the centre limb of the core extends. and an insulating bush may be provided. The core comprises complementary sets of E-shaped laminations formed with ends cut as shown in Fig. 7 adjacent layers of stampings being reversed so as to break joint. The laminations are clamped together between end plates or between a pair of channel-shaped members 11, Fig. 1, by bolts 9*, and a non-magnetic casing 12 which may be corrugated and carries insulated terminals 13 is provided.