GB225583A - Improvements in loading coils for telephone lines - Google Patents

Abstract

225,583. International General Electric Co., Inc., (Assignees of Allgemeine Elektricitõts-Ges.). Dec. 1, 1923, [Convention date]. Void [Published under Sect. 91 of the Act]. Inductances.-A coil system for the simultaneous loading of trunk and quadruplex telephone lines comprises two windings wound respectively on the two halves of a ring-shaped core provided with a diametral magnetic bridge. The stray field arising on parallel connection of the windings is thereby confined to the interior of the coil. The core may be formed by juxtaposition of two D- shaped parts which may then be surrounded by a ring or cylinder. Alternatively the core may be in one piece or may be formed of a number of superposed annular discs each provided with a bridge-piece. To lower the reluctance of the bridge its axial length may be greater than that of the ring, the adjacent parts of the ring being correspondingly extended as shown in Fig. 6. The bridge may be of a material having greater permeability than that of the ring. The ring and bridge may be wire or of compressed pulverized material. A number of loading coils may be arranged in a box with the bridge set so as to prevent mutual influence; coils lying over one another should have their bridges at right angles. The coils may be surrounded by a light cylindrical or like shield of subdivided magnetic material. Two auxiliary windings each connected with one-half of the ring winding may be placed on the bridge.