GB806164A - Improvements in or relating to electromagnetic coils - Google Patents

Abstract

806,164. Transformers and inductors; magnetic compositions. 'SYLVANIA ELECTRIC PRODUCTS Inc. April 14, 1955 [April 15, 1954], No. 10747/56. Class 38 (2). An inductor or transformer comprises one or more coils 1 made by winding strips of copper or aluminium, enclosed in a coating 4 of ferromagnetic powder, e.g. powdered iron, embedded in a binder such as epoxy resin, nylon, polystyrene, wax, shellac, varnish, polyethylene, lacquer, glass or ceramic. The winding turns may be separated by a spiral strip 2 of insulation such as paper or resin, or by coating them with enamel, lacquer, resin, or oxide which may be produced by anodization. The coating 4 may be applied by dipping, spraying or painting and dried while rotating with their leads, soldered to the conductor ends, pushed into porous plastic mounted on a slowly turning shaft. Zinc oxide and mica may be added to the coating as fillers. With epoxy resin, a catalyst such as ethylene diamine, or diethylene triamine may be added. The coating may be separated from the coils by insulating discs or washers. The space about which the coils are wound may be filled by a non-magnetic or magnetic core 10, e.g. a screw plug. To form a transformer two coils may be wound side by side, Fig. 4, with one surrounding the other, or in a bifilar manner. The coating may extend between the coils. Interturn or intercoil capacity may be determined by the coating filler, the spacing, or the dielectric constant of the spacing material 13.