GB1116161A - Improvements relating to electrical coils - Google Patents

Abstract

1,116,161. Transformers, inductances. SPERRY RAND Ltd. 21 Oct., 1965 [21 Oct., 1964], No. 42911/64. Heading H1T. A coil assembly comprises two or more superimposed layers each comprising a resin impregnated glass fibre base 11 having printed thereon a conductive spiral 12, Fig. 1, or 13, Fig. 2, and contact rings 14, 15, 16, 17 as shown, the adjacent spirals being mutually insulated by resin coating and/or by interleaved sheets. An inductor is formed by superimposing the Fig. 2 layer on the Fig. 1 layer, such that contacts 15a, 17a are directly above contacts 14a, 16a, drilling a hole through contacts 15a, 14a and through 17a, 16a, and plating the inner surfaces of the holes with conducting material by an electroless process to connect spirals 12, 13 in series. Several such pairs of interconnected layers may be superimposed, each succeeding pair being relatively angularly displaced clockwise by one contact spacing, a hole is drilled to pass through contacts 16b, 17b of the first and second lower layers and 16a, 17a of the third and fourth upper layers to connect the pairs in series. To provide a transformer, which may be an autotransformer, Fig. 2, layer is superimposed on Fig. 1 layer but relatively angularly displaced clockwise by one contact spacing, and several such pairs of layers are superimposed, and holes are drilled through contacts 14a, 16a and 15a, 17b to connect alternate spirals in parallel to produce separate primary and secondary windings.