GB966480A - Method of manufacturing tubular electrical capacitors - Google Patents

Abstract

966,480. Capacitors. SIEMENS & HALSKE A.G. April 18, 1963 [April 19, 1962], No. 15755/63. Heading H1M. A method of manufacturing a tubular electrical capacitor of the rolled composite dielectric and metallic strip type, includes the steps of interposing a reinforcing carrier strip between the last few turns of the composite strips and adjusting the final rating of the capacitor by removing an end portion of the composite strips and supporting carrier strip. The drawing shows a tubular capacity provided with metallic end-contact coatings 2 across the axial ends. A reinforcing carrier strip 7 is coiled together with the last turns of two thin composite strips formed by dielectric films 3 and 5 carrying metal films 4 and 6, and enables the required number of turns to be removed whilst the capacity is being measured. The strip 7 may be of stretched polystyrene, polyethylene-terephthalate, polycarbonate or polyethylene. The capacitors may alternatively be of the type formed by winding four strips each comprising two dielectric films and an intermediate metallic film, the strips being so arranged that part of the dielectric is in a field-free space while part is dielectrically active. The part in the field-free space may be cellulose acetate and the dielectrically active part may be polystyrene. The metal may be vaporized on to one dielectric layer and the other dielectric layer may be coated on to the metal. The carrier strip 7 may be located in a field-free space. To avoid changes in capacity after the capacity has been adjusted the wound capacitor should be heated before subjection to the Schoop process of applying the end contact coatings.