| 摘要 |
1,191,299. Capacitors. SIEMENS A.G. 22 Dec., 1967 [23 Dec., 1966], No. 58368/67. Heading H1M. The dielectric in an impregnated wound capacitor comprises foils of plastics material which is swollen by the impregnant. The swelling of the dielectric fills up gaps which would otherwise be filled with the impregnant and have lower breakdown resistance. The tightness of the capacitor roll may be controlled so that swelling does not interfere with impregnation. Alternatively impregnation may be carried out at a low temperature when the rate of swelling is low, and the temperature then raised to accelerate swelling. The dielectric material may be polypropylene; the impregnant insulating oil containing 15 to 20% aromatic constituents, 30% naphthenes and 50 to 60% paraffins. The electrodes may compries foils of insulating material such as paper metalized on both sides, the insulating material accordingly lying in the field-free space of the capacitor. |
