| 摘要 |
<p>PROBLEM TO BE SOLVED: To make heating of an insulating oil unnecessary, and to prevent bubbles from being caught up by using as an applying oil an insulating oil having a kinematic viscosity lower than a high-viscosity insulating oil impregnated into oil-impregnated insulating paper to be wound round a joint. SOLUTION: Oil-impregnated insulating paper is produced by putting insulating paper in a hermetically sealed enclosure, vacuum-drying it, and impregnating a high-viscosity insulating oil in a heated state into the paper after that. On the occasion of winding oil-impregnated insulating paper, winding is performed while feeding an insulating oil having a kinematic viscosity lower than the high-viscosity insulating oil impregnated into this oil-impregnated insulating paper, having a kinematic viscosity of 30 centi-stokes or less at 25 deg.C if possible. Consequently, bubbles are hardly caught up by an oil-impregnated insulator. Besides, heating of the insulating oil becomes unnecessary, and the workability is enhanced, and danger of catching fire etc., is also removed.</p> |
