Paper Title
Nanocapillaries in Insulating Oil Impregnated Electrotechnical Pressboard

Paper presents measurement bench for oil absorption speed during the impregnation of electrotechnical pressboard or other porous materials. The station allows for record of a measuring cylinder images, filled with insulating oil with the pressboard sample placed there in, and thus precisely record the volume of the absorbed oil and the time it was absorbed. It was foundthat the time to complete the pressboardimpregnationprocess was approximately 2∙106 s. During this time, pressboard absorbs insulating oil in a volume of about 25.6% of the pressboard volume. This means that the free space occupies in pressboardabout 25.6% of its volume. Research of press board free surfaces howedthatit was about 10 m2 per cm3 of pressboardvolume. On the basis of this data, it was determinedthat the meancapillarydiameter of pressboard was about 25.6 nm. Keywords - Electrotechnicalpressboard, insulatingoil, freesurface, capillary.