Abstract: Provided is an impregnated capacitor wherein at least part of the capacitor element comprises a metallized polypropylene base film impregnated with an insulating impregnating agent comprising a compound having three condensed or non-condensed aromatic rings, the ratio of the amount of the impregnating agent which penetrates between the base film layers to that of said agent which penetrates into the base film per unit thickness (.mu.) being at least 60.

Abstract: An electrical insulating oil which is suitable for use in impregnating electrical appliances such as capacitors, cables and transformers, especially those in which plastic materials are used partially or totally as dielectrics or insulating materials, and electrical appliances that are impregnated with the above electrical insulating oil. The electrical insulating oil of the invention contains at least one monoolefin and/or diolefin having three condensed or non-condensed aromatic rings.

Abstract: An improved electrical insulating oil which is stable in refining treatment and good electrical properties are maintained under high temperature conditions, and oil-filled electrical appliances impregnated therewith. The electrical insulating oil comprises 1,1,-diarylalkenes which are represented by the following general formula (I): ##STR1## wherein R.sub.1 to R.sub.4 's are the same or different and each of them is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and m and n are integers from 0 to 3, inclusive.

Abstract: An oil-filled capacitor which can be made small in size and has excellent electrical characteristics. The capacitor of the present invention is characterized in that it is made by impregnating a film-wound capacitor element with 1-phenyl-1-(benzylphenyl)ethane, at least a part of the dielectric material of said capacitor being made of a plastic film.

Abstract: An electrical insulating oil which can be produced easily at low cost, scarcely contains undesirable components of tarry substance, unsaturated compounds and carbonyl compounds, does neither swell nor dissolve plastic materials, and has excellent electrical properties. The electrical insulating oil is characterized in that it comprises a fraction having boiling points in the range of 270.degree. to 350.degree. C. which is prepared by distilling the heavier products obtained from the process for producing ethyltoluene by alkylating toluene with ethylene in the presence of synthetic zeolite catalyst. Included also in the present invention are oil-filled electrical appliances that are produced by impregnating them with the above insulating oil.

Abstract: A refined electrical insulating oil and oil-filled electrical appliances impregnated therewith. The electrical insulating oil is quite suitable for use in oil-filled electrical appliances in which insulating materials or dielectric materials made of plastics are employed. The electrical insulating oil is prepared by refining a mixture of unsaturated dimers of styrenes and alkylbiphenyls and/or alkylnaphthalenes, using a solid acidic substance.

Abstract: An improved electrical insulating oil and oil-filled electrical appliances impregnated therewith. The electrical insulating oil is quite suitable for use in oil-filled electrical appliances in which insulating materials or dielectric materials made of plastics are employed. The electrical insulating oil comprises (a) an electrical insulating oil except polyaromatic hydrocarbons and (b) an aromatic monoolefin and/or diolefin having two condensed or noncondensed aromatic nuclei.

Abstract: A novel electrical insulating oil and oil-filled electrical appliances that are impregnated with the novel insulating oil. The electrical insulating oil is quite suitable for use in oil-filled electrical appliances in which insulating materials or dielectric materials made of plastics are employed. The electrical insulating oil comprises (a) at least one member of alkylbiphenyls and alkylnaphthalenes and (b) at least one member of monoolefins and diolefins each having two condensed or noncondensed aromatic nuclei.

Abstract: An improved electrical insulating oil and oil-filled electrical appliances impregnated therewith. The electrical insulating oil is quite suitable for use in oil-filled electrical appliances in which insulating materials or dielectric materials made of plastics are employed. The electrical insulating oil comprises (a) at least one member of diarylalkanes and (b) at least one member selected from the group of mono- and/or diolefins having two condensed or noncondensed aromatic nuclei.