High fire point dielectric insulating fluid having a flat molecular weight distribution curve

The method of producing a blend of oil intended for use in an oil filled electrical apparatus, the blend of oil having a substantially equal molecular weight density within predetermined molecular weight limits, said method comprising the steps of establishing a pseudo-rectangular molecular weight distribution curve having molecular weight limits of 500-700, determining the molecular weight distribution curves for equal quantities of a number of candidate synthetic and natural hydrocarbon oils, selecting from the distribution curves for the candidate oils a first curve that fills a portion of the established pseudo-rectangular distribution curve, selecting from the remaining distribution curves for the candidate oils those curves which when combined with the selected first curve and with each other fills the remaining portion of the pseudo-rectangular curve, normalizing the selected distribution curves to the predetermined quantity and blending the selected hydrocarbon oils represented by the selected distribution curves to form the liquid blend.

A liquid blend intended for use in an oil-filled electrical apparatus to minimize the detrimental effects that can occur during high fault conditions which oil composition is a biodegradable and environmentally safe oil and consists essentially of a blend of oils including a natural saturated hydrocarbon oil and a synthetic saturated aliphatic hydrocarbon oil, said blend having a substantially equal molecular weight density in the range molecular weight range of about 500 to about 700, a fire point above 200.degree. C. and a pour point near 0.degree. C.

A liquid blend intended for use in an oil-filled electrical apparatus to minimize the detrimental effects that can occur during high fault conditions which fluid consists essentially of a blend of oils including one natural saturated hydrocarbon oil and two synthetic saturated aliphatic hydrocarbon oils, said oils being selected to provide a substantially equal molecular weight density in the molecular weight range of 500 to 700.

A liquid blend intended for use in an oil-filled apparatus, said fluid consisting essentially of a natural hydrocarbon oil of different molecular weight groups having different molecular weight distributions, said groups being selected to provide a substantially flat molecular weight distribution curve having a predetermined molecular weight range from 500 to 700 whereby a pseudo-rectangular shaped molecular weight curve is produced.