The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 21, 1992
Filed:
May. 08, 1991
Atsushi Sato, Tokyo, JP;
Shigenobu Kawakami, Chiba, JP;
Keiji Endo, Kanagawa, JP;
Hideyuki Dohi, Kanagawa, JP;
Nippon Petrochemicals Company, Limited, Tokyo, JP;
Abstract
An electrical insulating oil composition having good low temperature characteristics which comprises at least 4 members selected from the group consisting of (a) m-ethylbiphenyl, (b) p-ethylbiphenyl, (c) o-benzyltoluene, (d) m-benzyltoluene, (e) p-benzyltoluene, (f) 1,1-diphenylethane, and (g) 1,1-diphenylethylene; and is characterized in that the proportion of solid phase at a temperature of -40.degree. C. of the electrical insulating oil composition is not more than 45% by weight and the proportion of the total quantity of solid phase is calculated according to the following general equation of solid-liquid equilibrium: ##EQU1## wherein X.sub.i is the equilibrium mole fraction of a component i in the liquid phase of the composition, .DELTA.H.sub.i.sup.f is the heat of fusion (cal.mol.sup.-1), T.sub.i.sup.f is the melting point (K), T is the temperature (K), and R is the gas constant (cal.mol.sup.-1.K.sup.-1). Electrical capacitors prepared with these electrical insulating oil compositions provide excellent operation at temperatures as low as -40.degree. C., preferably as low as -50.degree. C.