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US 4,097,912 AGranted
Electrical capacitor having an impregnated dielectric
AssigneeMcGraw-Edison Company
InventorsJohn Lapp, Fred S. Sadler
Life of this patent
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AssigneeMcGraw-Edison Company
InventorsJohn Lapp, Fred S. Sadler
Estimating the term…
An electrical capacitor having an improved dielectric system. The capacitor includes alternate layers of metal foil and polymeric dielectric film which is impregnated with a liquid dielectric composition composed of a mixture of mono-halogenated diphenyl oxide and a mono-halogenated alkyl diphenyl oxide where the alkyl group contains from 1 to 20 carbon atoms in the molecule. In processing the capacitor, the capacitor casing is vacuum dried at room temperature and the dielectric liquid is separately agitated under vacuum to remove gas from the liquid. The degassified liquid is introduced into the casing and the liquid is subjected to a vacuum while maintaining the capacitor at room temperature to impregnate the polymeric layers with the liquid. The capacitor has improved corona characteristics and low dielectric losses, and the liquid dielectric composition is substantially biodegradable.
An electrical capacitor, comprising a sealed casing, a capacitor pack in the casing and having a pair of electrically conductive strips and a pair of dielectric layers wound alternately to form the capacitor pack, and a dielectric liquid composition impregnating said dielectric layers, said dielectric composition comprising a mixture of a mono-halogenated diphenyl oxide and a mono-halogenated alkyl diphenyl oxide where the alkyl group contains from 1 to 20 carbon atoms in the molecule, and said dielectric layers being composed of polymeric film said capacitor having a high discharge inception voltage over its normal operating temperature range.
An electrical capacitor comprising a sealed casing, a capacitor pack in the casing and having a pair of electrically conductive strips and a pair of dielectric layers of polymeric film wound alternately to form the capacitor pack and a dielectric liquid composition impregnating said dielectric layers, said dielectric composition comprising a mixture of 5 to 95% by weight of a mono-halogenated alkyl diphenyl oxide where the alkyl group contains from 1 to 20 carbon atoms in the molecule and 95 to 5% by weight of mono-halogenated diphenyl oxide, said dielectric layers and said strips have contiguous surfaces, at least one of said contiguous surfaces having a plurality of surface irregularities to provide interupted contact between said contiguous surfaces, said capacitor having a discharge inception voltage greater than 1.5 kv/mil at all temperatures from -40.degree. to +90.degree. C.
An electrical capacitor, comprising a sealed casing, a capacitor pack in the casing and having a pair of electrically conductive strips and a pair of polymeric layers wound alternately to form the capacitor pack, and a dielectric liquid composition impregnating said dielectric layers, said dielectric layers composed of polypropylene and said dielectric compostion being a mixture of mono-chlorodiphenyl oxide and mono-chlorododecyldiphenyl oxide, said mixture having a pour point less than -20.degree. C, and said capacitor having a discharge inception voltage greater than 1.5 kv/mil at all temperatures from -40.degree. to +90.degree. C.
Dependencies are inferred from the claim text.