# US 5,708,558 A · Capacitor having dielectric material containing calcium oxide

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- Number: US 5,708,558 A
- Document ID: US5708558A
- Status: Granted
- Kind: A
- Application number: 08/650,760
- Filed: 1996-05-20
- Granted: 1998-01-13
- Earliest claimed: 1996-05-20
- Assignees: Commonwealth Sprague Capacitor Inc.
- Inventors: Andrew E. Dequasie
- Web page: https://patentgrep.com/patent/US5708558A

## CPC

- H01G 4/221: {characterised by the composition of the impregnant}
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)

## Abstract

A metalized film capacitor has a plurality of electrodes separated by dielectric spacers and contains a dielectric fill system including 1 to 50 wt % of calcium oxide scavenger. This dielectric fill system is especially useful in aluminum metalized film capacitors for AC service.

## Claims

### Claim 1

A film capacitor comprising wound dielectric films having metalized surfaces, said wound films enclosed in a case, said case containing dielectric material surrounding said wound films, said material containing 1 to 50 weight percent of calcium oxide.

### Claim 2 (depends on 1)

The film capacitor of claim 1 wherein said films are polypropylene film, said metalized surfaces are selected from the group consisting of aluminum, aluminum alloy, and zinc.

### Claim 3 (depends on 2)

The film capacitor of claim 2 wherein said dielectric material is selected from the group consisting of phthalate ester, canola oil, rapeseed oil, and epoxidized linseed oil; and said calcium oxide is present from 10 to 20 weight percent.

### Claim 4 (depends on 3)

The film capacitor of claim 3 wherein said dielectric material contains a potting compound including prepolymers and crosslinkers.

### Claim 5 (depends on 4)

The film capacitor of claim 4 wherein said prepolymer is selected from the group consisting of dehydrated castor oil, butadiene prepolymers, and hydroxy-terminated butadiene prepolymers; and said crosslinker is selected from the group consisting of hexane diol diacrylate, and trimethylol propane triacrylate.