JPS646531B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a capacitor in which an electrode made of double-sided metallized paper and a dielectric material made only of plastic film are laminated and wound, and the capacitor element is impregnated with insulating oil. This invention relates to an improvement in a capacitor impregnated with an electrical insulating oil containing an acid ester compound. Foil-type capacitors and other equipment filled with electrical insulating oil are required to be flame retardant, and in place of conventional flammable electrical insulating oil, electrical insulating oil containing a phosphate ester compound with excellent heat resistance is being used. Applications are underway. However, electrical insulating oil containing phosphate ester compounds hydrolyzes under the influence of the water contained in the electrical insulating oil, producing strongly acidic phosphoric acid, and this phosphoric acid is used in electrical equipment. Adversely affects various materials. The reaction in which phosphoric acid ester is hydrolyzed to produce phosphoric acid is accelerated as the water content increases and the temperature increases. Therefore, in order to put an electrical insulating oil containing a phosphate ester compound into practical use, it is necessary to reduce the amount of water present in the electrical insulating oil, and to reduce the amount of water present in electrical equipment, even if it is only a small amount. However, the two important points mentioned above are the need to be extremely careful to prevent abnormal temperature rises. However, the capacitor to which the present invention pertains has the advantage of impregnating an insulating oil into a capacitor element formed by laminating and winding electrodes made of double-sided metallized paper and a dielectric material made only of plastic film. , Due to the self-healing effect at weak points in the dielectric, a local temperature rise in the self-healing part cannot be avoided, and it is virtually impossible to completely remove moisture from the electrode paper and electrical insulating oil. Therefore, in the case of conventional aluminum, a deposited film of 250 Å or more, and in the case of zinc, a deposited film of 700 Å or more was constructed using double-sided metallized paper, which was deposited at a constant thickness regardless of the metallicon metal bonding area or the capacitance forming area. In capacitors, it has been impossible to apply electrical insulating oils containing phosphate ester compounds due to the local temperature rise during self-recovery. Therefore, the inventor of the present invention focused on the fact that if the thickness of the vapor deposition film in the capacitance forming part is made thinner, the energy during self-recovery becomes smaller and the local temperature rise also becomes smaller. We prototyped capacitors impregnated with electrical insulating oil containing a phosphate ester compound and investigated their characteristics.We found that the thickness of the deposited film in the capacitance forming part was 100 to 200 Å when aluminum was used, and 250 Å when zinc was used. It has been found that when the thickness is ~500 Å, even if a self-healing effect occurs, only a small amount of phosphoric acid is generated, and a capacitor with stable characteristics can be obtained without deteriorating the capacitor characteristics. In the present invention, the thickness of the vapor deposited film at the bonding portion with the metallicon metal is equal to or greater than the conventional vapor deposition thickness, which is constant regardless of the bonding portion of the metallicon and the capacitor forming portion, but in the case of an aluminum vapor deposited film, the thickness is 250 Å or more. In the case of a zinc evaporated film, the thickness should be 700 Å or more, and in the case of an aluminum evaporated film, the evaporated film thickness in the capacitor forming part should be 100 Å or more.
By setting the thickness to 200 Å, or 250 to 500 Å in the case of a zinc-deposited film, a capacitor having stable characteristics can be provided even when impregnated with electrical insulating oil containing a phosphate ester compound. Embodiments of the present invention will be described in detail below with reference to the drawings. The figure schematically shows a part of a cross-sectional view of a capacitor according to an embodiment of the present invention in a plane including the winding axis. 1 is a 5 μm thick polypropylene film (dielectric), 2 is a double-sided The electrode is made of metallized paper, 3 is a vapor deposited film at the bonding portion with the metallcon metal, 4 is the vapor deposited film at the capacitor forming portion, and 5 is the metallicon metal layer. Table 1 below shows 10 capacitor elements of the configuration shown in the figure, each using an aluminum evaporated film, with a constant 300 Å evaporation film thickness on the metallicon metal adhesion part, and with different evaporation film thicknesses on the capacitor forming part, each with a total capacitance of 20 μF. make,
An experiment in which 500 VAC was applied in an atmosphere of 85°C to a sample impregnated with electrical insulating oil containing 10 PPM of water, containing 49% diallylethane, 50% tricresyl phosphate, and a small amount of other additives. This shows the results.

[Table] The initial tanδ in the table is the average tanδ measured at 200VAC, 60Hz before voltage application, and the 1000 hour survival rate is
It shows the number of samples in which the 10A fuse did not blow out as a percentage, and the capacity reduction rate (△C/
C) shows the average capacitance loss for the capacitors that remained after 1000 hours of testing.
As can be seen from the table, the thickness of the deposited film in the capacitance forming area is
If it is less than 100 Å, the stability of the deposited film itself is unsuitable, and if it exceeds 200 Å, it may be destroyed due to the influence of phosphoric acid, and variations in △C/C will be noticeable, and stable characteristics may not be achieved. I can't get it. Therefore, the thickness of the evaporated film in the capacitor forming part is 100 to 200
It can be seen that Å is suitable. The following Table 2 shows capacitor elements with the configuration shown in the figure using an aluminum evaporation film, with a constant evaporation thickness of 150 Å on the capacitor forming part, and with different evaporation film thicknesses on the metallicon metal adhesion part, each having a thickness of 1μF. 49% diallylethane, 50% tricresyl phosphate, and a small amount of other additives.
This shows the results of a charge/discharge test using a sample impregnated with electrical insulating oil containing 10 PPM of water.

【table】

[Table] The capacitance was set to 1μF to make charge/discharge tests easier, and has no other meaning. The initial tanδ in the table is
This is the tanδ before the charge/discharge test measured at 200VAC, 60Hz, and the tanδ after the test is 200VAC, 60Hz after the charge/discharge test.
The capacity reduction rate after the test indicates the change in capacity before and after the charge/discharge test, and both are average values. As can be seen from the table, it can be seen that the characteristics of the deposited film thickness of the metallcon metal bonding part of 250 Å or more are stable. As a result of similar experiments regarding the zinc vapor deposited film, it was confirmed that good characteristics were obtained when the vapor deposited film thickness of the metallcon metal bonding part was 700 Å or more and the vapor deposited film thickness of the capacitor forming part was 250 to 500 Å. Ta. As described above, the capacitor of the present invention, in which the capacitance forming part and the metallic bonding part have different deposited film thicknesses, suppresses hydrolysis of the phosphate ester compound, and is a long-life, highly reliable capacitor.

[Brief explanation of the drawing]

The drawing is a schematic cross-sectional view of a capacitor according to an embodiment of the present invention in a plane including the winding axis. 1...Plastic film (dielectric), 2...
. . . Electrodes made of double-sided metallized paper, 3 . . . evaporated film at the adhesion portion with metallcon metal, 4 . . . evaporated film at the capacitance forming portion, 5 .

Claims (1)

[Scope of Claims] 1. A capacitor formed by laminating and winding a dielectric material made only of a plastic film and an electrode made of double-sided metallized paper, wherein the impregnating agent is an electrical insulating oil containing a phosphate ester compound, and the double-sided metal An oil-immersed plastic film capacitor characterized in that the electrodes of the chemical paper are made of aluminum, and the deposited film thickness at the adhesive part with the metallicon metal is 250 Å or more, and the deposited film thickness at the capacitance forming part is 100 to 200 Å. 2. In a capacitor formed by laminating and winding a dielectric material made only of plastic film and an electrode made of double-sided metalized paper, the impregnating agent is an electrical insulating oil containing a phosphate ester compound, and the electrode made of double-sided metalized paper is made of zinc. An oil-immersed plastic film capacitor characterized in that the thickness of the deposited film at the bonded portion to the metallcon metal is 700 Å or more, and the thickness of the deposited film at the capacitance forming portion is 250 to 500 Å.