JPS6022455B2 - capacitor - Google Patents

Description

[Detailed description of the invention] The present invention is trimethylol.

This invention relates to a capacitor in which bread is impregnated with electrical insulating oil made of esters produced from fatty acids. Conventionally,
Mineral oil or polychlorinated biphenyls (hereinafter referred to as PCB) have been used as the stunning green oil for impregnating capacitors using capacitor vapor, plastic film, or a combination thereof as a dielectric.

In particular, PCBs were used in large quantities due to their nonflammability and excellent electrical properties, but their use was banned after their toxicity became apparent. Therefore, an excellent nonflammable electrical insulating oil that can replace PCBs has not yet been put into practical use, and flammable synthetic insulating oils are currently used as impregnating agents. The present invention applies to these PCs.
By using esters, such as trimethylolpropane tricaprylate, which have excellent properties such as electrical properties, thermal stability, and heat resistance, as electrical insulating oils in place of B and synthetic insulating oils. The aim is to improve the electrical characteristics of capacitors, make them smaller and lighter, and make them more fuel efficient.

From the above point of view, esters such as dioctyl phthalate (hereinafter referred to as DOP) and dioctyl adibate, which are used as general plasticizers, have been studied, but many problems still remain.

However, as shown in Table 1, the electrical insulating oil used in the capacitor of the present invention has excellent physical properties such as a lower pour point and a higher flash point than conventional wastes, and in particular has a high flash point. is approximately 1000 qo higher than that of mineral oil, which is approximately 130 qo, and synthetic insulating oil, which is approximately 140 qo, which is the key to greatly improving the combustion efficiency of capacitors. Furthermore, as shown in Table 2, the electrical properties such as n6 and volume resistivity are also excellent, and the properties of the capacitor can be greatly improved. Table 1'', n-day Table 2 Moreover, unlike PCB, the fly-stunned green oil used in the capacitor of the present invention is an aliphatic ester and a hydrocarbon compound that does not contain chlorine, so it is not biodegradable. It has a high level of bioaccumulation and has low bioaccumulation potential, providing high safety in the capacitor manufacturing process and waste oil disposal.

Examples will be described below. A polypropylene film is interposed between a pair of electrode foils and wound to form a capacitor element.

After this capacitor element is housed in a metal case, it is heated in a vacuum tank and vacuum-dried.
(referred to as CA) is injected under vacuum to thoroughly impregnate. After cooling to an appropriate temperature, the injection port is also sealed to form a condenser.
In addition, capacitors were fabricated using the same procedure as described above for capacitor elements formed by winding a metallized dielectric material on which electrode metal was vapor-deposited around a polypropylene film or polyethylene terephthalate film. After measuring the electrical characteristics of the capacitor created in this way, it was kept warm at 95qo and heated continuously for 1000
The heat resistance stability of the time-degradation was investigated.

The results are shown in FIGS. 1 to 6. Furthermore, the TA of the capacitor was manufactured by using polypropylene film as a dielectric material and mixing trimethylolpropane ester.
The n6 characteristics and corona characteristics are shown in FIGS. 7 and 8. As a result, with regard to tan6, the number of carbon atoms in the fatty acid becomes small, and as the dielectric constant of the trimethylolpropane ester increases, the tan6 of the electrical insulating oil increases, resulting in a large rise in the tan6 of the capacitor, especially at high temperatures. This is not desirable. On the other hand, regarding corona properties (corona onset voltage), a small number of carbon atoms in the fatty acid is effective because it increases the breakdown voltage of the trimethylol ester, but conversely, when the number of carbon atoms increases, the breakdown voltage decreases and the corona properties decrease. bring. This is due to solidification of the trimethylol-based ester at room temperature, which is not preferable. From the above, it has been found that a carbon number n of 4 to 12 is the range in which preferable results can be obtained.

Regardless of the dielectric material or electrode structure, T
Capacitor using electrical insulating oil made of MP-CA [
Curve b] shows stable characteristics with very little increase in tan6, proving that the capacitor according to the present invention is thermally stable.

Further, Table 3 shows that a polypropylene film is used as the dielectric material, and the conventional DOP and the T
This is a comparison of the volumes required to obtain the same capacitance value for capacitors impregnated with electrical insulating oil made of MP-CA, with a capacity ratio of 100 for the former and 75 for the latter, which is 25%.
4. Formed.

This is because the electrical insulating oil made of TMP-CA has a high corona initiation voltage and can store a large amount of energy per unit volume, making it possible to reduce the capacitor volume. Although Table 3 and above describe examples of electrical insulating oils made of TMP-CA, electrical insulating oils using fatty acids with carbon number n of 4 to 12 other than caprylic acid also have TMP as shown in Table 1. - Shows almost the same physical and chemical properties as CA.

Note that as the number of carbon atoms in the fatty acid increases, the pour point approaches room temperature and the viscosity also increases, but it remains within the range that can be used by high-temperature impregnation. All capacitors impregnated with electrical insulating oils made of these esters showed excellent electrical properties and thermal stability. It goes without saying that capacitors with excellent performance can also be obtained using electrical insulating oils that are appropriately mixed with these esters. Normally, the structure of a capacitor element is to construct a capacitor by inserting similar materials such as capacitor paper and plastic film between the electrodes as a current carrier, but capacitors are made by roughly combining different materials such as capacitor vapor and plastic film. A multilayer capacitor constructed by laminating electrodes and a dielectric material can also produce the old-fashioned effects of electricity as described above.

Therefore, since the capacitor according to the present invention is small and its performance is stable over a long period of time, it is possible to provide a highly reliable capacitor, and it is very useful industrially.

[Brief explanation of the drawing]

Figures 1 to 6 show conventional dioctyl phthalate (DOP) and an ester of trimethylolpropane and caprylic acid (TMP-C), which is an embodiment of the present invention, as electrical insulating oils.
Figure 1 shows capacitor vapor, Figure 2 shows polypropylene film, Figure 3 shows polyethylene terphthalate film, 4
The figure shows a metalized polypropylene film, Figure 5 shows a metalized polyethylene terephthalate film, and Figure 6 shows a metalized polypropylene film.
The figures show cases in which metallized vapor is used, and Figures 7 and 8 are characteristic diagrams of a capacitor of the present invention in which a polypropylene film is used as a dielectric material and is impregnated with ToIJ methylol-based ester. The tan8 characteristic diagram and FIG. 8 show the corona characteristic diagram. Book, Figure 2, Figure 2, Figure 3, Figure 4 *; Figure 5, Figure 7, Brother 8

Claims (1)

[Claims] 1. A capacitor element composed of an electrode and a dielectric material is produced from trimethylolpropane and a fatty acid having a carbon number n of 4 to 12 ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, R: - A capacitor characterized by being impregnated with an ester having the structural formula (CH_2)n-1CH_3) as electrical insulating oil.