JPS58153301A - Method of producing nonlinear resistor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a non-linear resistor used in an overvoltage protection device K in an electrical system.

[Technical background and problems of the invention]

In electrical systems, overvoltage protection devices such as surge absorbers and lightning arresters are used to remove overvoltages superimposed on normal voltages and maintain the electrical systems and electrical equipment.

This overvoltage protection device uses a non-linear resistor that exhibits almost insulating properties at normal voltage and has a relatively low resistance value when overvoltage is applied.

The non-linear resistor is made by pressing and molding a material made of silicon carbide (810) or Fi zinc oxide (ZnO) mixed with a metal oxide, and firing.

ZnO-based non-linear resistors have steep non-linear characteristics in the small current range and have a sharp rise up to the large current range, so overvoltage protection devices using 8W-based non-linear resistors are recommended. You can make a better overvoltage protection device than this.

However, in the conventional ZnO-based nonlinear resistor, the leakage current increases greatly with respect to the constant Im voltage, and the magnetic pressure drops due to the impact current. Therefore, overvoltage protection 1 which is subject to lightning pulses and voltage nagepathies for a long period of time! However, there was a demand for a non-linear resistor having stable electric jL characteristics over a long period of time, ie, long life characteristics.

(Objective of the Invention) In view of the above needs, it is an object of the present invention to provide a method for manufacturing a non-linear resistor O having stable electrical characteristics over a long period of time, that is, having short life characteristics.

(Summary of Invention O) In order to achieve the above object, the present invention provides a method for manufacturing a nonlinear resistor in which a metal oxide containing zinc oxide as a main component is mixed and molded, and then fired. It is characterized by performing DWk@Aging/G for a certain period of time (-o). Under the condition that the leakage current of the initial nonlinear resistance element increases and then decreases under the condition that the aging for a certain period of time is It is desirable to carry out the process until the increased leakage current decreases to almost the same value as the initial leakage current value.

[Embodiments of the invention]

Hereinafter, the SJL of the present invention will be explained based on an example of AM.

The main ingredient is ZnO (ZnO) powder, which is the main ingredient.
(B It Oj * llization77 f'&
7 (Sb*Oj, oxidation/pm(□r,o,),
*Cobalt oxide (OoO) and manganese oxide (MnO)
Add powders such as 0.01 to 6.0 mol, respectively, and mix in a bowl. At this time, the oxide and an organic binder, such as Polypinish 7 Cicore, are mixed simultaneously.

The mixture thus obtained is placed in a dry granulation device, for example a spray dryer, to form spherical agglomerates. Apply this powder mixture to a t-press to a thickness of, for example, 100 cm in diameter and 2 cm in thickness.
Form into a 5m disc. Then 1000-1400'
After the surface of the obtained sintered body is polished, an aluminum electrode is thermally sprayed to form a non-linear resistor. For example, if the nonlinear resistor formed in this way is exposed to ambient temperature [
7ooo, 1lIIE rate (applied voltage peak value and Paris-1
4E Pressure Vxmn O ratio) 75% Te, fixed time 1
llIlc, apply temperature and voltage stress, ll1l
c. Perform aging. The time to apply IIR and voltage stress (II voltage waiting time is determined by observing the change in leakage current of the nonlinear resistor. Figure s1 shows the leakage current #t of the nonlinear resistor in the above example. The time to apply temperature and voltage stress (II) is the time B (approximately 24 hours) until the leakage current, which has increased once, decreases and becomes almost the same value as the initial leakage current. ) is desirable.

The conditions for applying stress and voltage stress, i.e.
The ambient temperature and charge rate may vary depending on the composition and formation method of the nonlinear resistor (9), and the pattern of change in leakage current as shown in Figure 1 (i.e., the initial leakage current increases and then decreases after completion). Therefore, the conditions of ambient temperature and charging rate are not limited to the above-mentioned examples. It goes without saying that it will not be implemented in a specific example.・$112!l!!ffd, This shows the life characteristics of the present invention and the conventional non-linear resistor, and the ambient temperature is 100'0. Charge rate is 85. 2 shows the change in leakage current of the non-linear resistor when - is applied. The solid line 0 shows the characteristics of the conventional non-linear resistor, and the dashed line shows the characteristics of the non-linear II antibody according to the present invention.

As is clear from the FLLZ diagram, the non-linear resistor of the present invention, that is, the aged non-linear resistor, has significantly improved life characteristics compared to the conventional non-linear resistor. In this way, the non-linear resistor of the present invention satisfies the characteristics required of a non-linear resistor for a gapless lightning arrester.

The apparatus used in the manufacturing method of the present invention is not limited to the upright embodiment, and it goes without saying that various types of apparatus can be applied as long as they can be used in the manufacturing method of the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to provide a nonlinear resistor with stable electrical characteristics over a long period of time, that is, excellent life characteristics.

[Brief explanation of the drawing]

Figures 1111 and 812 are characteristic diagrams showing the degree of change in leakage current versus am time of a nonlinear resistor according to an embodiment of the present invention. Figure 1 Figure 2 θ lθθ 2oθ t14 /'a7 LH)

Claims (1)

[Claims] 1. A method for manufacturing a non-linear resistor in which a gold-114 oxide containing zinc oxide as a main component is mixed and molded, and then fired, wherein the fired non-linear resistor element is aged by applying a voltage for a certain period of time. A method for manufacturing a nonlinear resistor, characterized by performing the following steps. 2. Aging for a certain period of time is carried out under the condition that the leakage current of the initial nonlinear resistance element increases and then decreases (under the condition that
2. The method of manufacturing a nonlinear resistor according to claim 1, wherein the process is carried out until the increased leakage current decreases to approximately the same value as the initial leakage current value.