JPH061655B2 - Vacuum and breaker - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a low surge vacuum breaker and a breaker, and more particularly to an electrode structure with improved large current breakage and breakage characteristics.

[Technical background of the invention and its problems]

The characteristics required for vacuuming and circuit breaker include (a) high withstand voltage, (b) high current and good disconnection, and (c) low surge. However, these characteristics often exist in the contact material, and it is actually difficult to obtain a contact material satisfying all of these characteristics. In particular, it has been conventionally considered difficult to achieve both low surge characteristics and large current and disconnection performance.

However, the applicant has proposed in Japanese Patent Application No. 52-140754 a low surge vacuum breaker using a Ag-WC low surge contact material and a breaker, and found a clue to increase the capacity of a low surge. Further improvement in performance is demanded. In other words, the number of cases in which an inductive load such as a large capacity motor is opened and closed is increasing in recent years due to the complexity of the system or a vacuum switch or a breaker, and it is necessary to solve the problem of switching surge depending on the applied load. In the case of such loads, harmful surges have been conventionally suppressed by vacuuming or adding a surge absorber outside the breaker. However, adding a surge absorber to the outside poses a problem that the vacuum and the breaker become large.

Fig. 2 shows the electrode structure of a conventional vacuum breaker and disconnector using Ag-WC contact material, where 1 is a contact and the coil 2 is placed behind it, so that the arc parallels when the current is cut or cut. It has an electrode structure to which a magnetic field is applied, that is, a so-called longitudinal magnetic field electrode structure. Reference numeral 3 denotes a reinforcing plate which prevents the contact 1 from being cracked or the coil 2 from being deformed by a mechanical impact force when the electrodes are opened and closed, and is made of a stainless steel material that does not easily affect the magnetic field generation strength. Such a material having high electric resistance is used. As is well known, the phenomenon of vacuum break or breaker breaks the metal vapor generated by the arc at the time of current break or break by using the diffusion action in vacuum to extinguish a large amount from the electrode during the arc generation period. Of metal vapor is generated. At the same time as the metal vapor is generated, it diffuses into the surrounding vacuum space and adheres to the low temperature portion of the electrode and condenses, but the vapor pressure is relatively high during the arc generation. The energy supplied to the arc becomes zero at the current zero point, but the vacuum breaker, the breaker, and the breaking performance are greatly influenced by the metal vapor remaining at the current zero point. After the current zero point, the residual metal vapor diffuses at a high speed and the metal vapor pressure drops, but during this period, a re-electromotive force is applied between the electrodes, so it is sufficient to withstand this rise in re-elevation voltage. If the vapor pressure cannot be lowered, the current cannot be turned on or cut off. Therefore, in order to increase the cutting performance and the cutting performance, it is necessary to further suppress the generation of metal vapor and the action of adhesion and condensation of residual metal vapor, and the general method is to increase the electrode diameter. .

However, the conventional electrode structure shown in FIG. 2 has the following drawbacks and is a major cause of the failure to improve the cutting performance.

(1), Ag-WC low surge contact is a sintered contact, and it is difficult to manufacture one with a large contact diameter. That is, WC powder is press-molded when making a contact, but the larger the diameter of the contact, the more the pressing force becomes a problem. Further, when the contact diameter becomes large, it becomes difficult to apply the molding pressure evenly, which adversely affects the quality stability.

(2), Ag-WC low surge contacts have high hardness and good withstand voltage characteristics, but on the other hand, they have the drawback of being damaged. Vacuum breaks and circuit breakers that require large currents and breaks also have large mechanical impact when opening and closing. Although the reinforcing plate 3 is used in FIG. 2 in order to prevent cracking or deformation of the contacts, the reinforcing method becomes more difficult as the contact diameter increases.

(3), Ag-WC low surge contacts have excellent low surge characteristics, but they are expensive because Ag is the main component, and the larger the contact diameter, the less economical.

[Object of the Invention]

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide a high-quality vacuum breaker or breaker that enables low surge and large current breakage.

[Summary of the Invention] According to the present invention, the above-mentioned object is an electrode structure in which a small current switching part is formed by using an Ag-WC low surge contact having a small contact diameter and a large current breaking part using a Cu electrode is separated. The Cu electrode part
Vacuum cleaner and breaker characterized by Ag plating.

Example of Invention

In the present invention, the vacuum breaker or breaker is generally constructed by providing a pair of electrodes in a vacuum container whose both ends are closed by an insulating cylinder, and the arc shield surrounds the electrodes. Although it is arranged, FIG. 1 shows an embodiment of a power transmission part structure which is a main part of the present invention. 2 in FIG.
It is a contact that uses Ag-WC low surge contact material and is characterized by being smaller than the contact diameter shown in the conventional example of FIG. 14
Is a copper electrode with a diameter larger than the contact 10, and its surface is
Ag is applied. Coil 12 behind Cu electrode 14
Is arranged so that a magnetic field parallel to the arc is applied when the current is turned on or off, which is a so-called longitudinal magnetic field electrode structure. 13
Is a reinforcing plate that prevents the coil 2 and the copper electrode 4 from being deformed by a mechanical impact force when the current is switched.

According to the above configuration, the arc when the current is turned on or off is Ag-
It is possible to find from the arc observation that the WC low surge contact 10 can be transferred to the Cu electrode 4 with Ag plating, and as a result, the arc can be easily spread over the entire electrode 14 and the large current can be turned on or off. It was When the Cu electrode without Ag plating was used, the arc when current was turned on or off did not transfer from the contact to the Cu electrode as described above, but the arc migrated by using the Cu electrode with Ag plating. According to the inventor's knowledge, the reason for this is presumed to be due to the difference in arc voltage. That is, the stable arc voltage of the Ag-WC low surge contact is about 20 ^V, and the arc voltage of one Cu electrode is about 30 ^V. Below this, it is considered that the arc transfer can be prevented if Ag plating is not applied. .

On the other hand, by applying Ag plating to the Cu electrode, it is considered that an arc voltage almost equal to that of Ag-WC was obtained, and it is considered that the arc was easily transferred. Therefore, unlike the conventional method, Ag-WC with a large contact diameter does not require a low surge, and because of the economy of the contact diameter and manufacturing quality, low surge vacuum and breakage of the disconnection and improvement of disconnection performance can be improved. Although it could not be measured, the present invention has a great effect that a large-capacity low-surge vacuum breaker or breaker excellent in breakage performance can be provided. In addition, since the contact diameter can be small, the contact can be easily manufactured, and the molding pressure can be easily controlled during press molding of the contact, so that the molding pressure can be evenly applied, and the infiltrated portion of Ag during sintering can be equalized. High quality contacts can be used. Also, since the contact diameter can be small, expensive Ag
There are many advantages such as the need to use a large amount of a vacuum cleaner and the provision of a vacuum breaker and a breaker, which are excellent in economic efficiency.

The present invention shows one embodiment, and various applications are possible without changing the gist thereof. That is, in the embodiment, the case where one contact is used for the electrode is shown, but the effect is the same even when a plurality of contacts are used. Further, in the embodiment, the case where the invention is applied to the longitudinal magnetic field electrode is shown, but the application to the conventional spiral electrode (not shown) can be expected to bring about the effect similar to that of the embodiment.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a vacuum breaker and a circuit breaker which are excellent in low surge, large current and cutting performance.

[Brief description of drawings]

FIG. 1 is an electrode structure diagram of a vacuum breaker and a circuit breaker showing an embodiment of the present invention, and FIG. 2 is an electrode structure view of a conventional vacuum breaker and a circuit breaker. 10 ... Contact 12 ... Coil 13 ... Reinforcement plate 14 ... Cu electrode 15 ...

Claims (2)

[Claims] 1. A vacuum or breaker having a pair of electrodes provided in a vacuum insulating container, wherein the electrodes have a silver material on the surface of a copper material, and a part of the surface of the electrodes has a diameter smaller than that of the electrodes. Vacuum breaker and breaker characterized by having one or more contacts made of low surge material. 2. A vacuum breaker or a breaker according to claim 1, wherein the contact material is made of Ag-WC as a main component.