JPS5840727A - Circuit breaker - 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 The present invention relates to an enclosed circuit breaker, and more particularly to a nine-circuit breaker that improves current limiting performance during interruption of current flow.

A general circuit interrupter will be explained in Fig. 1 (←), (b)K.

Figure 1 (&) is a plan cross-sectional view, and the same figure (b) is the same figure ←) line ■
-This is a diagram of Confucianism in IK. 1II←), (to), the enclosure a) which circuits and forms the outer frame of the interrupter is equipped with a discharge port α01), and the fixed contact (i) is fixed to the enclosure (1). It consists of a fixed conductor (201) and a fixed contact QO fixed to one end thereof.

Furthermore, it is composed of a movable contact (hereinafter referred to as a fixed conductor G!01), a movable conductor (Cl0I) that opens and closes with respect to K, and a movable contact (302) fixed to one end thereof.

The movable conductor (301) is opened and closed by the operating mechanism section (4). A fixed contact (202) and a movable contact (302)
) is provided with an arc extinguishing plate (5) in the arc space between the contacts G! 02), 01
02) has a cutout groove C01) open to the side. now,
Considering the case where the movable contact (30) and fixed contact Q02) are closed, the current flows in the path of fixed conductor (201) → fixed contact Q02) → movable contact C02) → movable conductor (301). .

When a large current such as a short-circuit current flows through this path, the operating mechanism section (4) operates to connect the movable contact (302) to the fixed contact (202).
2) Separate from. At this time, an arc voltage is generated between the fixed contact (202) and the movable contact G? It increases as the separation distance of the movable contact 0102) from 02) increases. At the same time, the arc voltage is further increased as the arc is drawn toward the arc extinguishing plate (5) by magnetic force and extends.

In this way, the arc current reaches a current zero point, the arc is extinguished, and the interruption is completed. During such an interrupted operation, the movable contact C02) and the fixed contact G? 023, a large amount of energy is generated by Arkum in a short period of time, ie, within a few milliseconds. Therefore, the temperature of the gas within the enclosure (1) rises, and the pressure also rises rapidly. This high-temperature, high-pressure gas is released into the atmosphere from the outlet α01).

The circuit interrupter and its internal components operate as described above upon interruption, but then the fixed contacts (20
The operations of 2) and movable contact C02) will be particularly explained.

Generally, arc resistance R is given by the following formula.

! R=p − However, R: Arc resistance (Ω) P: Arc resistivity (Ω・cm) J: Arc length 1) 1: Arc cross section (d) However, generally, at large currents of several X μm or more, In a short arc with an arc length l of 50 mm or less, the arc space is occupied by the metal particles of the conductor on whose surface the legs of the arc are present.

However, this emission of metal particles occurs in a direction perpendicular to the conductor surface. Furthermore, the ejected large metal particles have a temperature close to the boiling point of the conductive metal at the time of ejection, and as soon as they are injected into the arc space, they are heated to high temperature and high pressure due to the injection of electrical energy. It becomes conductive and flows away from the conductor at high speed while expanding in nine directions according to the pressure distribution in the arc space. The arc resistivity p and the arc cross-sectional area - in the arc space are determined by the amount of metal particles generated and the direction in which they are released. Consequently, the arc voltage is also determined by the behavior of such metal particles.

Next, the behavior of such metal particles will be explained using FIG. 2.

In Fig. 2, contact points (202), (302)
One surface of each of the contacts (20 and (302)) is the opposing surface when they come into contact, and the contact (2oz) and (3G powder O! surfaces are the contact surfaces other than the first surface and one of the conductor surfaces). Show part.

The circle z shown by the dashed-dotted line in Figure 9 is the contact point (202)
.

(302) shows the outer shell of arcum generated between the metal particles a and metal particle S, and the contact point Gi! 02)
.

This figure schematically shows metal particles emitted from the X-plane and Y-plane of (302) by evaporation, etc., and the emission direction is the direction of each streamline indicated by arrow m and arrow n, respectively.

The metal particles 1.1 released from such contacts (202) and (302) rise from the boiling point temperature of a conductive metal, which is about s, ooo degrees Celsius, to the temperature at which it becomes conductive, that is, s. , ooo°C or higher, or even higher to about zo, ooo°C, and in the process of external heating, energy is removed from the arc space, lowering the temperature of the arc space, and as a result increasing the arc resistance R. Note that metal particles 1. ′
The amount of energy removed by b is large as the degree of temperature rise of the metal particles is large;
, (302) is determined by the position in the arc space and the emission path of the metal particles 1.111. However, in the conventional circuit breaker shown in the second wJ,
Metal particles a emitted from near the center of the X-plane take away a large amount of energy from the arc space, but metal particles emitted from the Y-plane, which is a part of the contact surface and conductor surface, have a larger amount of energy than metal particles a. The amount of energy taken away from the arc space is small.

That is, in the range where the metal particles a flow, the metal particles 1 absorb a large amount of energy, lowering the temperature of the arc space and increasing the arc resistivity. However, because it does not take away a large amount of energy, the temperature in the arc space decreases little, and therefore the arc resistivity P cannot be increased.Moreover, since the arc is generated from the 1st and The area increases and the arc resistance decreases.

Since the outflow of energy from the arc space due to such metal particles is balanced with the electrical injection energy, if we increase the amount of metal particles generated between the contacts injected into the arc space, It turns out that it is possible to greatly reduce the temperature of the arc space, and as a result, increase the arc resistivity and greatly increase the arc voltage.

In addition, a major drawback of conventional contact conductors is that the arc leg tends to expand directly to the junction with the conductor, which is often provided on the Y plane, due to the rounding of the arc leg expansion to the Y plane.
There are six important points to consider: this heat melts the joining member with a low melting point, and there is a risk that the contact will fall off.

SUMMARY OF THE INVENTION An object of the present invention is to provide a circuit interrupter which has a high arc voltage, has good current-limiting performance during interruption, and is free from the risk of contacts falling off. That is, this invention:
The conductor surface around the contact point is covered with a pressure reflector made of an inorganic composite insulator that generates decomposition gases other than water vapor when in contact with the high-temperature arc, and when an arc occurs, metal particles are forcibly injected into the arc space. , the decomposed gas contributes to the arc cooling effect, the squeezing effect, etc., thereby improving the current limiting performance.

Next, an embodiment of the present invention will be described with reference to FIGS. 3 and 4.

Figure 93 (a) is an overall plan sectional view of the circuit interrupter with a part cut away, Figure 93 (1)) is an overall side sectional view taken along line 1-1 in Figure 93 (a), and Figure 4 is a pressure reflection It is an explanatory diagram showing the action of the body.

(1) is an enclosure made of an insulator, which forms the outer frame of the circuit interrupter, and is provided with a gas outlet α01). The fixed contact (2) consists of a fixed conductor (201) and one end thereof Kl1, and consists of nine fixed contacts (20), and the nine movable contact (3) is fixed to the movable conductor (i401) and one end thereof. The movable contact (3) is composed of a fixed contact (illustrated An arc extinguishing plate (6) is provided to surround the arc space between the movable contactor (3) and the movable contactor (3).

This arc extinction [(5) is such that one end thereof is the contact point C2Oa
.

0102) side and has nine notches 11Iφ01). Pressure reflectors (6) and (7) are attached to the fixed contact (2) and the movable contact (3), respectively.

These pressure reflectors (6), (7) have through holes (601), (701), respectively, and the fixed contacts (20) are inserted into the through holes (601), (701).
2) , (302) is penetrated. Pressure reflector (6
).

(7) is made of an inorganic composite insulator (described later), and various methods of attachment to the contacts (2) and (3) may be selected as desired.

In Figures 3 and 4, pressure reflectors (6) and (7) are shown.
) as a flat pressure reflecting plate and the contact point (202),
e102) in which only the surrounding conductor surface is coated is shown.

In such a thing, each contact point (202), (3
02) Metal particles between each other behave as follows.

In other words, contact G? 02), (302) The pressure value in the surrounding space q cannot be greater than the pressure value in the space of the arc cross section, but at least the pressure reflector (
6) , (The pressure reflector (6) shows an overwhelmingly higher value than the case where η is not provided.
The surrounding space q, which is generated by (7) and has a nine-phase alK high pressure, exerts a force that suppresses the expansion of the space of the arcum 9, thereby squeezing the arcum into a narrow space. In other words, the flows am, O of round metal particles fL, e, etc. emitted from one surface, which is the opposing surface, are squeezed into the arc space and confined therein. Therefore, the metal particles a and c emitted from one surface are effectively injected into the arc space, and as a result, a large amount of effectively injected metal particles a and a are removed from the arc space compared to the conventional device. , which takes away an incomparably large amount of energy, significantly cools the arc space. therefore,
The resistivity P, that is, the arc resistance R is significantly increased, and the arc voltage is significantly increased.

In addition, the pressure reflectors (6) and (7) make it difficult for the legs of the arcum to expand to the Y plane, and generally the contacts (202) - (302) and the conductor (20
1).

It becomes difficult for the arc 0 foot to directly touch the joint of (301). As a result, there is an advantage that contact dropout does not occur.

In addition, in Fig. 3, the movable contact G (02) and the fixed contact (
202) are closed, the current flows through the fixed conductor (gel
)→fixed contact (202)→movable contact (302)→movable conductor (301), from the power supply side to the load side. In this state, when a large current such as a short-circuit current flows through this circuit, the operating mechanism section (4) is actuated to separate the movable contact 002) from the fixed contact (202). At this time, fixed contact G
? 02) and the movable contact G1102). In this arc, as shown in Figure 4, the metal particles are reflected by the pressure reflectors (6) and (7), creating a high pressure in the arc space, and as mentioned above, a large amount of energy is taken away from the arc space. As a result, the arc is effectively cooled and extinguished.

The circuit breaker with the structure described above has significantly superior current limiting performance compared to conventional circuit breakers, but its characteristics depend on the characteristics of the materials constituting the pressure reflectors (6) and (7). The selection of materials is an important issue for this beak, as it is largely influenced by

In other words, there are a wide variety of conditions required for the pressure reflectors (6) and (7), but among them, the pressure in the arc space between the contacts (202) and (302) should be increased when an arc occurs. Effective arc embedding and arc cooling; The material itself does not wear out or wear out even after repeated operations, and has good lifespan; and mechanical and thermal shock resistance. It is important that it has excellent strength and does not break, and that its surface does not decompose or melt and reduce its surface resistance even when it comes into contact with a high-temperature arc. If even one of these four conditions is lacking, the pressure in the arc space cannot be increased, and the legs of the arc expand, resulting in a decrease in current limiting performance.

Therefore, various considerations were made in selecting appropriate materials for the pressure reflectors (6) and (7), which will now be explained step by step.

First, we attempted to improve the current limiting performance by increasing the pressure in the arc space when an arc occurs to narrow the arc and cool the arc. In order to carry out both the above-mentioned squeezing and cooling, it was thought that an organic material that generates a large amount of decomposed gas upon contact with a high-temperature arc would be suitable.

In reality, pressure reflectors made only of organic materials had excellent characteristics. However, when exposed to high-temperature arcs during interruptions or direct interruptions with large currents, the material itself can be 100% gasified, depending on the composition. The pressure reflector itself can wear out and disappear. There are problems such as shortcomings in terms of durability, lifespan, and carbonaceous decomposition products that precipitate after generating decomposition gas, reducing the resistance of the material surface.

Therefore, in order to maintain the lifespan while relying on the ability of organic materials to generate a large amount of gas in terms of current limiting performance, and to reduce the amount of carbon that decomposes and precipitates, inorganic materials such as asbestos wool, glass fiber, etc. A composite material consisting of a mica sheet base material and an organic material such as a resin binder was investigated.

However, this composite material showed good current limiting performance in the region of small breaking capacity, and the carbonaceous precipitation was significantly reduced compared to the organic material alone, indicating good properties. In the capacity range, there was a large amount of wear and tear, and there were problems with longevity.

Therefore, we concluded that materials that rely on organic materials as materials for pressure reflectors would not be able to achieve the objective in terms of overall properties. The selection was carried out.

Materials that directly generate carbon dioxide gas, fluorine gas, nitric acid gas, etc. as gas generating materials through thermal decomposition of inorganic materials, such as carbonates such as calcium carbonate and magnesium carbonate;
There are fluorides such as aluminum fluoride and calcium fluoride, and nitrates such as magnesium nitrate.

Therefore, using these inorganic materials, we obtained an inorganic composite insulator consisting of the following molded product, which was used as a pressure reflector. ■ Synthetic flake-like total fluorine mica 60-100 mesh powder 407% (capacity ratio and below are the same), aluminum fluoride powder 3 (1'%, PbO0.6 mol, KarasuO10,
Mixed powder 801 with 307% powder of 200 mesh or less of low melting point glass having a composition ratio of 6 mol, mlps 0.4 mol is used as a raw material, and this is mixed with an area of 1001111
Filled into a mold of X100 tone and heated in an electric furnace at 430℃ for 3
After heating for 0 minutes, press while heated! ri 1k
A molded product with a thickness of 1.5 ml obtained by holding the mold at a pressure of R/d for 20 minutes and then demolding.

■20f flaky natural gold mica with 60 to 100 meshes
, Magnesium carbonate powder of 100 mesh or less 161
．． A mixed raw material of 12f of boric acid, 4f of boric acid anhydride, and 8g of zinc oxide was filled into a gold chamber with an area of 100ff x 100III, and pressed at a temperature of 180℃ and 150K.
A molded article with a thickness of 1.5111 mm obtained by heating and pressing under the conditions of g/d.

■A mixture of 100 parts by weight of asbestos wool, 100 parts by weight of a 50% aqueous solution of monobasic magnesium phosphate, and 50 parts by weight of calcium fluoride powder of 100 mesh or less was thoroughly mixed with a crusher. Using 50 f as raw material, the area 100
A molded product with a thickness of 1.5 g obtained by filling a WX100III mold and heating and press-molding it with a hot press at 160' 0.100 kg/d.

According to the pressure reflector made of the above-mentioned inorganic composite insulator, the temperature rises when it comes into contact with the high-temperature arc, and the arc releases energy because it emits inorganic decomposition gas, that is, fluorine gas or carbon dioxide gas. As the decomposition gas is generated, the pressure on the surface of the pressure reflector increases, promoting the arc embedding effect, and at the same time increasing the pressure on the pressure reflector itself. It was confirmed that the pressure applied to the movable conductor increases the opening speed.

Note that, in addition to the above-mentioned mica-based or asbestos-based base materials, glass fiber-based, ceramic fiber-based base materials, etc. may be used as the inorganic base material to obtain the same properties. In addition, as the inorganic binder, the above-mentioned low melting point glass type is used.

In addition to boric acid-based and metal phosphate-based base materials, a bonding effect can also be obtained by using a cement-based binder that can be cured at low temperatures.

As mentioned above, by using an inorganic composite insulator that thermally decomposes and releases inorganic decomposition gas9 when it comes into contact with a high-temperature arc, current-limiting performance, lifespan, insulation properties, thermal and mechanical shock resistance are improved. 5. Next, FIG. 5 (1) is a side view showing pressure reflectors (6) and (7) according to other embodiments. ('b) is a plan view of the same figure. That is,
Pressure reflector (6) shown in Jg3 and Figure 4,
(n is a flat plate shape, but is not limited to this. As shown in FIGS. Pressure reflector (6), (7)
may be provided.

Fig. 6 (←) is a side view showing pressure reflectors (6) and (7) according to still another embodiment, and Fig. 6 (color) is a plan view of the one shown in Fig. (1). In other words, the contact points CO and (
Grooves (602) and (702) are provided starting from one side of the 30-metal wire, extending in the direction of arc travel, and the conductors (201) and (301) are formed from these grooves (602) and (702). The surface is exposed. According to this, when an arc occurs, the foot of the arc connects the groove <602>, (702) to the contact point (202).
, (302), the arc easily comes into contact with the arc-extinguishing plate (5)], thereby increasing its cooling effect and improving the breaking performance.

Further, FIG. 7 (- is a side view showing pressure reflectors (6) and (7) according to still another embodiment, and is a plan view of the same figure). That is, the pressure reflectors (6), (7) have contacts (202),
Grooves (602), (7
02), and from these grooves (602), (702), the conductor (201), (301) O surface is bulged out from the surface of this pressure reflector (6), (7) and is round. . According to this, when an arc occurs, the legs of the arc pass through the bulges (801) and (901) more than quickly, and the present invention has much higher current limiting performance than the conventional one. and a safe circuit interrupter can be obtained. In particular, according to the present invention, the surface of the VSO conductor around the contact point of the electrical contact is covered with a pressure reflector, and furthermore, this pressure reflector covers the inorganic fibers in contact with the flaky material and the high-temperature arc, and the surface of the VSO conductor around the contact point of the electric contact is covered with a pressure reflector. Since it is composed of an inorganic composite insulator made of a mixture of inorganic powder that generates decomposed gas and an inorganic binder, the metal particles emitted from the contact point can effectively fill the arc space when an arc occurs. In addition to the effect of the pressure reflector alone, which significantly cools the arc space by narrowing down the arc, the unique effect of the inorganic composite material, which generates decomposition gas other than inorganic water vapor when in contact with the arc, acts additively. .

Therefore, it is possible to greatly increase the arc voltage and obtain extremely excellent current limiting performance.

Moreover, since such an excellent current limiting effect is achieved, the arc energy is small and the high temperature arc has less influence on damage and wear of the pressure reflector. At the same time, the inorganic fibers and flakes of the inorganic composite material that make up the pressure reflector, as well as the inorganic base material, function as reinforcing materials or backing materials against thermal or mechanical impact forces, absorbing instantaneous impacts. Helpful.

Therefore, due to these mutual effects, the life expectancy of the pressure reflector is improved, and its surface resistance does not deteriorate.

[Brief explanation of the drawing]

Figure 1 (&) is a plan sectional view showing a general circuit interrupter;
The same figure (b) is a side sectional view taken along line 1-1 in figure 1 (1), figure 2 is a schematic explanatory diagram of the behavior of metal particles in the circuit interrupter of figure 1, and figure 3 (→ is a plan cross-sectional view showing a circuit breaker according to an embodiment of the present invention, and FIG.
FIG. 4 is an explanatory diagram showing the action of the pressure reflector of the circuit breaker in FIG. 3, and FIG. 5 (IL) is an electric contact according to another embodiment of the present invention. 6(b) is a partial plan view of FIG. 6(a), FIG. 6(a) is a partial side view of an electric contact according to still another embodiment of the present invention, FIG. 7 ←) is a partial side view of an electric contact according to still another embodiment of the present invention, and FIG. 7 C) is a partial plan view corresponding to FIG. 7 ←). (2)...Fixed contact % (201)...Fixed conductor, (202)...Fixed contact, (3)...Movable contact, (aOX)...Movable conductor, (302) ...Movable contact, (6), (7)...Pressure reflector, (602
), C702) - Groove, QIOI), (90
1) "" bulging part, A-7-k Note that in the drawings, the same reference numerals indicate the same or equivalent parts. Agent Makoto Kuzuno (1 other person) 1Q (a) Figure 1 (b) Figure 2 Figure 4 Procedural amendment (voluntary) 1. ? Mr. Commissioner of the License Agency 1, Indication of the case Patent application 16-13i? ? of
s No. 2, Name of the invention, IIF device 3, Person making the amendment 6, ``Detailed description of the invention'' column of the specification to be amended. 1 amendment included in the specification: (1) Page 6, line 11 and same page cylinder, line 12, 0 irises r a
, oooooC" and Ai are corrected to "r 5.000°C."that's all

Claims (1)

[Scope of Claims] a) A pair of electrical contacts consisting of a conductor and a contact fixed to the conductor are provided with a pressure reflector on the conductor so as to surround the outer periphery of the contact. This pressure reflector is an inorganic composite insulation made of a mixture of inorganic fibers or flakes and inorganic powder that generates decomposition gases other than water vapor when in contact with a high-temperature arc, and molded with an inorganic binder. A circuit interrupter made of materials. (2) The circuit interrupter according to claim 111, wherein the entire surface of the conductor is covered with a pressure reflector. (3) The circuit interrupter according to claim 1, wherein the pressure reflector is made of a plate-like material that covers only the surface of the conductor around the contact. (4) The pressure reflector is provided with a groove that starts from one side of the contact and extends in the direction of arc travel.
The circuit interrupter according to any one of claims 1 to 3, wherein the conductor surface is exposed from the groove. (5) The circuit interrupter according to any one of claims 1 to 3, wherein the conductor surface is bulged from the surface of the pressure reflector through the groove of the pressure reflector.