JPS5844633A - 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 a circuit breaker, and more particularly to a circuit breaker with improved current-limiting performance during interruption.

FIG. 1(a) is a partially cutaway plan view showing a general circuit breaker), and FIG. 1(b) is a sectional view taken along the line bb of FIG. 1(a). In this figure, (1) is a circuit formed by an insulating enclosure which forms the outer frame of the interrupter; (2) is a fixed contact, which includes a fixed conductor (201) fixed to the enclosure (1) and a fixed contact (201) fixed to the tip of the fixed conductor (201).
02), (3) is a movable contact paired with the fixed contact (2), and a movable conductor (, aO, t) driven by the operating mechanism section (4); It is fixed to the tip of the conductor (301), and the fixed contact (
202), and a movable contact (302) that moves toward and away from the contact point (302). (6) is an arc extinguishing plate that cools the arc A generated when the movable contact (302) separates from the fixed contact (202).

Now, when the movable contact (302) and the fixed contact (202) are closed, the current flows from the fixed conductor (201) to the fixed contact (
202) - Movable contact (302) → Movable conductor (301)
flows along the route of

In this state, when a large current such as a short-circuit current flows through this circuit, the operating mechanism section (4) is activated and the movable contact (30
2) is separated from the fixed contact (202). At this time,
An arc A is generated between the fixed contact (202) and the movable contact (302), and the arc A is generated between the fixed contact (202) and the movable contact (302).
An arc voltage is generated between them. This arc voltage increases as the separation distance of the movable contact (302) from the fixed contact (go2) increases. Moreover, at the same time, the arc A is attracted and expanded in the direction of the arc extinguishing plate (6) by the magnetic force, so that the arc voltage further increases.
' In this way, the arc current line current zero point is reached, the arc is extinguished, and the interruption is completed. During such no-interruption operation, the movable contact (302) and the fixed contact ('202)
) for a short period of time, i.e. the number ξ
A large amount of energy is generated within seconds. for that,
The temperature of the gas inside the enclosure (1) rises, and the pressure also rises rapidly, but this high-temperature, high-pressure gas flows through the outlet (101).
released into the atmosphere.

The circuit breaker and its internal components operate as described above when breaking the circuit breaker, but then the fixed contact (2
02) and the movable contact (302) will be particularly explained. Generally, arc resistance is given by the following formula: Namely.

!几=-19, R: arc resistance 0 p: arc resistivity (Ω・cIL) l: arc length cIL) S: arc cross-sectional area (m) However, in general, at a large current of several KA or more, length l
In a short arc A where is 50131 or less.

The arc space is occupied by metal particles. Moreover, the emission line of this metal particle occurs in a direction perpendicular to the contact surface. In addition, these ejected metal particles have a temperature close to the boiling point of the metal at the contact point at the time of ejection, and as soon as they are injected into the arc space, they are injected with electrical energy and become high temperature and pressure, and become conductive. imbued with sexuality.

It expands in a direction according to the pressure distribution in the arc space and flows away from the conductor at high speed.

The arc resistivity and arc cross-sectional area S in the arc space are determined by the amount of metal particles generated and the direction in which they are released. Therefore, the electrical voltage is also determined by the behavior of the metal particles. Next, the behavior of such metal particles will be explained using FIG. 2.

In FIG. 2, the X-plane shows the opposing surface when the fixed contact (202) and the movable contact (302) come into contact, and the Y-plane shows a part of the contact surface and the conductor surface other than the above-mentioned X-plane. In addition, the loop Z shown by the dashed line in the figure is a fixed contact (20
2) and the movable contact (302), further a and b are the fixed contacts, (202)
, are schematic illustrations of metal particles emitted by evaporation from the X-plane and Y-plane of the movable contact (302), and the emission directions are shown by the respective flows indicated by arrows m and n, respectively. It is the direction of the line.

Such a fixed contact (202)', a movable contact (302)'
) The metal particles a, b released from
From about ℃ to the temperature at which it becomes conductive, that is, s, ooo
The temperature is increased to 20,000°C or higher, and in the process of temperature rise, energy is removed from the anita space, lowering the temperature of the arc space, and as a result, increasing the arc resistance R. In addition, metal particles a from the arc space
The amount of energy taken away by , b increases as the degree of temperature rise of the metal particle increases, and the degree of temperature rise increases at the contact point (202).
, (302) is determined by the position in the arc space and the release path of the metal particles a and b emitted from the metal particles a and b emitted from (302). However, in the conventional circuit interrupter shown in Fig. 2, the metal particles a emitted from near the center of the opposing surface The metal particles emitted from the Y plane take away less energy from the arc space than the metal particles a, that is.

In the range where the metal particles A flow, a large amount of energy is taken away and the temperature of the arc space is lowered, thus increasing the arc resistivity. However, in the range where the metal particles A are flowed, in order not to take away a large amount of energy, the arc space is The temperature decrease is small, and therefore the arc resistivity P cannot be increased, and since the arc is generated from the opposing surface X and the contact surface Y, the arc cross-sectional area S also increases.
Therefore, the arc resistance ratio also decreases.

Since the outflow of energy from the arc space by such metal particles a and b is in proportion to the electrically injected energy, if the metal particles generated between the contacts (202 and 302) If the injection amount is increased, the temperature of the arc space will naturally be greatly reduced, and as a result, the arc resistivity P will be increased and the arc voltage will be large (a<h).
It turns out that it is possible to raise the temperature.

Furthermore, there are major drawbacks of conventional contacts (2) and (3).
A contact point (202), (302) which is generally provided on this Y plane to round off the enlargement of the arc of a person's foot to the Y plane.
There was a risk that the arc person's foot would expand directly at the joint between the conductor (201) e (3ot) and the heat generated at that time would melt the joint material with a low melting point, causing the contact to fall off. .

This invention has been made from the above point of view, and includes at least one pair of contacts consisting of a conductor and a contact fixed to the conductor, and a pressure reflector is provided on each of the conductors so as to surround the outer periphery of each of the contacts. The pressure reflector is an inorganic material formed by heating and pressurizing a base material made of glass cloth, glass mat, or a combination thereof with a binder made of a mixed powder of boric acid, boric anhydride, and zinc oxide. The purpose of the present invention is to provide a circuit breaker that is constructed with a composite insulator to greatly increase the arc voltage, improve current-limiting performance at the time of interruption, and prevent the contacts from falling off. .

Embodiments of the present invention will be described below based on the drawings.

FIG. 3(a) is a partially cutaway plan view showing an embodiment of the circuit interrupter according to the present invention, and FIG. 3(b) is a sectional view taken along line bb in FIG. 3(a). It is. Figure 3(a) t
In (b), the enclosure (1) forming the outer frame of the circuit breaker is made of an insulator, and the outlet (10) is provided on the - side wall.
1). The fixed contact (2) includes a fixed conductor (201) fixed to the enclosure (1) and a fixed conductor (201).
It consists of a fixed contact (202) attached to the tip of the holder. The movable contactor (3) opens and closes with respect to the fixed contactor (2), and includes a movable conductor (301) and a movable contactor attached to the tip of the movable conductor (301) opposite to the fixed contact (202). It is composed of a contact point (302). The operating mechanism section (4) opens and closes the movable contact (3). The arc extinguishing plate (5) extinguishes the arc A generated when the movable contact (302) separates from the fixed contact (202).

Fixed conductor (zof) of the above fixed contact (2), OK l1
The movable conductor (301) of the ll contact (a) has a fixed contact (202) and an I movable contact (302) provided thereon.
A plate-shaped pressure reflection body (6), (7) is attached to surround the outer periphery of the Ark and face the Ark. Both of the contacts (202).

(302) protrudes from the pressure reflector (6), (n,
The pressure reflectors (6) and (7) are made by laminating a base material made of glass cloth, glass mat, or a combination thereof under heat and pressure using a binder made of a mixed powder of boric acid, boric anhydride, and zinc oxide. It is composed of a molded inorganic composite insulator.

Now, in FIG. 3, when the movable contact (302) and the fixed contact (WO2) are closed, the current flows through the fixed conductor (20
1) → Fixed contact (202) → Movable contact (302) → Movable conductor (301), flowing from the power supply side to the load side ◎ In this state, if a large current such as a short circuit current flows through this circuit, the operation mechanism When the part (4) is activated, the movable contact (302
) is separated from the fixed contact (202). At this time, an arc occurs between the fixed contact (202) and the movable contact (302). In this arc person, as shown in Figure 4, the metal particles a and c are reflected by the pressure reflectors (6) and (7), creating a high pressure in the arc space, and as a result, the arc A is effectively It is cooled and the arc is extinguished.

Figure 4 shows the fixed contacts (20
2) and metal particles a, c between the movable contact (302).

It is a schematic diagram of behavior. That is, as can be seen from Fig. 4, the pressure value in the space Q around the contact points (202) and (302) cannot be higher than the pressure value in the space of the Ark himself, but at least the pressure reflection Body (6
)? This value is overwhelmingly higher than that in the case where (7) is not provided. Therefore, the pressure reflector (6) t
The surrounding space Q, which has a considerably high pressure caused by (7), provides a force to suppress the expansion of the space into the arc, and causes the arc person to be "squeezed" into the narrow space K. This means that the metal particles a and c are emitted from the X-plane, which is the opposing surface.
The streamlines m and o such as these are squeezed and confined in the arc space. Therefore, the metal particles a and C emitted from the The arc space is cooled significantly by removing a large amount of energy that cannot be generated.This significantly increases the arc resistivity C, that is, the arc resistance hole, and the arc voltage increases significantly, improving the current limiting performance.

In addition, due to the pressure reflectors (6) and (7)), the legs of the arc person are difficult to expand to the Y-plane, so generally, the contact points (202) and (302) provided on this Y-plane Conductor (201).

This has the advantage that the leg of the arc λ is less likely to directly touch the joint with (301), and as a result, the contact does not come off.

Although the circuit breaker with the structure described above has significantly superior current limiting performance compared to conventional circuit breakers, its characteristics are largely determined by the characteristics of the material that composes the pressure reflector (6) e (7). This is an important issue for the invention regarding material selection for wires.As mentioned in the manual, when a large current such as a short-circuit current flows through the circuit,
The operating mechanism section (4) operates to separate the movable contact (302) from the fixed contact (2f12). At this time, the contact (
An arc occurs between 302) and (202). In order to increase the voltage of this arc and obtain extremely excellent current limiting performance, a large amount of gas is generated from the surface of the material constituting the pressure reflecting plates (6) and (7) due to arc heat, and the arc is It is effective to increase the pressure in the arc space between the contacts (302) and (202) at the same time as cooling, to promote narrowing of the arc and to accelerate the opening speed. It is also important that the surface resistance does not decrease due to decomposition or melting of the surface of the material due to contact with the high-temperature arc.If the surface resistance decreases, the legs of arc A will expand, resulting in complete current limiting. No effect is obtained.

Furthermore, in this type of circuit breaker, the circuit breaker is repeatedly shut off an extremely large number of times.

It is required that the wear and tear of a single material due to arcing is small, that it has good hemorrhoid resistance, and that it does not break due to mechanical or thermal shock strength.

If the wear and tear is large or the contact is damaged, no pressure increase can be achieved in the arc space between the contacts (302) and (202), leading to a decrease in current limiting performance.

As mentioned above, there are a wide variety of conditions that the materials constituting the pressure reflectors (a) and (7) must meet.

By the way, in terms of current-limiting performance, organic materials can be considered as materials that generate a large amount of decomposed gas when exposed to the high temperature of an arc. However, due to its low heat resistance and poor thermal conductivity, the pressure reflector itself will wear out if exposed to high-temperature arcs during heavy current interruptions. There are problems such as deterioration and disappearance, which is a disadvantage in hemorrhoid resistance, or after generation of decomposition gas, carbonaceous substances of decomposition products are precipitated, reducing the resistance of the material surface.

9. Regarding this lifespan, materials made only of porcelain materials, which are typical inorganic materials, have a high melting point and high heat resistance, and even if they come in contact with a high-temperature arc, they will decompose and conduct electricity. It does not produce sexual substances, and there is no wear and tear. In addition, it has good thermal conductivity and does not cause local temperature rises, so there is no drop in resistance at high temperatures and the cooling effect of arc heat is remarkable, equivalent to cooling by gas generated from organic materials. It has excellent current limiting performance. However, because of its low impact resistance, it has a fatal flaw in that it is easily damaged by a single shock caused by a severe breaker or by mechanical impact caused by opening and closing the breaker.

Therefore, in this invention, as a material constituting the pressure reflector, we investigated an insulating material that has both current-limiting performance and bird life resistance, and has good mechanical strength. A material is used as a base material, and granular boric acid is placed between this base material.

A binder made of a mixed powder of boric anhydride and zinc oxide is evenly spread and stacked, heated and pressurized. It was concluded that the material had excellent strength, impact resistance, and machinability, and was used as a material constituting a pressure reflector.

The above-mentioned binding material has a structure that generates evaporated substances such as water vapor by thermal decomposition, and is mainly composed of boric acid, which has binding strength in one heating state.

The boric anhydride chemically absorbs the moisture generated by the thermal decomposition of the acid, and the boric anhydride itself is denatured and reacts with zinc oxide, resulting in a highly binding and stable light source. It converts into a boron compound, completely binds the substrate, and improves water spray and moisture resistance.

The desirable ratio of the base material such as glass cloth or glass mat according to the present invention and the binder is base material: binder = 20~
80% (weight %, same hereinafter): preferably within the range of 80 to 20*, particularly preferably 30 to 70%: 70
It is in the range of ~30-. If the ratio of the binder is less than 20%, the bonding force between the base materials will be insufficient, and if it is more than 80%, it will become brittle.In addition, as for the ratio of the binder composition, boric acid is 20 to 70%.
G, preferably 30-60%, 115
~25 inches, preferably 10-20 inches, zinc oxide 30-5 inches
5 g is preferably in the range of 35 to 509 g. If the amount of boric acid is less than 20 g outside of the above range, the binding force will be poor, and if it is more than 70 g, it will be brittle and have poor moisture resistance.

The insulating material constituting the pressure reflector used in the present invention will be specifically explained below. Six pieces of Asahi Fiber glass mat (0M305FA) with a size of 500 w x 50 G and approximately 75 g each, and the same Asahi Fiber glass cloth (thickness 0.1 g tm)
Two pieces of 500 n x soo III size, each weighing about 65 g, and 45 grams of boric acid by weight,
Seven portions of a binder mixed with 11% boric anhydride and 44% zinc oxide, each portion weighing approximately 55 g, were prepared as raw materials.

First, add 1 portion of the bonding material to 1 sheet of glass cloth.
Spread 5g evenly on each of the 6 glass mats, then spread 55g of the binder in 1 portion on each of the 6 glass mats, stack the 9 mats one after another, and then place a sheet of glass cloth on top of it.
Complete the preparation process - Next, set the raw materials stacked in the previous process in a press equipped with upper and lower heating plates, heat at a temperature of 180°C, and pressurize at a pressure of 100 kg 7 cd. After maintaining the pressure for 10 minutes, the heat source is cut off, water is immediately passed through the heating plate to cool it down, and when the temperature reaches 50°C, the pressure is released and the molded product is taken out to complete the molding. . This molded product is 1
Stepwise heat treatment from 00"Q to 20℃ with door spacing of 00℃,
A laminated insulator having a thickness of 1.5 mm was obtained.

The pressure reflector made of this insulator will not wear out, wear out, or break even when exposed to the high temperature of the arc.
The current limiting performance was also good. Furthermore, unlike organic materials, p-element was not precipitated as a decomposition product, so the surface resistance did not decrease at all.

Similarly, 55 g of boric acid was added to the base material of 12 pieces of glass cloth with a size of 500 tremors x 500 m + 1 and weighing 5 g each.
Prepare 11 portions of 33 g of a binding material mixed with 12 g of boric anhydride and 33 g of zinc oxide,
Laminated molded or 500 m x 5G03
1 sheet of 110 thickness F) 45 parts of boric acid, 11 parts of boric anhydride, 11! A binder mixed with 44 parts of zinc chloride is divided into approximately 158 parts.
The same characteristics were obtained for the other parts obtained by preparing 6 pieces of 1.g and laminating them and molding them.

As described above, the temperature of the pressure reflector made of the above-mentioned insulator increases due to the high-temperature arc, and the boric acid in the binder thermally decomposes and generates moisture, or water vapor gas, so the arc deprives energy. and is extremely effectively cooled. Additionally, due to the generation of water vapor gas, the pressure on the surface of the pressure reflector increases, promoting the arc constriction effect, and at the same time, the pressure applied to the pressure reflector itself also increases, which in turn increases the pressure on the movable conductor. In addition, the opening speed can be increased.

Therefore, the unique effect of the composite material that generates inorganic water vapor gas is added to the effect of the pressure reflector alone, making it possible to greatly increase the arc voltage and obtain extremely excellent current limiting performance.

In addition, due to its excellent current limiting effect, the arc energy is also reduced, reducing consumption caused by high-temperature arcs.

The degree of wear and tear is low, the lifespan is good, and the surface resistance does not decrease.

Moreover, glass fibers such as glass cloth or glass mat also serve as reinforcing materials, so they can withstand thermal and mechanical shocks. In addition, it has good mechanical processability, so it can be easily punched out and will not chip or break.In addition, it does not use asbestos, which is problematic in terms of hygiene and pollution, and can be formed at relatively low temperatures, which saves energy. It also has advantages as a material.

As mentioned above, when glass fiber base materials such as glass cloth or glass mat are laminated and fixed through a binder made of boric acid or a mixed powder of boric acid anhydride and zinc oxide, and when exposed to high temperatures, boric acid By using an inorganic composite insulator that thermally decomposes and generates steam gas, it has current-limiting performance, longevity, and insulation properties.

The purpose is to provide a hygienic and inexpensive pressure reflector that exhibits excellent properties such as impact resistance.

FIG. 5(a) is a side view showing another embodiment of the contacts (2) and (3), and FIG. 5(b) is a side view showing another embodiment of the contacts (2) and (3).
FIG. 3 is a plan view of the contacts (2) and (3) shown in FIG.

That is, the pressure reflector (6) shown in FIG. (7
) is a conductor (202) 1. (302) is provided only on the contact side surface, but as shown in FIGS. 5(a) and (b), the fixed conductor (201), the movable conductor (301)
A pressure reflector (a), (y) may be formed by taping the circumference of the cavity and covering it with a coating or the like.

6(a) is a side view showing another embodiment of the contactor (21, (3)), and FIG. 6(b) is a side view showing another embodiment of the contactor (21, (3)).
1 is a plan view of the contacts (2) and (3) shown in FIG. Namely.

A part of the pressure reflector (6) -t (7) is covered with a fixed contact (202) + a fixed conductor (in the direction away from the discharge port (101) side from one end side of the movable contact (302) as a base point. 201).

A groove (sol) is formed so that the surface of the movable conductor (301) is exposed.
).

(701) is provided - In this configuration, the legs of the arc person run in the groove (601) # (701), and the arc A
By contacting the arc extinguishing plate (6) and being cooled, the breaking performance is improved.

Furthermore, FIG. 7(a) is a side view showing another embodiment of the contact (21e (3)), and FIG. 7(b) is a side view showing another embodiment of the contactor (21e (3)), and FIG.
) is a plan view of the contactor (21, (3)) shown in (801) v (eol) of FIG. 6 @ (601).

(701) The conductor surface exposed from the pressure reflector (a),
The mound is higher than the surface of (y). This configuration allows the arc person's legs to move quickly, and has the advantage of improving the arc interruption performance.As can be seen from the above description, according to the present invention, the arc voltage can be greatly increased Thus, it is possible to provide a circuit breaker that can improve the current-limiting performance at the time of breaker and prevent the contact from falling off.

[Brief explanation of the drawing]

Figure 1(1) is a partially cutaway plan view showing a general circuit breaker, Figure 1(a) is a cross-sectional view taken along line bb of Figure 1(a), and Figure 2 is the circuit of Figure 1. A schematic explanatory diagram of the behavior of metal particles in a circuit breaker, FIG. A cross-sectional view taken along the line bb in (a), Figure 4 is the 3rd
A schematic explanatory diagram of the behavior of metal particles in the circuit breaker shown in the figure, Figure S (al is a side view showing another example of the contactor,
FIG. 5(b) is a plan view of the contact shown in FIG. 5(a), FIG. 6(a) is a side view showing another embodiment of the contact, and FIG. 6(b) is a plan view of the contact shown in FIG. 5(a). A plan view of the contact shown in FIG. 6(a),
FIG. 7(a) is a side view showing another embodiment of the contact;
FIG. 7(b) is a plan view of the contact shown in FIG. 7(a). (2)... Fixed contact, (201)... Fixed conductor,
(202)... Fixed contact, (3)... Movable contact,
(301)...Movable conductor, (302)...Movable contact, (6), (7)...Pressure reflector, (601). (701)... Groove Note that the same reference numerals in the plane indicate the same or equivalent parts. Agent Makoto Kuzuno (1 other person) Figure 1 (a) Figure 1 (b) Figure 2 Figure 4 Figure 3 (a)! Figure 3(b)

Claims (5)

[Claims] (1) It has at least one pair of contact points consisting of a conductor and a contact fixed thereto, and a pressure reflector is provided on each of the conductors so as to surround the outer periphery of each contact, and the pressure reflector is made of glass. A base material made of cloth, glass mat, or a combination of these is made of an inorganic composite insulator that is laminated under heat and pressure with a binder made of a mixed powder of boric acid, boric anhydride, and zinc oxide. A circuit breaker featuring: (2) The circuit breaker according to claim 1, wherein the pressure reflector is a plate-like member provided only on the contact side surface of the conductor. (3) The circuit breaker according to claim 1, wherein the pressure reflector is a covering that surrounds the conductor. (4) At least one pressure reflector is provided with a groove such that the surface of the conductor is exposed in a direction moving away from one end side surface of the contact point. The circuit breaker described in item 3. (5) The circuit interrupter according to claim 4, wherein the exposed conductor surface is raised more than the surface of the pressure reflector.