JPS5983321A - Switch - 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 suppressing pressure within a container of a switch. Note that the term "switch" used in the present invention particularly refers to a circuit breaker, a current limiter, an electromagnetic switch, etc., which generates an arc within a container, usually a small container.

In the following, a circuit breaker will be explained as an example.

Figures 1 to 3 are cross-sectional views showing conventional circuit breakers.
Each shows a different operating state.

(1) is a cover, (2) is a base, and the cover (1) and base (2) constitute a container (3). (4) is a fixed contact, and a fixed contact (6) is attached to one end of the fixed conductor (5).
), and the other end is a terminal portion to be connected to an external conductor (not shown). (7) is a movable contact, and has a movable contact (9) at one end of its movable conductor (8) opposite to the fixed contact (6). αQ is a movable contactor device (the movable arm is fixed to the crossbar (→) and is configured to be opened and closed between each pole. αe is a toggle link mechanism, consisting of an upper link α force and a lower link O. One end of the upper link (1'5 is attached to Credo iva*,
Further, the other ends are connected to one end of the lower link θ frame, respectively, with shafts (E) and (N). The other end of the lower link (g) is connected to the movable arm (g) of the movable contact device θ.

(The station is a tilting operation handle. (The illusion is an operating spring, which is suspended between the shaft of the toggle link mechanism 0 and the above operation handle (E). (I), (C) are thermal and electromagnetic tripping mechanisms, respectively, which, when activated, rotate the bimetal/V) and movable iron core (respectively) in the counterclockwise direction.

(η is a latch whose one end is locked to the trip bar (4) and the other end is locked to the cradle α.

When the operating hand IL/(2e is turned to the closed position with the Credo) van locked to the latch handle, the toggle link mechanism Q6 will extend and the shaft ■◇ will be locked to the Credo/I10.1, making the movable contact (9) is joined to the fixed contact (6). This state is shown in FIG. Next, when the operating handle is tilted to the open position, the toggle link mechanism α is bent to open the movable contact (9) from the fixed contact (6), and the movable arm (1)
■ is stopped at (Fredol axis). This state is shown in FIG.

Furthermore, when an overcurrent flows through the circuit in the closed state shown in Fig. 1, the thermal tripping mechanism) or the electromagnetic tripping mechanism (phantom) is activated and the engagement between the credo 1vα and the latch handle is released, causing the credo 1vα to disengage. Turn clockwise around the axis (g)
The va moan rotates and is locked on the stopper shaft 0]). The connection point between the upper link α force and the upper link α force is the above-mentioned operating spring (2
), the toggle link mechanism M is bent by the spring force of the operating spring (4), and each pole is interlocked with the cross bar 04 to perform automatic shutoff.

This state is shown in FIG.

Next, the behavior of the arc that occurs when the circuit breaker interrupts the current will be explained.

Now, when the movable contact (9) and the fixed contact (6) are in contact, the power is transferred from the power supply side to the fixed conductor (5).
), fixed contact (6), movable contact (9) and movable conductor (
8) and is sequentially supplied to the load side. In this state, when a large current such as a short circuit current flows through this circuit, the movable contact (9) is separated from the fixed contact (6) as described above. At this time, the fixed and movable contacts (6),
An arc is generated between the fixed and movable contacts (6) and (9), and an arc voltage is generated between the fixed and movable contacts (6) and (9). This arc voltage is transferred from the fixed contact (6) to the movable contact (9).
As the separation distance increases, the arc rises, and at the same time, the arc (goods) is attracted and elongated by the magnetic force in the direction of the arc-extinguishing plate a, so that it rises further. In this way, the arc current reaches a current zero point, the arc is extinguished, and the interruption is completed. However, this huge amount of arc energy that is injected will eventually escape completely outside the container in the form of thermal energy, but it will temporarily increase the temperature of the gas inside the container. This means that the gas pressure must be increased rapidly.

This may lead to deterioration of the insulation inside the circuit breaker, an increase in the amount of sparks emitted to the outside of the circuit breaker, resulting in a power short circuit accident, destruction of the circuit breaker body, etc.

Next, we will discuss the energy consumption mechanism of the arc, which was the basis for creating this invention.

FIG. 4 shows an arc A generated between contacts (4) and (7). In the figure, T indicates the flow of thermal energy conducted from the arc A to the contact and escapes, m indicates the flow of energy of the metal particles 6 escaping from the arc space, and ■ indicates the flow of energy due to light escaping from the arc space.

In Figure 4, the energy injected into arc A is
Most of it is consumed by the three energy flows mentioned above, T, m, and H. Of ε, heat escape T to the electrode is minute, and most of the energy is carried away by m and R. Conventionally, in the energy consumption mechanism of arc A, m in the figure was overwhelming, and the energy of R was almost ignored, but recent research by the inventors has revealed that It has now become clear that the consumption of energy, that is, the energy consumed by light, is so enormous that it reaches about 70% of the energy injected into the arc A.

In other words, the consumption of energy injected into the arc can be analyzed as follows.

Pw=V-engine=PIC+Pth+PRPK=
Lmv" + m -Cp -T However, PW: Instantaneous injection energy ■: Arc voltage engineer: Current ■・■: Instantaneous electric energy μPK injected into the arc:
Instantaneous energy consumption 'mv' carried away by metal particles: Instantaneous energy consumption m-0p-T when metal particles of mg fly away at speed V: Gaff (metal particle gas) with constant pressure specific heat Op Instantaneous energy consumption carried away when escaping at temperature T pth: Instantaneous energy consumption escaping from the arc space to the contact through heat conduction PR: Instantaneous energy consumption radiated directly from the arc by light The above consumption amount varies depending on the contact shape and arc length, but for an arc of 10 to 20 mm, -PK =
16-20%, Pth = 5chi, PR = 75
~85%.

Next, FIG. 5 shows the situation when the arc A is confined in the container (3). When the arc A is confined in the container (3), the space inside the container (3) is filled with metal particles and becomes hot. In particular, the above-mentioned state is strong in the gas space Q around the arc positive column A (the space Q indicated by diagonal lines in the figure). Now, the light emitted by the arc A is emitted from the arc positive column A, is irradiated onto the wall of the container (3), and is reflected. The reflected light is scattered, passes through the high-temperature space filled with metal particles, and is irradiated onto the wall again. This process is repeated until the amount of light reaches zero. The path of light during this time is R in the diagram.
a-+R'l)-+R(3→Rd).

In the above process, the light emitted from arc A is consumed at the following two points.

(1) Absorption at the wall surface (2) Absorption by the arc space and surrounding (high temperature) gas space, that is, absorption by the gas space, and the light emitted from arc A ranges from the far ultraviolet of 2000 Å or less to the far infrared of 1 μm or more. All wavelength ranges consist of ruts, continuous spectra, and line vectors p. Even if the surface of a typical container wall is black, it only has the ability to absorb light within the range of about 4,000 to 5,500 people, and in other ranges,
Only a portion of it is absorbed, and most of it is reflected. However, absorption in the arc space and surrounding high temperature gas space is as follows.

One wavelength λ in a gas space with a uniform composition and temperature of length L
The amount of light absorbed by the gas space when irradiated with light can be calculated as follows.

Work a=Aθ・n−L work in ・・・・・・
...(1) Equation a : Absorbed energy by gas A : Absorption probability in : Irradiated light energy n : Particle density L : Optical path length through which light passes. However, equation (1) shows the absorption for a specific wavelength λ. Indicates the amount of energy. Ae is the absorption probability for a specific wavelength λ,
It is a function of wavelength λ, gas temperature, and particle type.

Regarding equation (1), according to the teachings of quantum mechanics, the absorption coefficient Ae is greatest for gases that are in the same state as the light source gas that emits light (i.e., the type of particles and temperature are the same) for both continuous and line spectra. It will have a value. That is, the light emitted from the arc space is absorbed most in the arc space and the surrounding gas space.

In equation (1), the light absorption energy profile Ia is proportional to the optical path length. As shown in Fig. 5, when the light from the arc space is reflected by the wall surface, L in equation (1) increases by the number of reflections. The amount of light energy absorbed will increase.

This means that the energy of the light emitted by the arc A is eventually absorbed by the gas in the container (3), thereby increasing the temperature of the gas and the pressure of the gas.

Therefore, the premise of this invention is to use a specific material to effectively absorb the light energy, which reaches about 70% of the energy injected into the arc. fibers, nets, and highly porous materials with an apparent porosity of 35% or more that effectively absorb the light emitted by the arc at specific locations that receive the energy of the light.
By arranging a material consisting of a seed or a composite of two or more types, a large amount of light inside the container is absorbed, thereby lowering the temperature of the gas space and thereby reducing the pressure.

The above-mentioned fibers are selected from inorganic materials, metals, composite materials, woven materials, nonwoven materials, etc., but since they are installed in a space exposed to high-temperature arcs, all of them have thermal strength. Must be.

Further, as the mesh, in addition to inorganic materials, metals, composite materials, etc., the mesh may also be made of multiple layers of thin wire mesh, wire mesh, etc.

In the case of this net as well, it is necessary to select one that has thermal strength.

Among the above-mentioned fiber and net materials, inorganic materials such as Cefmic, carbon, and Amepest are preferred, and those plated with each are also applicable.

Porous materials are generally materials with a large number of pores within a solid structure, and exist in a wide range of materials such as metals, inorganic systems, and organic materials. One type is sintered and solidified at the contact points between solid particles, and the other type is mainly composed of pores and the partition walls forming the pores are made of solid material. Note that the material here refers to the original material before shape processing, which is not shaped into a shape.

Further classification can be divided into those in which the gaps between particles exist as pores, those in which the gaps between particles and the pores within the particles are shared, and those that contain foamable pores inside. It can also be roughly divided into those that have air permeability and water permeability, and those that have independent pores and are not breathable.

The shape of the above-mentioned pores is very complex and is broadly classified into open pores and closed pores, and the structure is expressed by pore volume or porosity, pore diameter and pore diameter distribution, specific surface area, etc.

Porosity is the true porosity, which is the ratio of the volume of all open and closed pores contained in a porous material to the total volume (bulk/volume) of the material, and is the true porosity. may be determined by a liquid or gas substitution method, an absorption method, etc., but as a simple method, it is defined in the JIS R2614 method for measuring the specific gravity and porosity of fireproof and insulating bricks, and is calculated as follows.

Bulk Specific Gravity True Porosity - (l - True Specific Gravity)
It is defined in the method for measuring the apparent porosity, absorption rate and specific gravity of J-K5R2205 refractory bricks, and is calculated as follows.

Note that the apparent porosity is also referred to as the effective porosity.

Saturated weight - Dry weight utnrrycv Porosity = Saturated weight - Weight in water °100
The % pore diameter is determined from the measured values of pore volume and specific surface area, and it is distributed from those close to the size of atoms and ions to the interfacial gaps of particle groups, from a few angstroms to the bottom, but in general, It is defined as the mean value of the distribution. In porous materials, the shape, size, and distribution of pores can be measured using a microscope or mercury intrusion method. In general, it is preferable to use a microscope directly in order to accurately understand the complicated shape and distribution of pores.

The BET method is often used to measure the specific surface area, which is determined using adsorption isotherms at various temperatures for various adsorbed gases.
In particular, nitrogen gas is often used.

Next, the absorption of light energy by the above-mentioned specific material, for example, a highly porous material, which is the premise of this invention, and the resulting pattern of gas pressure reduction will be explained using an inorganic highly porous material as an example.

FIG. 6 is a perspective view showing the inorganic highly porous material, and FIG. 7 is a partially enlarged sectional view of FIG. 6. In the figure, (1) indicates an inorganic highly porous material, and ■ indicates an opening leading to the surface of the inorganic material. The pore diameters of the open pores vary from a few microns to several baits.

Now, for this porous material), as shown by R in Figure 7,
When light enters the opening (2), it is reflected off the inorganic wall, undergoes multiple reflections inside the pore, and is finally absorbed 100% by the wall. In other words, the light that enters the pores is directly absorbed by the surface of the inorganic material and becomes heat within the pores.

FIG. 8 shows a curve diagram of the pressure change inside the model container when the apparent porosity of the inorganic highly porous material is changed in a model container in which the inorganic highly porous material is placed. In FIG. 8, the horizontal axis is the apparent porosity, and the vertical axis is the pressure normalized to 1 when the inner wall of the container is made of metal such as Cu, Fe, A-1-, etc.

The experimental conditions were as follows: AgW contacts were installed at a constant gap of 10 in a cubic hermetic container with -side 1ocII, and the peak 1
An arc of 0 KA sinusoidal current is generated for 3 m5 (milliseconds), and the pressure inside the container generated by the energy at this time is measured.

The inorganic highly porous material used in the above examples is porous ceramic made by molding and sintering a combustible ceramic raw material using a method such as adding a combustible or foaming agent to make it porous. 10 to 300μ, the apparent porosity of the porous material is 20% to 30%.

35%, 40%, 45%, 50%, 60%, 70%,
80%, 85%, 50mmX 50wnx 4
Various samples of wm were used and placed on the wall of the container so as to cover 50 inches of the surface area of the inner surface of the container.

Regarding the pore diameter, the issues are the average axial pore diameter, which slightly exceeds the wavelength region of the absorbed light, and the proportion of the pores to the surface, that is, the specific surface area of the pores. Further, in terms of absorption of light within the pores, deep pores are more effective, and continuous pores are preferable. The light generated from the arc A in the switch is distributed in the range of several hundred to 10,000 micrometers (1 μm), so it is suitable to have an average pore diameter that slightly exceeds this, that is, in the range of several thousand to several 1,000 μm. A highly porous material with an apparent porosity of 35% or more is suitable for absorbing the light emitted by the arc. In particular, the upper limit of the pore diameter is in the range of 1000 μm or less and the larger the specific surface area of the pores, the more effective the effect. In experiments, it was confirmed that an average pore diameter of 5 μm to 1 μm exhibits good absorption characteristics for light emitted by an arc. The material is glass, and the average pore size is 5μ, 20
It was observed that the material with μ absorbs the light emitted by the arc well.

As can be seen from Figure 8, the pores of the inorganic highly porous material absorb light energy and have the effect of reducing the pressure inside the switch. The effect was confirmed particularly when the porosity ranged from 35% or more to 85%. Further increases in porosity require corresponding increases in the thickness of the highly porous material.

However, the apparent appearance of porous materials is related to the porosity and mechanical strength; when the porosity increases, the material becomes brittle, its thermal conductivity decreases, and it is easily melted by high heat; , the effect of pressure reduction inside the switch is weak. Therefore, in practical terms, the most suitable porous material is a highly porous material with a porosity in the range of 40 to 70%.

The characteristic trends shown in FIG. 8 apply to inorganic porous materials in general, and this can be inferred from the above explanation regarding light absorption.

Some conventional switches use inorganic materials, but their purpose is primarily to protect organic containers from arc A, and their characteristics include arc resistance, service life,
Heat conduction, mechanical strength, insulation, and countermeasures against carbonization are required, and inorganic materials that meet these requirements are necessarily oriented toward densification and have different purposes, and their apparent porosity is 2
It is around 0chi.

Highly porous materials include inorganic, metallic, and organic materials, among which inorganic materials are characterized as insulators and high melting point materials. The two properties of nickel are that it is suitable as a material to be installed inside the switch container, it is an electrical insulator, so it does not have a negative effect on shutoff, and it can be used even when exposed to high temperatures. It is ideal as a pressure suppressing material because it does not melt or emit gas.

As the inorganic porous material, porous ceramics, refractories, glass, hardened cement, etc. can all be used to reduce the pressure of the gas in the switch.

Therefore, in this invention, a large number of through holes are formed in the drawing board that supports the arc extinguishing board, and by combining these with a light absorber made of the above-mentioned specific material, it is possible to effectively absorb the light energy of the arc. It is an object of the present invention to provide a switch which has excellent arc extinguishing properties and can maintain a light absorption effect for a long period of time.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 9 shows an example of a switch according to the present invention, and the same parts as in FIGS. 1 to 3 are denoted by the same reference numerals and the explanation thereof will be omitted. In the same figure, at 0 o'clock, the drawing board is holding the arc-extinguishing plate α4) as a bridge, and at the time of this side plate α, a large number of through holes) are formed. Behind the drawing board θ0, on the outer surface of the tab, a plate-shaped light absorber (as shown in FIG. 1O) is installed. This light absorber) is composed of a composite material of one or more of the aforementioned fibers, nets, and porous materials with an apparent porosity of 35% or more.

Next, the operation of the above configuration will be explained.

The opening and closing operations of the contacts (6) and (9) are as described above.

When the contacts (6) and (9) are opened, an arc (2) is generated as shown in FIGS. 11 and 12. Of the light R from this arc (to), the light emitted to the side plates (G) and (T) passes through the through hole Q5a) of each side plate (C) and enters the light absorber -. . Light R incident on the light absorber
is absorbed by the light absorber (1) due to the action of the porous material described above. Therefore, the pressure in the space P between the arc-extinguishing plates α→ shown in FIG. 11 does not increase, and therefore the arc easily enters between the arc-extinguishing plates α. Further, the arc 0 is further driven toward the arc extinguishing plate α→ side in combination with the magnetic effect or cooling effect of the arc extinguishing plate α4, and light absorption is also effectively performed. This suppresses the rise in pressure within the container, extinguishes the arc, and cuts off the current.

By the way, since the light absorber (2) receives heat from the arc (3) or absorbs light, there is a risk that the light absorber (3) will melt and be consumed if the surface temperature rises. However, since there is a side plate α0 having a through hole (J5a) in the vicinity of the light absorber, the portion of the light absorber that corresponds to the through hole a) is ) is affected by heat and light, but other parts are not affected by it, and the temperature of this part hardly rises. Therefore, the heat of the portion of the light absorber) corresponding to the through hole am> is transmitted to the other portions, thereby suppressing the temperature rise of the surface of the portion corresponding to the through hole 05a). In particular, it is possible to eliminate the risk of melting or consumption of the light absorber.

In addition, if an inorganic porous material containing magnesia or dilleconia as a main component is used as the constituent material of the light absorber (2), the surface will be crystallized without becoming gargantuan when it is directly irradiated by the arc (2). Therefore, the insulation resistance of the surface of the light absorber does not decrease during the arc generation period, and good interrupting performance can be obtained. Furthermore, if the surface of the porous material is heat-treated or if an organic material is appropriately combined with an inorganic porous material, there is no risk of interfering with the effect of lowering the internal pressure, and the powder from the light absorber due to the vibration impact of the switch can be It is also possible to effectively prevent the precipitation of.

As described above, the present invention uses a combination of an arc-extinguishing side plate having a through hole and a light absorber made of a specific material provided on the outside of the side plate to absorb the light of the arc generated when the contact is opened. Not only can it be absorbed effectively, but the action of the arc-extinguishing plate can also be fully utilized, and the internal pressure of the container can be effectively suppressed.

[Brief explanation of drawings]

Figures 1 to 3 are cross-sectional views of conventional circuit breakers.
Each indicates a different operating state. Figure 4 is an explanatory diagram showing how an arc occurs between contacts. Figure 5 is an explanatory diagram showing how an arc occurs between contacts in a container. Figure 6 is a perspective view showing an inorganic highly porous material. 7 is a partial enlarged sectional view of FIG. 6, FIG. 8 is a curve diagram showing the change in pressure inside the container with respect to the apparent porosity when an arc is generated, and FIG. 9 is an opening/closing diagram according to the present invention. FIG. 10 is a perspective view showing the main parts of the circuit breaker, and FIGS. 11 and 12 are diagrams each illustrating the operation of the circuit breaker. . (3)... Container, (4)... Fixed electrical contact, (5
)...Fixed conductor, (6)...Fixed contact, (7)...
・Movable electric contact, (8)...Movable conductor, (9)...
- Movable contact, α... arc extinguishing plate, 0 o'clock... side plate, (to)... arc, (g)... light absorber. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - (1 other person) Figure 1 2 Figure 2 Figure 3 Figure 4 Figure 6 Figure 7 Figure 8 Nyuunaiya 5L4 (7;) Figure 10

Claims (3)

[Claims] (1) at least one pair of electrical contacts configured with a conductor and a contact fixed thereto, which open and close in a container; and a pair of electrical contacts disposed in the container to open and close the electrical contacts; an arc extinguishing plate that extinguishes an arc that occurs when the arc extinguishing plate is used, and a pair of side plates that respectively support both side ends of the arc extinguishing plate, and a through hole in the both side plates that allows light from the arc to be radiated outward on both sides. and a light absorber made of a composite material of one or more of fibers, a net, and a porous material with an apparent porosity of 35% or more is provided on each outer surface of the both side plates. A switch featuring: (2) The switch according to claim 1, wherein the surface of the light absorber is hardened by heat treatment. (3). The opening/closing device according to claim 1 or 2, wherein the light absorber is formed by containing magnesia or zirconia as one of its compositions so that its surface crystallizes without vitrifying at high temperatures. vessel.