JPS5979933A - 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" as used in the present invention particularly refers to a device that generates an arc within a container, usually a small container, such as a circuit switch, disconnector, current limiter, or electromagnetic switch.

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

Figures 1 to 8 are cross-sectional views showing conventional circuit breakers.
Each shows a different operating state.

``(1) is a cover, (2) is a paste, and the cover (1) and paste (2) constitute a container (3).(4) is a fixed liquid M, and a fixed conductor (5) Fixed contact (6) at one end of
The other end is a terminal portion to be connected to an external conductor (not shown). (7) is a movable contact, which is attached to one end of the movable conductor (8) and has a movable contact (
9). (10) is a movable contact device, (11
) is a movable arm, which is fixed to the crossbar and is configured to open and close between each pole. The side plate that supported the (1
ω and Yoshi are formed. (16) is a toggle link mechanism, consisting of the upper link (1η) and the lower link (1 mark). Axis (4), (2
B is connected many times. The other end of the lower link is connected to the movable arm (11J) of the movable contact device. il shaft (211) and the operating handle (2).

(to) and (2) are thermal and electromagnetic trip mechanisms, respectively, which rotate the i-lip bar (4) counterclockwise using a bimetal (support) and a movable iron core (5), respectively, when activated. ing. (2) has two ends, one end of which is locked with the tripper [K, and the other end of which is locked with the fredle (1ω).

If the operating handle (2) is tilted to the closing position with the Freddle α Yu locked in the 2nd position, the toggle link mechanism (l
e is extended, the shaft Qυ is slightly locked with the handle U, and the movable contact (9) is brought into contact with the fixed contact (6). This state is gt
It is a diagram. Next, when the operation handle (2) is tilted to the open position, the toggle link machine +/II (161) is bent to open the movable contact (9) from the fixed contact (6), and the movable arm (1
11 is locked to the fredl shaft (■). This state is shown in FIG.

Furthermore, if an overcurrent flows through the circuit in the closed state shown in FIG. , the fredle (19) rotates in the direction of the hour hand around the fredle shaft (A) and is locked to the stopper shaft (311. At this time, the connection point between the fredle (19) and the upper link (17) ), the toggle link mechanism Oe is activated by the spring force of the operating spring (23).
When the crossbar is bent, each pole interlocks and automatically shuts off. This state is shown in FIG.

Next, the behavior of the arc generated when the circuit breaker cuts off 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 source 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 (Fig. 8) A occurs between the fixed and movable contacts +61 and +91, and an arc voltage is generated between the fixed and movable contacts +61 and +91. This arc voltage is caused by the voltage of the movable contact (9) from the fixed contact (6). As the separation distance increases, the arc current rises, and at the same time, the arc A is drawn toward the arc-extinguishing plate αa by the magnetic force and expands, causing the trap to rise further.In this way, the arc current reaches the current zero point. The arc is extinguished and the interruption is completed.However, this injected beautiful arc energy eventually escapes in the form of thermal energy and completely escapes from the container, but only temporarily. This will cause the temperature of the gas inside the container to rise, which in turn will cause the gas pressure to rise sharply.This will cause the insulation inside the circuit breaker to deteriorate and the amount of sparks emitted to the outside of the circuit breaker to increase, resulting in a power supply short circuit. There was a risk of an accident or destruction of the circuit breaker itself.

Next, we will discuss the energy consumption mechanism of the arc, which is 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 metal particles escaping from the arc space, and R indicates the flow of energy due to light escaping from the arc space. In Fig. 4, the energy injected by the arc AK flows through the above three energies f), T, m, RI
c, it is mostly consumed. Of this, the heat escape T to the contact 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 overwhelmingly dominant, and the energy of R was almost ignored, but recent research by the inventors and others shows that the energy of R is In other words, it has been revealed that the energy consumption by light is so great that it reaches about 70% of the energy injected by arc AK.

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

Pw=V@I=PK+Pth0PR PK=4mV"+m-CP*'I'However, Pw: Instantaneous injection energy V: Arc voltage I: Current v Bow: Instantaneous electrical energy PK injected into the arc
: Instantaneous energy consumption carried away by metal particles 2mV" : Instantaneous energy consumption carried away when metal particles rng fly away at speed V m*cP*TH Gas with constant pressure specific heat CP (metal particle gas)
Instantaneous energy consumption that is carried away when it escapes at temperature TK Pth: Instantaneous energy consumption that escapes from the arc space to the contact by heat conduction PR: Instantaneous energy consumption that is radiated directly from the arc by light The consumption varies depending on the contact shape and arc length, but for an arc of 10 to 20 m, PK = 1.
0-20%, Pth=5%, PR-75-85q6.

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 from arc A is emitted from arc positive column A,
The light is irradiated and reflected by the wall of the container (3). The reflected light is scattered and passes through the high temperature space filled with residual disease particles again.
This process of illuminating the wall surface is repeated until the amount of light reaches zero. The path of light during this time is shown as Ra-+Rb→RC-+Rd in the figure.

In the above process, the consumption of light emitted from arc A is 02 points.

(1) Absorption on the wall (2) Absorption by the arc space and surrounding (high temperature) gas space, that is, absorption by the gas space.Also, the light emitted from arc A ranges from the far ultraviolet below 2000 Å to the far infrared above 71 μm. It consists of a continuous spectrum and a line spectrum spanning all wavelength ranges.

Even if the surface of a typical container wall is black, it is only within the range of about 4000λ to 5500λ.
It only has the ability to absorb light; in other areas, it only partially absorbs and reflects most of it.

However, absorption in the arc space and surrounding high temperature gas space is as follows.

When a gas space having a uniform composition and temperature over its length is irradiated with light of wavelength λ, the amount of light absorbed by the gas space can be calculated as follows.

I a = A e ・n @L I i n
・--(1)■R: Absorption energy by gas Ae: Absorption probability Iin: Irradiated light energy n: Particle density L: Optical path length through which light passes. However, equation (1) is the amount of absorbed energy for a specific wavelength λ shows. A is the absorption probability for a specific wavelength λ and is a function of wavelength λ, gas temperature, and particle type.

Regarding equation (1), according to the teachings of quantum mechanics, the absorption coefficient A is determined by dividing both the continuous and line spectra by the gas that is in the same state as the light source gas that emits light (that is, the type of particles and temperature are the same). It will have a large 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 amount of absorbed energy Ia of light is proportional to the optical path length. As shown in Figure 5, when the light from the arc space is reflected by the wall surface, the value in equation (1) increases by the number of reflections, and the light is absorbed in the high temperature part of the arc space. This results in an increase in the amount of light energy used.

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 85 cm or more that effectively absorb the light emitted by the arc are placed at specific locations that receive the light energy of the arc.
By selectively arranging a species or a composite of two or more species, a large amount of light within the container is absorbed to lower the temperature of the gas space, thereby lowering the pressure.

In general, the above-mentioned fibers are selected from inorganic, organic, composite materials of inorganic and organic, metals, woven materials, non-woven fabrics, etc.; On top of that, it needs to have thermal strength.

In addition, the mesh may be made of inorganic, organic, inorganic/organic composite materials, metal, etc., as well as multiple layers of thin wire mesh or wire mesh. be.

This net also needs to have thermal strength.

Among the materials for the fibers and nets mentioned above, inorganic materials such as ceramic, carbon, and asbestos are suitable;
E, Cu is most suitable, but plating of Zn, Ni, etc. is 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 is made by sintering and solidifying solid particles at one point, and the other is made of 1×31 pores and the partition walls forming the pores are made of solid material. Note that in this invention, the raw material 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 share the pores within the particles, and those in which the pores are contained within the foamable pores. It can also be broadly classified 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 roughly classified into open pores and closed pores, and the structure is expressed by pore volume, porosity, pore diameter, pore diameter distribution, specific surface area, etc.

Porosity is the ratio of the volume of all open and closed pores contained in a porous material to the total volume of the material (the ratio of pores to the bulk volume, that is, expressed as a percentage, is the true porosity1, and the measurement method is Although it is based on the liquid or gas displacement method and absorption method, it is recommended that the simple method is defined in JISR 2614 method for measuring specific gravity and porosity of fireproof and insulating bricks.
aF is calculated as follows.

In addition, the ratio of the open pore volume to the total volume (bulk volume)' of the material, that is, the apparent porosity expressed as a percentage, is used to measure the apparent γ porosity, absorption rate, and specific gravity of JISR 2205 refractory bricks. As defined in the method,
It is calculated as follows.

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

The pore diameter can be determined from the measured values of the pore volume and specific surface area, but it is estimated that the force is distributed in the range of 1 to 1 from those close to the size of atoms and ions to the interfacial gaps between particles. t1 is generally defined as the mean value of the distribution. In the case of carbonaceous materials, it is possible to measure the shape, size, and distribution of pores using a microscope or mercury intrusion method. In order to know the power of using a microscope, it is preferable.

To measure the specific surface area, the BET method is often used, which is determined using adsorption isotherms of various adsorbed gases at each temperature per year, and nitrogen gas is especially used).

Next, the pattern of absorption of light energy by a 11゛♀ material and the resulting drop in gas pressure, which is the premise of this invention, will be explained in detail.

FIG. 6 is an ffI view showing the inorganic highly porous material, and FIG. 7 is a partially enlarged sectional view of FIG. 6. In 1 Tsukasa 1 Kyou (
Material) is an inorganic highly porous material, and 341 indicates a large number of holes on the surface.The fine L diameter of the hole (34) varies in size from a few microns to a few holes. This shows a distribution.

Now, as shown by R in FIG. 7, when light enters this porous material (to) and enters the opening (34),
Light hits the inorganic wall, is reflected, undergoes multiple reflections inside the pores, and is finally absorbed by the wall 100 times. That is, the light incident on the aperture (34) is directly absorbed by the surface of the inorganic material and becomes heat within the pore.

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, or AI. As for the experimental conditions, −side 10
An AgW contact is installed with a constant gap of 10 m in a cubic hermetic container of 10 m, and an arc of a sinusoidal current with a peak of 10 KA is generated.
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 cordierite ceramic raw material by adding a combustible or foaming agent, etc. to make it porous, and the average pore size is The apparent porosity of the range lO~800μ porous material is 20%, 80%, 85%, 40%, 45%
, 50cm, 60cm, 70%, 80cm, 85cm,
Using various samples of 50 x 50 m + x 4 + m,
This was 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 pore diameter, which slightly exceeds the wavelength range of the absorbed light, and the ratio 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. Since the light generated from the arc A in the switch is distributed over several hundred λ to 10,000 λ (1 μm), it is suitable to have an average pore diameter that slightly exceeds this range, that is, from several thousand λ to several 1000/jm. A highly porous material in which the area of pores occupying the surface has an apparent porosity of 85 cm or more is suitable for absorbing the light emitted by the arc A. 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 it is. In experiments, it was confirmed that an average pore diameter of 6 μm to 1 m showed good absorption characteristics for light emitted by an arc. In addition, the material is glass and the average pore diameter is 5μ, 2
Good light absorption was observed for the light emitted by the arc at 0μ.

As can be seen from the characteristic curve a in Figure 8, the pores of the inorganic highly porous material absorb light energy and have the effect of reducing the pressure inside the switch. It becomes larger as the porosity increases, and becomes particularly noticeable when the porosity is 85% or more, and the effect was confirmed in the range up to 85%.

Further increases in porosity require corresponding increases in the thickness of the highly porous material.

However, the apparent relationship between the porosity and mechanical strength of porous materials is such that as the porosity increases, the material becomes brittle and its thermal conductivity decreases, making it more likely to melt due to high heat. The effect of reducing pressure inside the switch is weak. Therefore, in practical terms, a highly porous material with an apparent porosity in the range of 40 to 7 (l) is optimal.

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 the main purpose of their use is to protect organic containers from arcs, and their characteristics include arc resistance, service life, heat conduction, and mechanical properties. Physical strength, insulation properties, and countermeasures against carbonization are required.
Inorganic materials that meet these requirements are necessarily densified and have different purposes, and their apparent porosity is 20%.
It is before and after.

Highly porous materials include inorganic, metallic, and organic materials, among which inorganic materials are characterized as insulators and high melting point paulownia materials. These two properties make it ideal as a material to be installed inside the switch container.Since it is an electrical insulator, there is little adverse effect on shutoff (a), and it does not melt even when exposed to high temperatures. Pressure-suppressing material binding-C is optimal because it is difficult to release gas.

Porous inorganic materials include porous ceramics, refractories, glass, hardened cement, and the like, and any of them can be used to reduce the pressure of gas in the switch.

Next, embodiments of the present invention will be described based on the drawings.

FIG. 9 is a perspective view showing essential parts of a circuit breaker according to a first embodiment of the invention. In this figure, (4) is a fixed contact, and the fixed contact (6) is located at the top of the fixed conductor (5).
) becomes stuck. (7) is a movable bridge (illζ) in which a movable contact (9) that contacts and separates from the fixed contact (6) is fixed to the lower end of a movable conductor (8). (g) and t(5) are This is a slit arc-extinguishing board made of an insulating board, and the fibers, net, and appearance described above are composed of one or more composite materials of porous materials with a porosity of 85% or more. Arc plate (to), ((5) shows the arc A between the movable contact (9) and the fixed contact (6), which occurs when the movable contact (7) is separated from the fixed contact (4), on both sides. The movable contacts (7) are arranged parallel to each other so as to be sandwiched therebetween, and a necessary minimum gap g that does not impede the opening/closing operation of the movable contactor (7) is formed between the opposing surfaces.

Note that the other configurations are the same as those of the conventional one, so a description thereof will be omitted.

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

From the power supply, connect the fixed conductor (5), fixed contact (6), and movable contact (
9) When the electric power being supplied to the load via the movable conductor (8) is cut off by opening the movable contactor (7) from the fixed contactor (4), an arc occurs between the contacts (61 and (91). A is generated, but since this arc is sandwiched between the slit arc extinguishing plates C351, (to), the arc cross-sectional area perpendicular to the arc current direction is prevented from increasing, and the arc resistance between the contacts increases rapidly. However, the arc is quickly erased.

By the way, as mentioned above, the slit arc-extinguishing plates ('1) are installed facing each other with a slit g that is just narrow enough not to obstruct the movement of the movable contact (7), so they do not have a dense structure like the conventional one. In the slit arc extinguishing plate made of insulating members, the pressure generated by the arc energy is enormous, and the force d - (1),
However, in this invention, the slit arc-extinguishing plate (35) + ("' means fiber, net, and a porous material with an apparent porosity of 85 cm or more. Because it is composed of compound interest of one or more of these,
The slit arc extinguishing plates f35) and (35) absorb the energy of the light emitted by the arc A, which is the source of pressure generation, and the internal pressure of the container at the time of shutoff is significantly reduced. As a result, the mold container does not break when it is shut off, which was a problem in the past, and the mechanical strength of the container (3), which consists of the cover (1) and the base (2), can be reduced. (1) A cover that greatly reduces the amount of mold material forming the base (2) (11) A cover that uses a cheaper grade material with low mechanical strength as the material for the base (2). (1), the cost of the base (2) can be reduced.Furthermore, due to the decrease in the internal pressure of the container, the amount of sparks emitted from the container (3) at the time of current cut-off is reduced. Secondary disasters such as short-circuit accidents on the power supply side are prevented, and safety and reliability are improved.

In addition, the arc cross-sectional area is reduced because the slit arc-extinguishing plates (35) and +35) are placed opposite each other with a slit g that is not obstructing the movement of the movable contact (7). This increases the arc resistance and provides a high current limiting effect.

Furthermore, if an inorganic porous material containing zirconia or magnesia as the main component is used as the material for the slit arc-extinguishing plate, even if the surface of the slit arc-extinguishing plate becomes hot due to direct exposure to the arc, Since it is crystallized without vitrification, the megohm on the surface of the slit arc extinguishing plate does not decrease during the arcing period, and good interrupting performance can be obtained. Furthermore, by heat-treating the surface of a slit arc-extinguishing plate made of an inorganic porous material, or by appropriately compounding an inorganic porous material with an organic material, it is possible to reduce the vibration impact of the switch without significantly hindering the internal pressure reduction effect. It is possible to prevent the precipitation of powder from the slit arc-extinguishing plate and improve reliability.

FIG. 1O is a perspective view of a main part according to a second embodiment of the present invention. In this example, the two left and right slit arc-extinguishing plates (to),
The part facing the vicinity of the contact point (to) is made of a dense insulating plate (85a) with an apparent porosity of 85 cm or less, as in the conventional case, and the other parts are made of fibers as in the first embodiment. , the net and appearance are made of porous materials with a porosity of 85% or more.
It is composed of an insulating plate (85b) as a light absorber made of a seed or a composite material of two or more types. Of course, a slit arc extinguishing plate! 35) 4 (35) are facing each other with a narrow gap g that is as small as possible without inhibiting the movement of the movable contact (7). Therefore, in the second embodiment as well, substantially the same effects as in the first embodiment can be obtained by using the slit g and the insulating plates (85b) and (85b) as light absorbers.

As can be seen from the above description, according to the switch of the present invention, the gap arc-extinguishing plates made of two insulating plates are opposed to each other while maintaining a gap that does not inhibit the opening/closing operation of the electric contact, and The other parts of the slit arc-extinguishing plate, excluding at least the part facing the vicinity of the contact point, are composed of fibers, nets, and a composite material of one or more of porous materials with an apparent porosity of 85 cm or more. As a result, the internal pressure can be effectively lowered, safety and reliability can be improved, costs can be reduced, and a high current limiting effect can be obtained.

[Brief explanation of drawings]

Figures 1 to 8 are cross-sectional views of conventional circuit breakers, Figure 4 is an explanatory diagram showing how an arc occurs between contacts, and Figure 5 is a cross-sectional view of a conventional circuit breaker.
The figure is an explanatory diagram showing how an arc is generated between the contacts in the container, Figure 6 is a perspective view showing the inorganic highly porous material, Figure 7 is a partially enlarged sectional view of Figure 6, and Figure 8 is an arc FIG. 9 is a perspective view of the main part showing the first practical example of the present invention, and FIG. 10 is a curve diagram showing the change in pressure inside the container with respect to the apparent porosity when generating It is a perspective view of the important part shown. (3)...Container, +4), +7)...Electric contact, +5), +8)...Conductor, (61, <91・
...Contact, (351, pa, slit arc extinguishing plate, g...slit,
A... Arc. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Shin Kuzuno (1 other person)

Claims (3)

[Claims] (1) At least one pair of electric contacts, which are composed of a conductor and a contact fixed to the conductor, and which perform opening and closing operations within the container, and parallel to each other so as to sandwich the arc generated when the electric contacts open and close from both sides. and a slit arc-extinguishing plate consisting of two insulating plates facing each other and forming a slit between their opposing surfaces that does not inhibit the opening/closing operation of the electrical contact, and the slit arc-extinguishing plate The other part, excluding at least the part facing the vicinity of the contact point, is comprised of one or more composite materials of fibers, nets, and porous materials with an apparent porosity of 85 cm or more. A switch with (2) The switch according to claim 1, wherein the surface of the slit arc-extinguishing plate is hardened by heat treatment. (3) The switch according to claim 1 or 2, wherein the slit arc-extinguishing plate is formed mainly of magnesia or zirconia.