JPS5975515A - 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 8 are cross-sectional views showing conventional circuit breakers, each with a different operating state. It shows fortune-telling.

(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). (10) is a movable contact device;
(111 is a movable arm that is fixed to the crossbar (12) and is configured to be opened and closed between each pole. (13) is an arc extinguishing chamber where an arc extinguishing plate (14) is held by a side plate (15). (1G) is a toggle link mechanism, and the upper link α'
7) and the lower link (18). One end of the upper link (17) is attached to the fredl (19), and the other shaft end is attached to one end of the lower link (marked 1) with h (20) and e, respectively.
l! 1). The link below (18)
The other end is connected to the movable arm (11) of the movable contact device (101).
Connected to J. There is an adjustable operation handle (23
) is the operating spring, and the toggle link mechanism (161 shaft (21
) and the operating handle (2).

(24) and (25) are the thermal and electromagnetic trippers ti#, respectively, and when activated, the bimetallic (2)) and movable iron core, and 9) the lip bar example are rotated counterclockwise. It has become.

(support) is a latch whose one end is locked to the trip bar (2) and the other end is locked to the fredl OgI.

When the operating handle (support) is tilted to the closed position with the fredle (19) locked in the latch ■, the toggle link mechanism (16
) is expanded, the shaft (21) is locked to the fredle (19), and the movable contact (9) is joined to the fixed contact (6). This state is shown in FIG. Next, when the operating handle (27J) is tilted to the open position, the toggle link mechanism 06 is bent to separate the movable contact (9) from the fixed contact (6), and the movable arm (
lυ is locked to the fredl shaft (30). This state is shown in FIG. If an overcurrent flows through the circuit while the circuit is still in the closed state shown in FIG. When released, the fredl (1g) rotates clockwise around the fredl shaft (clockwise) and the stopper shaft (3
1). Since the connection point between the fredl (19) and the upper link αη crosses the line of action of the actuation spring (23),
The toggle link mechanism (IGI) is activated by the spring force of the operating spring.
is bent and the crossbar (12) interlocks each pole 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 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 (61, (9)
), an arc (32) is generated between the fixed and movable contacts (6) and (91), and an arc voltage is generated between the fixed and movable contacts (6) and (91). The arc current rises as the distance increases, and at the same time, the arc (32) rises further because it is attracted and elongated by the magnetic force toward the arc extinguishing plate (14).In this way, the arc current reaches the current zero point. Extinguish the arc by reaching
The shutoff is completed. However, although this injected beautiful arc energy eventually escapes completely out of the container in the form of thermal energy, it temporarily increases the temperature of the gas inside the limited container and causes an increase in the temperature of the gas. This will cause the gas pressure to rise rapidly.

As a result, there was a risk of deterioration of the insulation inside the circuit breaker, an increase in the amount of sparks emitted to the outside of the circuit breaker, and a power supply short circuit accident or destruction of the circuit breaker itself.

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

Figure 4 shows an arc A occurring between contacts (4) and (71). In the figure, T is the flow of thermal energy that is conducted from arc A to the contact and escapes, and m is the metal that escapes from the arc space. The particle energy flow, R, indicates the energy flow due to light escaping from the arc space.In Fig. 4, the energy injected into the arc A is divided into the three energy flows, T, m, H. Of this, the heat loss T to the electrode is minute, and most of the energy is carried away by m and R. Conventionally, in the mechanism of energy consumption of arc A, m in the figure is overwhelming,
The energy of R has been largely ignored, but recent research by the inventors has shown that the energy of R, that is, the consumption of energy by light, is so enormous that it reaches about 70 times the energy injected into arc A. It has now been clarified that.

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

Pw=VeI=PK0Pth+PR PK=1mv"+m @Cp-T However, PW: Instantaneous injection energy V: Arc voltage l: Current VI-I: Instantaneous electrical energy P injected into the arc
K: Instantaneous energy consumption carried away by metal particles 'my': Instantaneous energy consumption carried away when mg of metal particles fly away at speed V m-CP-T: Constant pressure specific heat CP gas (metal particle gas)
Instantaneous energy consumption carried away when escapes at temperature T Pth: Instantaneous energy consumption that escapes from the arc space to the contact by heat conduction PR Instantaneous energy consumption directly radiated from the arc according to the binary The consumption amount varies depending on the contact shape and arc length, but for an arc of 10 to 20 wm, PK =
10 to 20, P th = 5, PR = 75 to 85
It is Chi.

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 gas space Q around the arc positive column A (space Q indicated by diagonal lines in the figure) has two strong states. 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, passes through the IIM again 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 becomes zero. The path of light during this time is indicated by Ra 4Rb-+RC→Rd in the figure.

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

(1) Absorption on 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 light below 2000λ to the far infrared light above 1 μm. It spans all wavelength ranges and consists of continuous spectra and line spectra. Even if the surface of a typical container is black, it only has the ability to absorb light in the range of about 4000λ to 5500λ, and in other ranges,
Only a portion of it is absorbed, and most of it is reflected.

However, absorption occurs in the arc space and surrounding high-temperature gas space.

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=Ae-n-L I in
-(1) ■a: Absorbed energy by gas A: Absorption probability Iin: Irradiated light energy n: Particle density L: Optical path length through which light passes. However, equation (1) indicates the amount of absorbed energy with respect to the latent wavelength λ . Ae is the absorption probability for a specific wavelength λ, and is a function of the wavelength λ, gas temperature, and particle type.

Regarding equation (1), according to the teachings of shield mechanics, the absorption coefficient Ae is largest for a gas in the same state as the light source gas that emits light (that is, the particle species M1 temperature is the same) in 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 absorbed energy of light 441 I a
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. The amount of light energy used 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 times the energy injected into the arc. A fiber net that effectively absorbs the light emitted by the arc and one of the highly porous materials with an apparent porosity of 85% or more are placed at specific positions that receive the light energy of the arc.
By arranging seeds or composite materials of two or more kinds,
It absorbs a large amount of light inside the container, lowering the temperature of the gas space and thereby lowering the pressure.

The above-mentioned fibers are selected from inorganic materials, composite materials, woven materials, non-woven fabrics, etc., but since they will be installed in a space exposed to high-temperature arcs, all materials must have thermal strength. There is.

Further, as the net, in addition to inorganic materials and composite materials, a layered fine wire net or a knitted wire can also be selected. In the case of this net as well, it is necessary to select one that has thermal strength.

Among the above-mentioned fiber and mesh materials, inorganic materials such as ceramic, carbon, and asbestos are suitable.

Porous materials are generally materials with a large number of pores within a solid structure, and exist in a wide range of inorganic 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.

Furthermore, this classification can be divided into 44 types in which the gaps between particles exist as pores, those that share the pores between the particles and the pores within the particles, and those that contain foamable pores inside. be able to. 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.

The true porosity 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, that is, the true porosity is expressed as a percentage. It may be determined by a liquid or gas substitution method, an absorption method, etc., but as a simple method, it is defined in JISR2614 method for measuring specific gravity and porosity of fireproof and insulating bricks, and 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 the apparent porosity of JISR 2205 firebrick,
As defined in the method for measuring absorption rate and specific gravity, it is calculated as follows.

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

Pore diameter can be determined from the measured values of pore volume and specific surface area, and ranges from a few λ (angstroms) to several angstroms, ranging from those close to the size of atoms and ions to the interfacial gaps between particles. 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.

-11 In order to accurately understand the complicated shape and distribution of pores, it is preferable to use a microscope directly.

The BET method is often used to measure the specific surface area, which is determined using the adsorption contour lines at each temperature for various adsorbed gases.
In particular, nitrous gas is often used.

Next, MIW, which is the premise of the present invention, is the absorption of light energy by the above-mentioned specific material, such as a highly porous material, and the resulting reduction in gas pressure, 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 same figure, (33)
(34) indicates an inorganic highly porous material, and (34) indicates an opening leading to the surface of the inorganic material. The pore diameters of the open pores show a wide range of sizes, from several microns to several liters.

Now, when light enters the porous material (33) as shown by R in Figure 7, when the light enters the aperture,
The light is reflected off the inorganic wall, undergoes multiple reflections inside the pores, and is finally absorbed 100 times by the wall. That is, the light incident on the opening (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 a real 1 parsimony condition, −side 1Oc
An AgW contact is installed with a constant gap of 10 mm in a cubic sealed container of rn, and an arc of sine wave current with a peak of 10 KA is generated for 8 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 range is 10-800 μm, and the apparent porosity of the porous moon is 20 cm.

80chi, 85%, 40chi, 45%, 50%, 60%, 7
Use various samples of 0%, 80 inch, and 85 inch, 50 x 50 x 4 fins, and place them on the wall of the container.
It was designed to cover 50% 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 ψ 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 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 (1/4 m), it is suitable to have an average pore diameter that slightly exceeds this, that is, from several thousand λ to several 1,000 μm. A highly porous material in which the area of pores occupying the surface has an apparent porosity of 85% or more is suitable for absorbing the light emitted by the arc. In particular, the larger the specific surface area of pores with an upper limit of pore diameter of 1000 μm or less, the more effective the effect. In experiments, it was confirmed that an average pore diameter of 5 μm to lsm 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 μ material 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. However, this becomes especially noticeable when the porosity is 85% or higher, and the effect was confirmed in the range up to 85%. Further increases in porosity must be accommodated by further increasing the thickness of the highly porous material.

However, the appearance of porous materials is related to the porosity and mechanical strength.If the porosity becomes large, it becomes brittle, has low thermal conductivity, and is easily melted by high heat, and if the porosity is small, the switch The effect of internal decompression is weak. Therefore, in practical terms, it is best to use a highly porous material with an apparent porosity in the range of 40 to 70 inches.

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. Conductivity, 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 It is around 20 inches.

Highly porous materials include inorganic and organic materials, and inorganic materials are characterized by their insulating properties and high melting points. These two properties make it a good material to install inside the switch container.Since it is an electrical insulator, it does not have a negative effect on shutoff, and even if exposed to high temperatures, it will not melt. Since it does not emit gas, it is ideal as a pressure suppressing material.

Examples of the inorganic porous material include porous ceramics, refractories, glass, hardened cement, etc.) Any of them can be used to reduce the pressure of the gas in the switch.

Therefore, the present invention provides a conductor with a pressure reflector that surrounds the outer periphery of the contact point of an electric contact, and furthermore, the present invention provides a pressure reflector that surrounds the outer periphery of the contact point of an electric contact, and furthermore, a pressure reflector is provided on the conductor, and the pressure reflector is further provided with a pressure reflector that is selected from among the above-mentioned specific materials that absorb light energy. This relates to a switch that can improve current limiting performance and suppress internal pressure by providing an absorber in a space that receives optical energy.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 9 shows an example of a circuit breaker to which the switch according to the present invention is applied. In the same figure, (101),
(102) is a pressure reflector υ and a conductor (5).

The outer peripheries of the fixed contact (6) and the movable contact (9) are made of a high resistance material having a higher resistivity than the material forming the contact (6), as shown in FIGS. 10 and 11, respectively. A fixed conductor (5) and a movable conductor (
8) is fixed. These pressure reflectors (101),
The high-resistance materials constituting (102) include organic or inorganic insulators or high-resistance metals such as nickel, iron, copper-nickel, copper-manganese, copper-manganin, iron-carbon, iron-nickel, and iron-chromium.

The pressure reflectors (101) and (102) are made by coating the υ conductors (5) and (8) with the above-mentioned high-resistance material, such as ceramic, by means of plasma jet spraying, or by fabricating the above-mentioned high-resistance material. The above conductor (
51, (can be easily formed by fixing it to 81. According to the above-mentioned covering means, it is not only easy to form, but also inexpensive, and the increase in the amount of i can be suppressed, especially on the movable contact (7) side. This has the advantage that the moment of inertia is small and the opening speed of the movable contactor (7) is large, thus making it possible to increase the arc voltage.

(108) is a light absorber selected from organic and inorganic systems, and has fibers, a mesh, and an apparent porosity of 85.
% or more of porous materials, for example, the apparent porous material is composed of a porous material with a porosity of 85 cm or more, and the material that occurs between the above contact points i6) and (9) The part that receives the light of Arc Co., Ltd., for example, is located on both sides of the contact points (61 and (91) as shown in Fig. Explanation will be omitted.

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

An arc (
32) is the same as the conventional one, but a pressure reflector (101), (
102), the arc (32) is squeezed into a narrow space.

As a result, the cross-sectional area of the arc (32) is equal to the pressure reflector (10
1) and (102) are extremely small compared to the conventional one without (102). Therefore, the arc voltage increases greatly and the current limiting performance is significantly improved.

By the way, due to the above, the magnitude of the flowing current decreases, but as the arc voltage increases, the instantaneous electrical energy (product of current and arc voltage) injected into the circuit increases, causing the pressure inside the container to increase rapidly. This may lead to damage to the circuit breaker body or an increase in the amount of sparks emitted.

However, in configuration 1, since the light absorber (103) is installed at the part that receives the light from the arc country, the light energy of the north arc f'12+ is absorbed by the above-mentioned light absorption effect. The arc gas pressure can be suppressed and the internal pressure can be lowered, and the pressure reflector (101),
(102) can fully fulfill its duties without hindrance to its use.

FIG. 12 shows a deformed structure of the pressure reflector, and the pressure reflector (104) in this example has a fixed contact (6) in the direction from the tip (6a) to the contact (6), For example, the front side in the arc traveling direction, that is, the arc extinguishing plate (14) tl
A grooved arc running path (105) is formed toward the llll. According to this configuration, the legs of the arc (321) run on the arc travel path (105) and face toward the arc extinguishing plate (141), making it easier to touch the arc extinguishing plate (14), and thereby making it possible to break the small current area. Improved performance.

By the way, if an inorganic porous material containing magnesia or zirconia as a main component is used as the material of the light absorber (10B), its surface will crystallize without becoming vitrified when directly irradiated with the arc (32). Therefore, it is possible to obtain good interrupting performance without reducing the insulation resistance of the surface during the generation period of the arc ((2).Furthermore, the surface of the light absorber (103) is heat-treated and inorganic porous. If it is composed of a material suitably combined with an organic material, it will effectively prevent the precipitation of powder from the light absorber (103) due to vibration impact without interfering with the effect of lowering the internal pressure of the container (3). You can also.

As described above, this invention improves current-limiting properties and suppresses internal pressure by combining a pressure reflector provided on an electrical contact and a light absorber made of a specific material selected from inorganic and organic materials. It is possible to provide a switch that can achieve the following.

[Brief explanation of the drawing]

1-3 are cross-sectional views of conventional circuit breakers, each showing different operating conditions. Figure 4 is an explanatory diagram showing how an arc is generated between contacts, Figure 5 is an explanatory diagram showing how an arc is generated between contacts in a container, and Figure 6 is a non-geometric highly porous material. FIG. 7 is a partially enlarged sectional view of FIG. 6, FIG. 8 is a curve diagram showing changes in pressure inside the container with respect to apparent porosity when an arc is generated, and FIG.
The figure is a front cross-sectional view showing an example of a circuit breaker to which the switch according to the present invention is applied, Figure '@10 is a perspective view showing the main parts of the circuit breaker, and Figure @l1 is a pressure reflector attached and fixed. A perspective view of the electric contact; FIG. 12 is a perspective view of the fixed electric contact showing a modified structure of the pressure reflector. (3)... Container, (4)... Fixed electrical contact, (5
)...Fixed conductor, (6)...Fixed contact, (7)...
・Movable core 1 melter, (8)...Movable conductor, (9)・
・・Movable contacts, (101), (102), (104)・
... Pressure reflector, (108) ... Light absorber, (105
)...Arc running path. Note that the same reference numerals in the figures indicate the same or corresponding parts. Fig. 81 Fig. 9 Fig. 2 Condolence 3 (Me1 2 264 Fig. Poor) Fig. 7 Fig. 8 Danger f') Moxibustion 7. L prison (%1 Figure 9 2 Figure 10 Figure 11 LJI '#N2 Figure

Claims (4)

[Claims] (1) at least one pair of electrical contacts, which are composed of a conductor and a contact fixed thereto, and which operate to open and close within the container, and the conductor is also composed of a high-resistance material with high resistivity; and a pressure reflector disposed on the conductor so as to surround the outer periphery of the contact, and a light absorber disposed in a space that receives light energy from an arc generated when the electrical contact is opened. and the light absorber is selected from organic and inorganic materials, and one or two of fibers, nets, and porous materials with an apparent porosity of 85 cm or more.
A switch constructed from a composite material of more than 100% of species. (2) a pressure reflector of at least one electrical contact;
2. The switch according to claim 1, further comprising an arc travel path extending forward in the direction of arc movement from the contact point and having higher conductivity than the pressure reflector. (3) The switch according to claim 1 or 2, wherein the surface of the light absorber is hardened by heat treatment. (4) 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. The switch according to item 1, item 2, or item 8.