JPS58181243A - 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 the pressure within the tray of a switch. Note that the term "switch switch" as used in the present invention particularly refers to a circuit interrupter, 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 pace, and the cover (1) and base (2) constitute a container (3). (4) is a fixed contact, which has a fixed conductor (5), has a fixed contact (6) at one end, and has a terminal part at the other end to be connected to an external conductor (not shown). It has become. (7) is a movable contact, which has a movable contact (9) at one end of its movable conductor (8) opposite to the fixed contact (6). ◇ The movable contact device is fixed to the crossbar (c) with the movable arm αη, and is configured to be opened and closed when each pole is spaced. (to) is the arc extinguishing chamber, and the arc extinguishing plate α is held by the side plate).

(G) is a toggle link mechanism, which is composed of an upper link αη and a lower link. One end of the upper link side is Credo A
/an, and the other end is connected to one end of the lower link (E) by shafts (4), Q]), respectively. The other end of the lower link is connected to the movable arm α of the movable contact device a0. 2) is an adjustable operation handle, (c)
is an operating spring, which is stretched between the shaft 31) of the toggle link mechanism α and the operating handle). (Foundation) and Ni) are thermal and electromagnetic tripping mechanisms, respectively, and when activated, they are bimetallic) and movable iron core (Foundation), respectively.
(on the retrieval bar) in a counterclockwise direction. 2) is a latch whose one end is locked to the trip bar (4) and the other end is locked to the Freddle Qllll.

When the operating hand /I/ (A) is turned to the closed position with the Freddle 0 grip (on the latch), the toggle link mechanism (to) will extend, the shaft Qυ will be locked on the Fledle 0 grip, and the movable contact ( 9) is joined to the fixed contact (6). This state is the first
It is a diagram. Then, when the operating handle (on the operating handle) is tilted to the open position, the F glu link mechanism α is bent to open the movable contact (9) from the fixed contact (6), and the movable arm αD is locked to the fredle shaft). be done. This state is shown in FIG. Additionally, if an overcurrent flows through the circuit in the closed state shown in Figure 1, the thermal tripping mechanism or electromagnetic tripping mechanism will operate and release the engagement between the fredle Oe and the latch (E). , Credo yv (
19) rotates and is locked to the nut-tube shaft 0◇.

Since the connecting point between the fredle 01 and the upper link αη crosses the line of action of the above-mentioned operating spring (c), the toggle link mechanism α is bent by the spring force of the operating spring (c), causing the crossbar (6) to bend.
Automatic shutoff is performed in conjunction with each pole. 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 is attracted and elongated by the magnetic force in the direction of the arc-extinguishing plate α→, so it rises further. In this way, the arc current reaches a current zero point, the arc is extinguished, and the interruption 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.

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, which may lead to power supply short-circuit accidents 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.

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 into arc A is almost consumed by the three energy flows T, m, and H mentioned above. Of this, 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 energies of sb and R were almost ignored, but recent research by the inventors has shown that the energy of R is , that is, the energy consumption by light is approximately 70% of the energy injected into arc A.
It has come to light that she is so good at art that she even reaches the age of 100.

That is, the consumption of energy injected into arc A can be analyzed as follows.

Present = V・Work= Px + Pth + PR However, Pw: Instantaneous injection energy ■: Arc voltage work: Current ■・Work: Instantaneous electrical energy injected into the arc PK:
Instantaneous energy consumption m-Cpl: Instantaneous energy consumption taken away by metal particles when gas with constant pressure specific heat Cp (metal particle gas) escapes at temperature T Pth: From arc space to contact Instantaneous energy consumption PR: Instantaneous energy consumption radiated directly from the arc by light or heat The above consumption varies depending on the contact shape and arc length, but for an arc of 10 to 20 ff. For each, pr
= 10-20%, Pth = 5%, PR = 7
It is 5 to 85 inches.

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, and is irradiated onto the wall of the container (3) and 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 −+ Rb −+ Rc −+ Rd.

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

α) 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 light emitted from the arc, from the far ultraviolet light below 2000λ to the far infrared light above 1 μm. wavelength range)
, consisting of a continuous spectrum and a line spectrum p. Even if the surface of a typical container wall is black, it has a 400%
It has the ability to absorb light only in the range of about 0.01 to 5,500 people, and in other ranges, it only absorbs a part of the light 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 length L and having a uniform composition and temperature is irradiated with light of wavelengths, the amount of light absorbed by the gas space can be calculated as follows.

Ia = Ae −n −LIin −=
(1) Equation a: Absorbed energy by gas Ae: Absorption probability Equation: Irradiated light energy n: Particle density L: Optical path length through which light passes. However, equation (1) indicates the amount of absorbed energy for a specific wavelength λ. . Ae is the absorption probability for a specific wavelength,
It is a function of wavelength, gas temperature, and particle type.

Regarding equation (1), according to the teachings of quantum mechanics, the absorption coefficient Ae has the largest value for a gas that is 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. will have the following. That is, the light emitted from the arc space is absorbed most by the arc space and the surrounding gas space.

In equation (1), the amount of absorbed energy of light 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, L in equation (1) increases by the number of reflectors, and 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 times the energy injected into the arc. By placing a porous material that effectively absorbs the light emitted by the arc at a specific location that receives the light energy of the arc, it absorbs a large amount of light inside the container and lowers the temperature of the gas space, thereby reducing the pressure. This reduces the

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 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 and the pores within the particles are shared, and those that are foamable and contain 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 ratio of the volume of all open and closed pores contained in a porous material to the total volume of the material (bulk volume), that is, the true porosity is expressed as a percentage, and the measurement method is is determined by a liquid or gas substitution method, an absorption method, etc., but as a simple method, it is calculated as defined in JISR2614 method for measuring specific gravity and porosity of fireproof and insulating bricks.

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 J-Ko SR2205 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 is determined from the measured values of pore volume and specific surface area, and ranges from a few angstroms to several nanometers, ranging from those close to the size of atoms and ions to the rwJ gap at the interface 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. 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 by using adsorption crosstalk at each temperature of various adsorbed gases.
In particular, nitrogen gas is often used.

Next, we will explain the absorption of light energy by a specific material and the resulting drop in gas pressure, which is the premise of this invention.
This 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, (to) shows the highly porous inorganic material, and (b) shows the openings leading to the surface of the inorganic material. The pore diameter of the open pores is from several μ to several mm.
This shows a distribution of various sizes.

Now, as shown by R in Figure 7, when light enters this porous material (2), when it enters the opening (b), the light is reflected off the wall of the inorganic material, and then The light is reflected multiple times inside the pores and is finally absorbed 100% by the walls. In other words, the light incident on the opening (2) 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, A1, etc.

The experimental conditions were as follows: AgW contacts were installed at a constant gap of 101 m in a closed container with a side of 1 Oc and 110 cubic meters, and an arc of a sinusoidal current of peak l Q KA was applied for 8 m5 (f seconds).
The pressure inside the container generated by the energy generated at this time is measured.

The inorganic highly porous material used in the above examples is a porous ceramic made by molding and sintering a ceramic raw material made of cordifite material using a method such as adding a combustible or foaming agent to make it porous. The apparent porosity of the porous material ranges from 10 to 300μ: 20%, 30%, 35%, 40%, 45%
, 50chi, 60%.

70%, 80%, 85%, 50jEIX 50
Various samples of 3 tNt were 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 region of the absorbed light, and the proportion of the surface occupied by the pores, that is, the specific surface area of the pores. Further, in terms of absorption of light within the pores, deep pores are effective, so continuous vents 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 in which the area occupied by the pores has an apparent porosity of 35 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 the effect. In experiments, it was confirmed that an average pore diameter of 5 μm to 1 ff showed good absorption characteristics for the light emitted by Arc A. In addition, the material is glass and the average pore diameter is 5μ.
It was observed that the 20μ absorbs the light emitted by Arc A well.

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. The effect was confirmed as the porosity increased with increasing size, especially when the porosity increased from 35% or more 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 a porous material is such that as the porosity increases, it becomes brittle, its thermal conductivity decreases, and it is more likely to melt due to high heat. The effect of reducing pressure 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. 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.

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. Note that organic porous materials have problems with heat resistance and gas generation, and metal porous materials have problems with insulation and pressure resistance, so the places where they can be used are limited.

By the way, in parallel with effectively absorbing the optical energy from the arc generated between the contacts using the above-mentioned specific material, it is also required to drive the arc quickly and improve the breaking capacity. .

In other words, the present invention is effective in cases where magnetic force acts on the arc generated when the contact is opened, and the internal pressure is suppressed by absorbing the light energy from the arc by providing a standing wall made of porous material. In addition, the purpose of the present invention is to provide a switch in which the apparent porosity of the vertical wall is varied so that the arc can be driven quickly and the breaking capacity can be improved.

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

FIG. 9 shows an example of a circuit breaker to which the switch according to the present invention is applied, and the same parts as in FIGS. 1 to 3 are denoted by the same reference numerals, and a description thereof will be omitted.

In the figure, on both sides of the electric contacts (4) and (7) in the width direction, there are contacts (6) and (
A vertical wall (to) is provided that extends from a position near point (9) along the direction in which the arc (to) is driven (arrow f in FIG. 10).

This vertical wall (to) is made of a porous material, such as an inorganic highly porous material.
a) , (+51)) , 1350). The vertical wall pieces), 135b), and C150) are set so that the farther forward they are located in the direction in which the arc is driven, the smaller their apparent porosity becomes.

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

First, the light energy radiated from the arc (b) generated when the contacts (6) and (9) are opened is absorbed by the vertical wall (b) made of an inorganic highly porous material.

In particular, the light energy on the front side of the arc (a), on the side of the vertical wall piece (15a) with apparently large porosity, is effectively absorbed by the vertical wall piece (15a) made of an inorganic highly porous material, and ) Since it does not heat itself, it is a vertical wall piece made of an inorganic highly porous material with a high porosity), (8)
) There is little conductive gas in the atmosphere of the area between the two, making it a space with relatively good insulation. On the other hand, the light energy on the rear side of the arc (151) and (150) side, which apparently has a small porosity, is absorbed at a lower rate than on the side with a larger porosity. Standing wall piece (15b), (+5b) or standing wall piece @○)
, $0), the temperature is high and there is a lot of conductive gas. Therefore, the arc easily moves to a space with a large amount of conductive gas. Therefore, due to the synergistic effect with the magnetic force acting on the arc (b), the arc (to) is quickly driven. That is, the internal pressure is suppressed and the arc is reliably driven, resulting in an improvement in the breaking capacity.

By the way, as a means for applying a magnetic force to the arc (b), in the above embodiment, a magnetic field generated by currents flowing in parallel and in different directions between the movable conductor (8) and the fixed conductor (5) acts on the arc (b). However, it is also possible to use a blowout coil or the like to apply magnetic force to the arc.

In addition, in the above embodiment, the vertical wall made of an inorganic highly porous material appears to be three vertical wall pieces 65a) with different porosity.
, C15b), and Cl50), but the number of divisions is not limited to this and can be changed as appropriate.

Of course, even if the vertical wall is not divided into a plurality of parts as in the above embodiment, the apparent porosity can be changed in each area or continuously in one vertical wall. There may be.

In the above embodiment, the vertical wall () is made of an inorganic highly porous material, but it goes without saying that it can be made of any other porous material as long as it is capable of absorbing light energy.

As described above, the present invention is capable of suppressing internal pressure by changing the apparent porosity of the vertical walls made of porous material and provided on both sides of the electrical contact in the width direction. In particular, it is possible to provide a switch which can significantly improve the breaking capacity.

[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 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 sectional view taken along the line X--X in FIG. 9. (3)...Container, (4), (7)...Electric contact, (fi), (8)...Conductor, (6), (
9)...Contact point, (to)...arc, (to)...standing wall. Note that the same reference numerals in the figures indicate the same or corresponding parts. Figure 1 Figure 2 Figure 3 Figure 4 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] (1) At least one pair of electrical contacts configured of a conductor and a contact fixed thereto and capable of opening/closing operations, and a container housing the electrical contacts, wherein the electrical contacts operate in an opening operation. Vertical walls are provided on both sides of the electrical contact in the width direction to receive the light energy of the arc generated when the electrical contact is applied. A switch characterized in that the setting is large on the side near the contact and small on the side moving away from the contact in the direction of contact. (2) The vertical wall is made of an inorganic highly porous material, and the inorganic highly porous material is selected from porous ceramics, refractories, guffs, and cement hardened bodies. 3. The switch according to claim 2, wherein the highly porous material has an average pore diameter of several thousand to several thousand micrometers.