JPS58181232A - 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 a switch. The term "switch" used in the present invention particularly refers to a circuit breaker, a current limiter, an electromagnetic switch, etc., and usually means a switch that causes a disconnection within a small container.

The present invention will be explained below using a circuit breaker as an example.

Figures 1 to 6 are cross-sectional views showing conventional circuit breakers.
Each shows a different operating state.

(1) is a cover, (21 is a base, and the cover (1) and base (2) constitute a container (8). (4) is a fixed contact, which has a fixed conductor (5), and Fixed contact at one end (
6), and the other end is a terminal portion to be connected to an external conductor (not shown). (7) is a movable contact, which has a movable conductor (8), and has at one end a movable contact (9) opposite to the fixed contact (6). αO) is a movable contact device, (11) is a movable arm that is fixed to the crossbar (B), and each pole is opened and closed at the same time. (18
1 is an arc extinguishing chamber, and an arc extinguishing plate (b) is held by a side plate (I51). (16) is a toggle link mechanism with an upper link αη
It is composed of and Shimolink (goods). One end of the upper link α force is attached to Fredol 09), and the other end is attached to the lower link (18
) at one end of each axis (sha).

They are connected by ψ0. The other end of the lower link (E) is connected to the movable arm (11) of the movable contact device α(2). The 0th layer is an up/down type operating handle, and (c) is an operating lever, which is stretched between the axis @0 of the toggle link mechanism 06) and the above operating handle @gong. Q: Rumor has it that when operating with thermal and electromagnetic tripping mechanisms, the re-drip bar (c) is rotated counterclockwise by bimetallic and movable iron cores, respectively. . 2) is a latch whose one end is locked to the trip bar (c) and the other end is locked to the fredle (1g).

If you tilt the operating handle to the closing position while it is locked to the fredle (latched), the toggle link mechanism 06)
extends, the shaft (21) is locked to the fredle 09), and the movable contact (9) is joined to the fixed contact (6). This state is shown in FIG. Next, when the operating handle (06) is tilted to the open position, the toggle link mechanism (06) is bent to open the movable contact (9).
) is opened from the fixed contact (6) to lock the movable arm (11) to the fredle shaft O0. 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 (c) or electromagnetic tripping mechanism (c) will operate, causing the fredle (19) and the latch to operate.
- As a result, the fredle (19) rotates clockwise around the stopper shaft 0 (step 0) and the stopper shaft 0.
It is locked at 0. Since the connection point between the fredl (19) and the upper link αη crosses the line of action of the actuating spring (c), the toggle link mechanism 06) is bent by the spring force of the actuating spring (c), and the crossbar (2) Each pole is linked and automatically shuts down. This state is shown in FIG.

Next, the failure that occurs when the current is cut off in a circuit breaker.
Explain the behavior of

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)
It is supplied to the load side through all sequential steps. In this state, when a large current such as a short-circuit current flows through this circuit, the thermal tripping mechanism (c) or electromagnetic tripping mechanism (c) acts as described above, switching the movable contact (9) from the fixed contact. (6) Separate from. At this time, an arc is generated between the fixed contact (6) and the movable contact (Ω), and an arc voltage is generated accordingly. This arc voltage increases as the separation distance of the movable contact (9) from the fixed contact (6) increases, and at the same time, the
It rises further because it is attracted by the magnetic force and expands in the direction of the bend. In this way, the arc current reaches a current zero point, the arc is extinguished, and the interruption is completed. However, this injected beautiful arc energy eventually becomes thermal energy and completely escapes from the container, but during the transient period up to that point, it increases the temperature of the gas inside the limited container, and This will cause the gas pressure to rise rapidly. This resulted in serious drawbacks such as deterioration of the insulation inside the circuit breaker, power supply short-circuit accidents due to an increase in the amount of sparks emitted to the outside of the circuit breaker, and destruction of the circuit breaker itself.

Specifically, the reason for this drawback is related to the energy consumption mechanism of the arc. That is, Fig. 4 is a diagram in which a gap A has occurred between the contacts (41 and (7)). In the figure, T is the flow of thermal energy that is conducted from the gap to the contact and escapes, and m is the arc The energy flow of metal particles escaping from the space -R indicates the energy flow due to light escaping from the arc space.In Fig. 6, the energy injected into the arc is divided into the three energy flows mentioned above, T, Most of the heat is consumed by m and H. Among these, the heat escape T to the electrode is minute.
Most of the energy is carried away by m and R. Conventionally, in the energy consumption mechanism of the arc, m in the figure was overwhelming, and the energy R was almost ignored, but recent research by the inventors has revealed that it is just an energy consumption injection. It turned out that the amount of energy generated by the students was approximately 70%.

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

Pw=V・knee Pk+Pth+FB Pk='mV' +m −op, T However, PW: Instantaneous injection energy V Air voltage: Current ■・1: Instantaneous electrical energy injected into the arc Pk:
Instantaneous energy consumption taken away by metal particles Instantaneous energy consumption taken away m・0p-T: Gas with constant pressure specific heat Op (metal particle gas)
Instantaneous energy consumption pth carried away when escapes at temperature T ; Instantaneous energy consumption Pth that escapes from the arc space to the electrode by heat conduction P & Instantaneous energy consumption directly radiated from the two The amount varies depending on the electrode shape and arc length, but for an arc of 10 to 20 seams, pk = 10.
-20%, Pth=5%, PR=75-85%.

Next, Figure 5 shows the situation when the arc is confined in a container. When the arc is confined in a container, the space inside the container is filled with metal particles from the electrode and becomes hot. In particular, the surrounding gas space Q of Ryo-Yuhi Aborigine A (space Q indicated by diagonal lines in the figure)
The above condition is severe. Now, the light emitted from the arc is emitted from the arc positive column A, and is irradiated onto the wall of the container (8) and reflected. The reflected light is scattered, passes through the high-temperature space filled with electrode 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&→Rb -SRo in the figure.
→ Indicated by Rd.

In the above process, the light emitted from the arc is consumed in the following two ways.

(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. The light emitted from the arc covers the entire wavelength range from the far ultraviolet below 12,000 A to the far ultraviolet above 1 μm, and consists of a continuous spectrum and a line spectrum. Even if the surface of a typical wall is black, it only has the ability to absorb light in the range of 4000A to 5500A, and in other ranges it absorbs only a portion and reflects almost nothing. It's something you end up doing. However, the absorption in the ryokan space and the surrounding high temperature gas space is as follows.

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

Engineering a=A-n-Llin-(1
)Equation sL=Absorbed energy by gas A: Absorption probability 11n: Irradiated light energy n Two-particle density L Length of the optical path through which the two particles pass. However, equation (1) shows the total absorption energy for a specific wavelength λ. A is the absorption probability for a specific wavelength λ, and is a function of wavelength λ, gas temperature, and particle seed.

Regarding equation (1), according to the teachings of quantum mechanics, a gas with one absorption coefficient AGj and both terminal and line spectra in the same state as the light source gas that emits light (that is, the type of particles and temperature are the same)
will have the largest value.

That is, the light emitted from the arc space is most absorbed in the arc space and the surrounding gas space.

In equation (1), the absorbed energy 11a 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, L in equation (1) increases by a multiple of the number of reflections, and the high temperature area of the arc space increases. This results in an increase in the amount of light energy absorbed.

This means that the energy of the light emitted by the light is ultimately
This means that it is absorbed by the gas in the container, thereby increasing the temperature of the gas and increasing the pressure of the gas.

The present invention has been made in order to solve the above-mentioned drawbacks, and includes at least one pair of fixed and movable contacts, which are made up of a conductor and a contact fixed to the conductor, and which open and close with each other; In a switch having a notch on the opposing front end surface and including an arc extinguishing plate for extinguishing an arc generated between the two contacts during an opening operation, and a container for storing the above-mentioned contactor and the above-mentioned arc extinguishing plate, A panel covering at least the gap between the inner wall of the notch and the contact point is disposed above the arc-extinguishing plate, and the panel is made of fibers, net, and an apparent porous material with a porosity of 65% or more or The object of the present invention is to provide a switch in which the above-mentioned panel is made of two or more types of composite materials.

That is, in this invention, a specific material is used in order to effectively absorb the light energy, which reaches about 70% of the energy injected into the arc. Specifically, fibers, nets, and highly porous materials with an apparent porosity of 35% or more are installed in specific positions within the switch container that receive the energy of the arc light to effectively absorb the light emitted by the arc. one of them
By selectively arranging a species or two or more species,
By absorbing a large amount of light inside the container, the humidity in the large space is lowered, thereby lowering the field strength.

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

Also, the net and 1. Then, materials such as inorganic threads, metals, composite materials, etc., multi-layered thin wire meshes, and net wires can also be selected.

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;
Pe and Ou are most suitable, and those plated with Zn, Ni, etc. are also applicable.

A porous material is generally a material with a large number of pores within its solid structure, and exists in a wide range of materials such as metals, 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 in this invention, the term "material" refers to the original material that is not shaped into a shape, but before being transformed 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 complicated and 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.

There are two types of porosity: true porosity and apparent porosity.The ratio of the volume of all open and closed pores contained in a porous material to the total volume of the material 4ilI (bulk volume) In other words, the true porosity is expressed as a percentage, and measurement methods include liquid or gas displacement and absorption methods, but as a simple method, it is defined in the method for measuring the specific gravity and porosity of fireproof and insulating bricks in J.K. 5R2614. It is calculated as follows.

Bulk Specific GravityOn the other hand, the apparent porosity is the ratio of the volume of one open pore to the total volume of the material (bulk volume), that is, expressed as a percentage. As defined in the method for measuring porosity, absorption rate, and specific gravity, it is calculated as follows.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 it ranges from the size of an atom or ion to the interfacial gap between particles, ranging from a few angstroms to the bottom. is defined as the average value of

For porous materials, the shape, size, and distribution of pores can be determined using a microscope or mercury intrusion method. In general, it is preferable to use a microscope directly to accurately understand the complicated shape and distribution of pores.

To measure the specific surface area, the BFIT method, which is determined by using adsorption isotherms at various temperatures of various types of adsorbed gases, is often used, and nitrogen gas is particularly often used.

Next, we will explain the absorption of light energy by a highly porous 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, - indicates a highly porous inorganic material, and ■ indicates an opening leading to the surface of the inorganic material. The pore diameters of the open pores 04 range from several microns to ＠kaku, showing a wide range of sizes.

Now, when light enters the opening (2) of this porous material, as shown by R in FIG. 7, the light hits the wall surface of the inorganic material and is reflected. This occurs repeatedly inside the pores, and eventually 100% of the material is absorbed by the walls. That is, the light incident on the opening 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 Figure 8, the horizontal axis is the apparent porosity, and the vertical axis is the inner wall of the container.
The pressure when made of metal such as k OuI"*" is normalized as 1.

The experimental conditions were as follows: A total of 10 AgW contacts were installed at a fixed gap in a cubic closed container with a -side of 10 crn, and the peak 1
An arc of 0 KA sine wave current was generated for 18 m5 (milliseconds), and the pressure inside the container generated by the energy at this time was measured.

The inorganic highly porous material used in the above examples is porous ceramic made by molding cordierite ceramic raw material by adding flammable or foaming agents and sintering it into a single pore, with an average pore size. is in the range of 10 to 600μ, and the apparent porosity of the porous material is 20%, 60%, and 35%, respectively.
, 40%, 45%, 50%, 60%, 70%, 80%,
Various samples of 85% and 50++II++ x 50cm x 3mm were used and placed on the wall of the container so that they covered 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 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 pore absorption of light, deep pores are effective, and continuous pores are preferable.

Furthermore, the light generated from the arc in the switch is several hundred A to 10
000 A (1 μm), so it is suitable to have an average pore diameter slightly larger than this, i.e. from several thousand A to several thousand μm. Porous materials are suitable for absorbing the light emitted by the arc. In particular, in experiments where 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 is, the more effective the effect is. It was confirmed that it exhibits absorption characteristics. In addition, the average pore diameter is 5μ for the material *, plus.

When the thickness was 20μ, good light absorption was observed for the light emitted by the arc.

As can be seen from the special curve a in FIG. 8, the pores of the inorganic highly porous material absorb light energy and have the effect of lowering the pressure inside the switch. This becomes thicker as the apparent porosity of the porous material increases, and becomes particularly noticeable when the porosity is 65% or more, and the effect was confirmed up to 85%. Further increases in porosity require corresponding increases in the thickness of the highly porous material.

However, in terms of the relationship between porosity and mechanical strength, the apparent porosity of a porous material is large (if the porosity is large, it will become brittle, the thermal conductivity will drop and it will easily melt due to high heat, and on the other hand, if the porosity is small) In this case, the effect of reducing the pressure inside the switch is weak.Therefore, in practical terms, a highly porous material with a porosity in the range of 40 to 70% 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 their main purpose is to protect organic containers from arcs. Therefore, when selecting lead-free gravel materials, it is important to Emphasis is placed on properties such as durability, lifespan, heat conduction, mechanical strength, insulation and carbonization prevention. An inorganic material that satisfies these characteristics is necessarily constructed to be densified, and therefore has a different purpose from the present invention, and its apparent porosity is around 20%.

Highly porous materials include inorganic, metallic, and organic materials, among which inorganic materials are characterized as insulating materials and high melting point materials. These two properties make it suitable as a material to be installed inside the switch container, and since it is an electrically supplied material, it does not have any adverse effects on shutoff, and even when exposed to high temperatures, Since it does not melt or emit gas, it is ideal as a pressure suppressing material.

Examples of inorganic porous materials include porous ceramics, refractories, glass, and hardened cement, all of which can be used to increase the pressure of the 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 durability, so the places where they can be used are limited.

Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. 9 and 10. The main structure of the switch according to the present invention is shown in FIGS. 1 to 3, taking a circuit breaker as an example.
Since the configuration may be the same as that shown in the figure, only the essential parts of the present invention are shown in FIGS. 9 and 10.

In FIGS. 9 and 10, each arc extinguishing plate 041 has a substantially U-shaped notch (140) formed on the front end surface facing the contacts (6) and (9). Part (14
A movable conductor (8) of a movable contact (γ) moves within 1n during opening and closing operations. However, when the movable conductor (8) separates from the fixed conductor (5), an arc is generated as described above.
) contact point (6) between the inner wall surface (14Qa) and the movable conductor (8)
The gap between the two, that is, the space V indicated by diagonal lines in FIG. 10, becomes a flow path for the luminous gas f generated as the arc occurs. To be more specific, the gas f generated with the generation of the arc is emitted in all directions, but most of it is blown up upward in FIG. 9 with intense force through the flow path. The force of the gas flow in this channel is strong regardless of the separation distance between the contacts (6) and (9).

Therefore, as shown in Fig. 9, a panel made of an inorganic highly porous material and covering the void VT is placed above the movable conductor (8) and above the uppermost arc-extinguishing plate (b). Thus, the gas flow f flowing upward through the above-mentioned flow path directly hits the flow path. In this way, the gas flow f comes into contact with and is absorbed by the panel made of inorganic highly porous material. gas flow f
The mechanism by which light is absorbed in this manner is as described above, and it goes without saying that the effect of absorbing light energy from light A is exerted. Furthermore, since the panel is made of inorganic material, thermal energy is directly taken away due to the unique heat absorption ability of inorganic material, which is comparable to that of metals. At the same time, since the panel (G) is porous, the contact area with high-temperature gas is large, and therefore the heat exchange effect is also significant. It goes without saying that this heat exchange effect can be further promoted if the material has pores consisting of ventilation holes even if the porosity is the same.

FIG. 11 shows an actual measurement example based on an embodiment of the present invention.

In the figure, the horizontal axis is the apparent porosity, and the vertical axis is the pressure value shown in comparison with the standard value 1, which is the pressure inside the container at the time of arc occurrence in the standard product.

The experimental conditions are as follows.

An actual machine with a 50A frame was used. Inner volume is 2cm
It is a sealed container measuring 9 cm x 5 crn in depth, and is made of phenolic resin, which is an organic material.

The contacts of this actual machine are made of AgW, which performs the normal breaking operation and generates an arc of 15 m5 (mi! J seconds) of a half-sine current with a peak value of 14 KA, and the internal pressure generated by the energy at this time is reduced. This is what was measured.

The above-mentioned cordierite was used as the inorganic highly porous material constituting the vertical wall (c). Average pore size range 10μ
~300μ, the apparent porosity is 20%, 60%, 65%, 4
0%, 50%, 70%, 20 am x 20
One sample of order x 6 cabinets was used.

In the figure, the curves are characteristic curves obtained from actual measurements.

The black point a is the same as the measured value a in FIG.

As is clear from the above characteristic curve, a panel made of an inorganic highly porous material is specifically installed on the arc extinguishing plate.
By simply bringing the arc Ai into contact with the above-mentioned panel, it is possible to suppress the rise in temperature and pressure within the container (8) described above, and therefore it is possible to prevent the switch from bursting. This is very useful as it extends the life of the switch.

By the way, in the above embodiment, in the panel extending from the arrangement position of the contacts (a), to) to the rear end of the arc-extinguishing plate, the inner wall of the notch of the above-mentioned contacts (6), tQ) and the arc-extinguishing plate 0 (
140a), the panel shape is not limited, and for example, the first
As shown in FIG. 2, the horse-shaped panel (350) may be smaller as long as it is smaller than the above-mentioned void V'e'.

Further, in the above embodiment, the panel is made of an inorganic highly porous material with an apparent porosity of 65% or more, but it may be made of a porous material other than an inorganic material, or it may be made of a porous material instead of a porous material. It can be constructed from fibers or mesh, or it can be constructed from a composite material of two or more of fibers, mesh, and porous material with a specific porosity.

As described above, in this invention, a panel made of a specific material is specifically provided on an arc-extinguishing plate, and the luminous gas is made to collide directly with the panel using the gas flow generated by the arc. , the internal pressure can be effectively suppressed.

[Brief explanation of drawings]

FIGS. 1-6 are cross-sectional views of conventional circuit breakers, each showing different operating conditions. Figure 4 shows the distance between the contacts.
Fig. 5 is an explanatory drawing showing how arcing occurs between contacts in the container, Fig. 6 is a perspective view showing the inorganic highly porous material, Fig. 7 is an explanatory drawing showing how arcing occurs between contacts in the container, FIG. 8 is a curved line showing changes in the internal power of the container with respect to the apparent porosity when an arc is generated. FIG. 9 is a cross-sectional view of a main part of a switch according to an embodiment of the present invention. FIG. 10 is a top view of the main part of FIG.
FIG. 2 is a top view showing a modified structure of the main part of the present invention. (8)... Container, (4)... Fixed electrical contact, (5
)...Fixed conductor, (6)...Fixed contact, (7)...
・Movable electric contact, (8)...Movable conductor, (9)...
・Movable contact, 0 (rolling)... arc extinguishing plate, -... nosenel, (140)... notch, (140a)... inner wall surface, A... arc, V... void . Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno (1 other person) (c) Figure 1 Figure 2 - l'l 1711 Rule 65

Claims (4)

[Claims] (1) at least one pair of fixed and movable electrical contacts, each consisting of a conductor and a contact fixed thereto, which open and close within the container; an arc-extinguishing plate that extinguishes an arc generated during the opening operation of the liquid contactor, and a panel that covers at least the gap between the inner wall surface of the notch and the contact point is disposed above the arc-extinguishing plate;
A switch characterized in that the panel is made of a composite material of one or more of fibers, nets, and porous materials with an apparent porosity of 65% or more. (2) The switch according to claim 1, wherein the panel is made of an inorganic highly porous material, and the inorganic highly porous material has an apparent porosity of 40% to 70%. (3) The above inorganic highly porous material is ceramic with high porosity ~
The switch according to claim 2, wherein the switch is selected from the group consisting of large objects, glass, and hardened cement. (4) The switch according to claim 2 or 5, wherein the inorganic highly porous material has an average pore diameter of several thousand to several thousand μm.