JPS58181234A - 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. Note that 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 generates an arc within a small container.

The present invention will be explained below using a circuit breaker 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 base, and the cover (1) and base (2) constitute a container (3). (4) is a fixed contact, which has a fixed conductor (5) and a fixed contact (
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) facing the fixed contact (6). The ring is a movable contact device, and the ring is a movable arm that is fixed to the crossbar (2) and is opened and closed at the time of each pole gap. (To) is the arc extinguishing chamber, where the arc extinguishing plate 04) is held by the side plate. (The top is a toggle link mechanism and consists of an upper link αη and a lower link. -Trip 0'7) One end is attached to the fredle (1ω), and the other end is attached to one end of the lower link (18). 2
0) Connected by (21). Please see the link below (
18) The other end of the movable contactor device (1■movable arm (
11). □□□ is the tilting type operation handle, (23) is the operating spring and the shaft of the toggle link mechanism (21)
) and the operating handle □□□.

In example (5), the trip bar (to) is rotated counterclockwise by the bimetal (a) and the movable iron core end when activated by the thermal and electromagnetic trip mechanisms, respectively.

(B) is a latch whose one end is locked to the trip bar (to) and the other end is locked to the fredle (19). If the fredl loquat is engaged with the latch (29) and the operating handle reaches the closed position in good condition, the toggle link machine 1ll (1B)
extends, 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 (support) is tilted to the open position, the toggle link mechanism is bent to connect the movable contact (9) to the fixed contact (6).
), and the movable arm (11) is locked to the fredl shaft (2). This state is shown in FIG. Furthermore, if an overcurrent flows through the circuit in the closed circuit state shown in Fig. 1, the thermal tripping mechanism or electromagnetic tripping mechanism (example) operates to release the engagement between the fredle (19) and the latch (29). , thereby moving Fredol (19
) rotates and is locked to the stopper shaft (31). Since the connection point between the fredle 0 (2) and the upper link (17) exceeds the line of action of the operating spring (support), the toggle link mechanism (16) is bent by the spring force of the operating spring (support), and the crossbar is bent.
(In accordance with 1, each pole is linked to perform automatic shutoff.

This state is shown in FIG.

Next, the behavior of arcs generated when current is interrupted in a circuit breaker 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)
It is supplied to the load side via sequentially. In this state, when a large current such as a short-circuit current flows through this circuit, the thermal tripping mechanism (to) or the electromagnetic tripping mechanism (25) acts to switch the movable contact (9) from the fixed contact as described above. (6) Separate from. At this time, an arc is generated between the fixed and movable contacts (61, (9)), and an arc voltage is generated between the fixed and movable contacts (61, (9)). As the separation distance of the movable contact (9) increases, the arc (321
is attracted and expanded by the magnetic force in the direction of the arc-extinguishing plate (14), so it further rises. 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 escapes completely out of the container in the form of thermal energy, but during the transient period until then, it increases the temperature of the limited gas inside the container. This will cause the gas pressure to rise rapidly. This had 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.

The reason for this drawback is related to the energy consumption mechanism of the arc. That is, FIG.
It is a diagram in which an arc A is generated between the contacts (4) and (7).

In the figure, T indicates the flow of energy due to light transmitted from the arc to the contact. In FIG. 8, the energy injected into the arc is divided into the three energy flows mentioned above, T and m.

Most of it is consumed by R. Of this, heat escape T to the electrode is minute, and most of the energy is carried away by m and R. Conventionally, m in Figure 1 was overwhelming in the energy consumption mechanism of the arc, and the energy of R was almost ignored, but recent research by the inventors has shown that the energy of R, that is, It was found that the energy consumed by light reached about 70% of the energy injected into the arc.

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

PW-V-I-PK+Pth+PR PK = 1mv"+ m-cP-T However, PW: Instantaneous injection energy ■: Arc voltage I: Current VI-I: Instantaneous electrical energy injected into the arc PK:
Instantaneous energy consumption carried away by metal particles 1 mv": Instantaneous energy consumption carried away when mg of metal particles fly away at velocity V m-CP-T: Gas with constant pressure specific heat CP (metal particle gas)
Instantaneous energy consumption taken away when escapes at temperature T Pth: Instantaneous energy consumption that escapes from the arc space to the electrode by heat conduction PR: Instantaneous energy consumption radiated directly from the arc by light The above consumption amount varies depending on the electrode shape and arc length, but for an arc of 10 to 20 mm, PK = 1.
0~20%, Pth=6% PR-75~8
It is 5chi.

Next, Figure 6 shows the situation when the arc is confined in a container. When the arc is confined in the container, the space inside the container is filled with metal particles of the electrode and becomes hot. In particular, the surrounding gas space Q of the arc positive column A (the 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 (3) 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 shown in the figure from Ra→Rb-+RC-
It is 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 spans all the wavelength ranges from far ultraviolet below 2000λ to far infrared above 1 μm, and consists of a continuous spectrum and a line spectrum. Even if the surface of a typical container wall is black, it only has the ability to absorb light in the range of 400λ to 5,000 people, and only partially absorbs light in other ranges. 1 is something that is almost always reflected. However, absorption in the arc space and surrounding high temperature gas space is as follows.

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

Ia −A book n peak LIin =・−(1
)■a: Mini gas absorption energy A: e, yield probability 11n: 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. A is the absorption probability for a specific wavelength λ (Lj),
It is a function of wavelength λ, gas temperature, and particle type.

Regarding equation (1), according to the teachings of quantum mechanics, the absorption coefficient is the largest for gases 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 most absorbed 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 a multiple of the number of reflections, υ, and in the high temperature part of the arc space. The amount of light energy absorbed will increase.

This means that the energy of the light emitted by the arc is
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 to solve the above-mentioned drawbacks, and consists of at least one pair of electrical contacts that open and close with each other, and which consists of a conductor and a contact fixed to the conductor. In a switch equipped with an arc-extinguishing plate for extinguishing an arc generated between both contacts, and a container for storing the contact and the arc-extinguishing plate, the arc-extinguishing plate is 1w7 of inorganic highly porous materials with a porosity of 861 or more
The object of the present invention is to provide a switch made of one or more types of composite materials.

In other words, in this invention, a material with a constant 41fI is used as the material of the arc extinguishing plate in order to effectively absorb the light energy which reaches about 70% of the energy injected into the arc. With this configuration, the light energy generated from the arc can be effectively absorbed, thereby absorbing a large amount of light inside the container, lowering the temperature of the gas space, and thereby reducing the pressure. It is something that makes you

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

Further, as the mesh, in addition to inorganic materials, metals, composite materials, etc., the mesh may also include multi-layered thin wire mesh, medium knitted wire, and the like.

This net also needs to have thermal strength.

Among the materials for the fibers and nets mentioned above, ceramics, carbon, asbestos, etc. are suitable for inorganic materials, and F for metals.
E, Cu is optimal, and Zn, Ni, etc. plated can also be used.

A porous material is a material that generally has a large number of pores within its solid structure, and exists in a wide range of materials such as metals, inorganic materials, and organic materials. One type is sintered and solidified at the points of contact between solid particles, and the other type is mainly composed of pores and the partition walls that form 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 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, which is the ratio of the volume of all open and closed pores contained in a porous material to the total volume (bulk volume) of the material. In other words, the true porosity is expressed as a percentage, and measurement methods include liquid or gas displacement and absorption methods, but a simple method is defined in JISR 2614, Method for Measuring Specific Gravity and Porosity of Fireproof and Insulating Bricks. It is calculated as follows.

On the other hand, the apparent porosity is the ratio of the volume of open pores to the total volume (bulk volume) of the material, i.e., expressed as a percentage, and the apparent porosity of JISR2206 firebrick is As defined in the method for measuring specific gravity, 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 pore volume and specific surface area, and it ranges from those close to the size of atoms and ions to the interfacial gaps between particles, ranging from several λ (angstroms) to a large diameter. It is generally 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.

To measure the specific surface area, the BET method is often used, which uses adsorption crosstalk at each temperature of various adsorbed gases.
In particular, nitrogen gas is often used.

Next, we will simulate 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, (to) indicates a highly porous inorganic material, and (to) indicates an opening leading to the surface of the inorganic material. The pore diameter of the open pores ranges from several microns to several square meters, and shows a wide range of sizes.

Now, as shown by R in FIG. 7, when light enters the opening of this porous material, it is reflected once when it hits the wall surface of the inorganic material. This occurs repeatedly inside the pores, and eventually it is absorbed into the wall 100 times. That is, the opening (to)
The incident light is directly absorbed by the surface of the inorganic material and becomes heat within the pores.

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

The experimental conditions were as follows: AgW contacts were installed at a constant gap of 10 in a cubic hermetic container with sides of 10 m, and the peak 10K
Generate an arc of sine wave current of A for 8 m5 (<9 seconds),
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 is in the range of 10 to 800μ, and the apparent porosity of the porous material is 20%, 80μ, and 85%, respectively.
, 40%, 45%, 60%, 60%, 70%, 80%,
Various samples measuring 50 x 50 x 8 wt were used and placed on the wall of the container so as 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 is slightly larger than one wavelength region of the absorbed light, and the ratio of the pores to the surface, that is, the specific surface area of the pores. In addition, for the absorption of light within the pores, deep pores are more effective, and continuous pores are preferable. The light generated from the arc in the switch is several hundred λ~
10,000 λ (1 μm), so it is suitable to have an average pore diameter that slightly exceeds this, that is, from several thousand λ to several thousand μm, and the area occupied by the pores on the surface has an apparent porosity of 85 or more. Highly porous materials are suitable for absorbing the light emitted by the arc. In particular, the effect is greater as the specific surface area of the pores whose upper limit is 1000 μm or less is larger. In experiments, it was confirmed that if a highly porous material with an average pore diameter of 6 μm to 1 μm is used, it exhibits good absorption characteristics for the light emitted by the arc. Furthermore, when the material was glass and the average pore diameter was bμ, 20μ, good light absorption was observed for the light emitted by the arc.

As can be seen from the characteristic curve a in FIG. 8, the pores of the inorganic highly porous material absorb light energy and have the effect of reducing the pressure inside the switch. This effect was confirmed in the range of 8611, as the apparent appearance of porous materials increases as the porosity increases9, especially when the porosity is 85% or more. 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 when the porosity increases, the material becomes brittle, its thermal conductivity decreases, and it is easily melted by high heat; In some cases, reducing the pressure inside the switch has little effect. Therefore, in practical terms, it is best to use a highly porous material with an apparent 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 main purpose is to protect organic containers from arcs. Therefore, when selecting an inorganic material, consider arc resistance, Emphasis was placed on characteristics such as lifespan, heat conduction, mechanical strength, insulation, and resistance to carbonization. An inorganic material that satisfies these characteristics is necessarily constructed with a tendency toward densification, and therefore, its purpose is different from that of this invention, and its apparent porosity is around GOS. There is.

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 suitable as a material to be installed inside the switch container, and since it is an electrical insulator, it will not have a negative effect on shutoff, and will not melt or melt even when exposed to high temperatures. Because 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, and the like, all of which can be used to reduce the gas pressure within the switch. Note that organic porous materials have problems with heat resistance and gas generation, and metal porous materials have problems with insulation and withstand voltage, so the places where they can be used are limited.

Hereinafter, a preferred embodiment of the present invention will be described with reference to FIG. 9 and FIG. 1θ. Incidentally, the main structure of the switch according to the present invention is the first one, taking a circuit breaker as an example.
Since the structure may be the same as that shown in FIGS. 8 to 8, only the essential parts of the present invention are shown in FIGS. 9 and 1θ.

In FIG. 9 and FIG.
). ), although it is functionally equivalent to
According to the present invention, there is shown an arc-extinguishing plate made of, for example, an inorganic highly porous material. These arc-extinguishing plates are made of inorganic highly porous material, that is, the apparent porosity is 85 or more, preferably 40.
~70%, and is made of an inorganic porous material with an average pore diameter of several thousand λ to several 1000 μm. fixed and movable conductors (5) in order to attract the arc A into contact with the arc-extinguishing plate (5).

(8) are formed with extensions (5 m) and (8 m), respectively. In order to extend this extension part (5a) in parallel with the fixed conductor (5), it is wound in a U-shape so that so-called electromagnetic repulsion is generated. In other words, a kind of arc driving means is provided. At this time, the contact (6) is positioned so as to face the contact (9) on the movable conductor (8). By doing this, it is possible to drive the arc person to the arc extinguishing plate (to),
Since the arc-extinguishing plate is made of an inorganic insulator, the arc A takes a curved path and has a long effective length as shown in the figure. Furthermore, since the arc extinguishing plate (5) is made of an inorganic highly porous material, a large amount of the light energy of the arc A is absorbed by the arc extinguishing plate (5), which causes ionization of the space around the arc person. is suppressed.Also, arc A is the contact point (
6) (Since it is pushed out from the 91 side and driven to the arc extinguishing plate (35) side, a large amount of light energy is absorbed by the arc extinguishing plate (35), and the internal pressure of the switch is effectively suppressed. be done.

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 relative to the standard value l, 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. Internal volume is 2an
It is a sealed container measuring 9 cm x 5 m deep and made of phenolic resin, which is an organic substance. The contacts of this actual device are made of AgW, which performs the breaking operation and generates a wave current arc of 8 mS (i9 seconds) with a peak value of 14 KA, and the energy generated at this time produces a This is a measurement of internal pressure.

The above-mentioned cordierite was used as the inorganic highly porous material constituting the arc-extinguishing plate (35). Average pore size range 1
The apparent porosity is 20% between 0μ and 800μ.

80%, 85%, 40cm, 50cm, 70cm, 2
Four samples of 0mX 20NIX 8x1 were 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, it can be seen that the use of an arc-extinguishing plate made of an inorganic highly porous material can have a remarkable effect on suppressing internal pressure.

By the way, the driving means for the arc A is not limited to the arrangement shape of the conductors, for example, the arrangement of parallel conductors as in the above embodiment to generate electromagnetic repulsion, but it is also possible to Possible means include having the side plates made of a magnetic material, or installing a blow-out coil.

In the above embodiment, the arc extinguishing plate ((5) is made of an inorganic highly porous material with a porosity of 85 cm or more, but it may be made of a porous material other than inorganic material. In addition to being able to be made of fibers or nets instead of the material, it is also possible to be made of a composite material of two or more of fibers, nets, and porous materials with a specific porosity.

As described above, the present invention provides an arc-extinguishing plate made of fibers, nets, and a composite material of one or more of porous materials with an apparent porosity of 85% or more. of light energy is effectively absorbed, and the internal pressure of the container can be reliably suppressed.

[Brief explanation of the drawing]

FIGS. 1-8 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 side sectional view showing the main parts of a circuit breaker incorporating the arc-extinguishing plate, and FIG. 11 is a perspective view showing an example of a circuit breaker according to an embodiment of the present invention. FIG. 3 is a characteristic diagram obtained from actual measured values of internal pressure. (3)...Container, (4), (7)...Electric contact, (5), (8)...Conductor, (6), (
9)... Contact, (to)... Arc extinguishing plate, A... Arc. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - (1 other person) Figure 1 Figure 2 Figure 2 24 b ” □・ Figure 3 Figure 4 RR Figure 8 Figure 9 Figure 10 Figure $11 Figure + (We met 4! (%)

Claims (4)

[Claims] (1) A conductor, at least one pair of electrical contacts fixed to the conductor and configured with nine contacts, which open and close within the container, and an arc extinguisher that extinguishes the arc that occurs between the circumferential contacts during the opening and closing operation. a plate, and an arc driving means for driving an arc in the direction of the arc extinguishing plate, and the arc extinguishing plate is made of fibers, nets, and porous materials with an apparent porosity of 85 or more.
Or a switch characterized by being composed of two or more types of composite materials. (2) The arc-extinguishing plate is made of an inorganic highly porous material, and this inorganic highly porous material has an apparent porosity of 40u70ts.
The switch according to claim 1. (3) The inorganic highly porous material is made of highly porous ceramics;
The switch according to claim 2, wherein the switch is selected from refractories, glass, and hardened cement. (4) The switch according to claim 2 or 8, wherein the inorganic highly porous material has an average pore diameter of several thousand λ to several thousand μm.