JPS5935339A - Switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to suppressing pressure within a container of a switch. Note that the term "switch" as used in the present invention particularly refers to a container such as a circuit breaker, current limiter, or electromagnetic switch, which typically generates an arc within a small container.

Hereinafter, a two-circuit breaker of the present invention will be explained as an example.

Are Figures 1 to 8 conventional circuit breakers? In the cross-sectional view shown,
Each one shows four different operating states.

(1) is a cover, (2) is a base, and the cover (1) and pace (2) constitute a container (3). (4) is a fixed contact, which has a fixed conductor (5) and has a fixed contact (
6) ',! 1', 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 tiled moving conductor (8), and has at one end a movable contact (9) facing the fixed contact (6). 00
(b) is a movable contact device, and (b) is a crossbar (2) with a movable arm.
), and each pole is opened and closed at the same time. Q3 is an arc extinguishing chamber, and an arc extinguishing plate Q→ is held by a side plate 06i. Q[G is a toggle link mechanism composed of an upper link Qη and a lower link θ section. One end of the upper link Qη is connected to the Freddle θ9), and the other end is connected to one end of the lower link Q8) by a shaft i (2+l).The other end of the lower link θ (to) is connected to the movable contact mentioned above. Child device Q
It is connected to the movable arm aυ of T3. (Incorporated) is a raised-type operating handle, and a row is an operating spring that is suspended between the shaft (21) of the toggle link mechanism and the operating handle. (24) (i!61) is a thermal and electromagnetic tripping mechanism, respectively, and when activated, the trip bar (c) is rotated counterclockwise by a bimetallic wire and a movable iron core (27).

One end of the kiln is locked to the trip bar (c), and the other end is locked to the trip bar (c).
Freddle (191 & is the latch that is locked. With Fredle (II) locked to the latch handle, press the operating handle (
When A) is turned to the closed position, the toggle mechanism 0119 is extended, the shaft t211 is locked to the fredle (19), and the movable contact (9) is joined to the fixed contact (6). This state is shown in Figure 1. Next, when the operation handle (2) is tilted to the open position, the toggle link mechanism Q0 is bent, the movable contact (9) is separated from the fixed contact (6), and the movable arm aυ It rotates and is locked on the fredle shaft (g). This state is shown in FIG. Furthermore, if an overcurrent flows through the circuit in the closed state shown in FIG. The engagement of (c) is released and the fredl shaft C30)? Fredol clockwise in the center (19)
rotates and is locked on the stopper shaft 0]). At this time, the connection point of Freddle θ9) and north link αη is the above-mentioned operating spring (
To cross the line of action of (b), the toggle link mechanism OQ is bent by the spring force of the operating spring (b), and the crossbar (2) is bent.
FIG. 8 shows this state in which automatic shutoff is performed in conjunction with each pole.

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)
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 movable contact (9) is separated from the fixed contact (6) as described above. At this time, an arc (9) is generated between the fixed and movable contacts (6) and (91), and the fixed and movable contacts (6)
, (9) An arc voltage is generated between. 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 arc C12
is attracted by the magnetic force and extends in the direction of the arc-extinguishing plate Q4, so that 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 transiently it increases the temperature of the gas inside the limited container and pulls it out. This will cause the gas pressure to rise suddenly and dramatically. 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.

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 the contacts (4) and (7). In the figure, T indicates the flow of thermal energy conducted from the arc 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. 8, the energy injected into the arc is almost consumed by the three energy flows mentioned above, T, m, and ll+.

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 the arc, m in the figure was overwhelmingly υ, and the energy of 几 was almost ignored, but recent research by the inventors has revealed that the average energy That is, it has been found that the energy consumption by light is so important that it reaches about 70 times the energy injected into the arc.

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

pw=V-1=PK 10Ptb +PRPK=-Hm
v"+m-Cp ・i' However, PW: Instantaneous injection energy V: Arc voltage I: Current ■・l: Instantaneous electrician energy PK injected into the arc
: Instantaneous energy consumption taken away by metal particles 7fflV" : Instantaneous energy consumption taken away when mg of metal particles fly away at speed V moCp-T: Gas with constant pressure specific heat Cp (metal particle gas)
Instantaneous energy consumption Pt1t carried away when escapes at temperature T: Instantaneous energy consumption PR2 that escapes from the arc space to the electrode by heat conduction Instantaneous energy consumption directly radiated from the arc The above consumption The amount changes depending on the electrode shape and arc length, but for an arc of 10 to 20 mm, PK = 1.
0-20 q6. Pth = 5chi, PR near 5~85
%.

What will happen next when the arc is confined in a container? It is shown in FIG. When the arc is completely confined in the container, the space inside the container is filled with electrode metal and reaches a high temperature.

In particular, the gas space Q around the arc positive column A (the space Q indicated by diagonal lines in the figure) ii: The above state is strong. Now, the light emitted from the arc is emitted from the arc positive column A, and is emitted from the container (3
) is irradiated and reflected by the wall. The reflected light is scattered,
The light passes through the high-temperature space filled with electrode particles again, and is irradiated onto the wall again. This process is repeated until the amount of light drops to zero.

During this time, the path of light is Ra → 1 in the diagram? ,b→&→&I
It is shown in

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

(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.Also, the light emitted from the arc ranges from deep ultraviolet light below 2000λ to far infrared light above 1μm. It consists of a continuous spectrum and a line spectrum, covering all wavelength ranges up to 100 nm. Even if the surface of a typical container wall is black, it only has the ability to absorb light in the range of about 4000λ to 5500λ, and in other ranges it only absorbs a portion of the light. It's mostly a reflection. However, absorption in the arc space and surrounding high temperature gas space is as follows.

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

Ia -A -n -LIin
--- (1) Ia: Absorbed energy by gas A: Absorption probability 1 inch: Irradiated light energy n: Particle density L 2 Optical path length through which light passes. Indicates the amount of energy. The probability of absorption for a particular wavelength is a function of wavelength input, gas temperature, and particle type.

Regarding equation (1), according to the teachings of quantum mechanics, the absorption coefficient A has the largest value for a gas 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. You will have a

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 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, L 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 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.

Therefore, the premise of this invention is to use a highly porous material in order to effectively absorb the light energy, which reaches about 70% of the energy injected into the arc, within the switch container. By placing a highly porous material that effectively absorbs the light emitted by the arc in the space that receives the energy of the arc's light, it absorbs a large amount of the light inside the container.
The gas empty November is intended to reduce the temperature and thereby reduce the pressure.

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 points of contact between solid particles, and the other type is composed mainly of pores and the partition walls forming the particles are solid materials. Note that in this invention, the term "raw material" refers to a material that is not shaped into a shape and is not processed 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 complex and can be roughly 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 can be calculated by a liquid or gas substitution method, an absorption method, etc., but as a simple method, it is calculated as follows, as defined in JISR2614, Method for Measuring Specific Gravity and Porosity of Fireproof 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 defined in JISR 2205 Method for measuring apparent porosity, absorption rate, and specific gravity of firebrick. As shown, it is calculated as follows. Note that the apparent porosity is also referred to as the effective porosity.

Pore diameters can be found from the measured values of pore volume and specific surface area, and range from those close to the size of atoms and ions to those that are several λ (angstroms) deep in the interfacial gap between particles. Defined as the mean value of the distribution. On the porous element side, the shape, size, and distribution of pores can be measured using a microscope or by the Suizome 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 highly porous material and the resulting drop in gas pressure, which is the premise of this invention.
This will be explained using an inorganic 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, 1331 is an inorganic highly porous material, (341 indicates an opening leading to the surface of the inorganic substance. Opening 04), and the pore size of the pore size varies from several liters to several mm.

Now, as shown by R in Fig. 7, when light enters this porous material (331),
Light hits the inorganic wall, is reflected, undergoes multiple reflections inside the pores, and is finally absorbed by the wall 100 times. That is, the light incident on the open-pore fermentation is directly absorbed by the inorganic surface mi and becomes heat within the pores.

Is Figure 8 an inorganic highly porous side slope? A curve diagram of the pressure change inside the model container when the apparent porosity of the inorganic highly porous material is incinerated is shown in the model container. In Figure 8, the horizontal axis is the porosity of the container, and the vertical axis is the inner wall f of the container.
7 The pressure when made of metals such as Cu, Fe, and AI is standardized as 1. The experimental conditions were as follows: An AgW contact was installed with a constant gap of 1101n in a cubic hermetic container with a side of 10 cm, and an arc of a sinusoidal current with a beam of 10 KA was generated for 8 mS (milliseconds), and at this time, the O energy was 4. - The pressure inside the container that occurs at - 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 of cordierite particles using a method such as adding a combustible or foaming agent to make it porous. Pore size range: 10~300μ, apparent porosity of porous material: 20%, 80mm, 85mm, 40mm, 45mm
Using samples of 50%, 60cm, 70cm, 80cm, and 85cm, each measuring 50mm x 50im x 4, these were placed on the wall of the container so as to cover 60cm of the inner surface area of the container. did.

Regarding the pore diameter, the issues are the average pore diameter, which is slightly beyond the wavelength range of the absorbed light, and the proportion of the surface occupied by the pores, that is, the specific surface area of the pores. For absorption within the pores of parents, deep pores are more effective, and continuous pores are preferred. The light generated from the arc in the switch is several hundred λ
~10,000λ (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 cm or more. Highly porous materials are suitable for absorbing the light emitted by the arc. In particular, the pore diameter is from several thousand λ to several thousand
The larger the specific surface area of the pores is in the μIn range, preferably the upper limit is 1000 μm or less, the more effective it is.

In experiments, it was confirmed that an average pore diameter of 5 μm to 1 μm exhibited good absorption characteristics for light emitted by an arc. In addition, when the material was gas and the average pore diameter was 5μ or 20μ, good light absorption was observed for the light emitted by the arc.

As can be seen from Figure 8, the pores of the inorganic highly porous material absorb light energy and have the effect of lowering the pressure inside the switch. In particular, the effect was confirmed when the porosity ranged from 85 cm or higher to 85 cm. Further increases in porosity require corresponding increases in the thickness of the highly porous material.

However, the appearance of porous materials is related to the porosity and mechanical strength; when the porosity increases, it becomes brittle, has low thermal conductivity, and is easily melted by high heat, and when the porosity is small,゛The effect of reducing pressure inside the switch is weak. Therefore, in practical terms, the most suitable porous material is a porous citrus material with an apparent porosity in the range of 40 to 70 inches.

The characteristic tendency shown in FIG. 8 is applicable to all inorganic p-porous materials, 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 arcs.1 Their properties include arc resistance, service life, heat conduction, and mechanical properties. Physical strength 1 insulation and carbonization prevention are required.
The inorganic material that satisfies these conditions (Δ material is necessarily composed of densification-oriented materials and has a different purpose, and its apparent porosity is 20
It is around 1.

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, there is little negative effect on shutoff, and it will not melt or emit gas even if exposed to high temperatures. Since it does not leak, it is ideal as a pressure suppressing material.

Porous inorganic materials such as porous ceramics, refractories, glass, and hardened materials can all be used to reduce the pressure of the gas in the switch.

Next, one embodiment of the present invention will be described based on FIG. 9. In the drawing, (51 (81) is a fixed contact (
6) A fixed conductor and a movable conductor to which a movable contact (9) is fixed, which constitute a fixed contact and a movable contact, respectively, and the contacts (6) and (9) of both upper neck contacts connect and disconnect. are placed opposite each other.

(88a) and (88b) are light absorbers, which are made of a porous material composed of an inorganic material or a composite material of an inorganic and organic material with an apparent porosity of 85 or more, and which are made of a porous material composed of an inorganic material or a composite material of an inorganic material and an organic material, and which have an apparent porosity of 85 cm or more, and which are ) (9) are arranged so as to sandwich the arc zero force generated between them from both sides.

(84a) (84b) are the light absorbers (88a) (8
8b) for the purpose of reinforcing the light absorber (88a) (18b).
) is a reinforcing plate integrally installed on the outer surface of the magnet, and is made of a non-magnetic metal plate such as copper, aluminum, or stainless steel.

The light absorber (88a) (88b) and the reinforcing plate (84a)
(84b) may be joined together using an adhesive, but heat bonding is effective.Heat bonding is performed using a light absorbing material (e.g. alumina, cordierite, magnesia). porous ceramics such as) and reinforcing plates (
When bonding to a metal plate), insert a copper plate between the light absorber and the reinforcing plate and heat it to about 1200°C. The molten copper will easily adhere to the reinforcing plate, and will also be absorbed into the structure of the light absorber. It penetrates and is integrally bonded. According to the switch configured as above, the arc generated between the contacts (61 (9)) is absorbed by the light absorbers (88a) (88b); in this case, the light absorbers (88a) Since the reinforcing plates (84a) and (84b) are installed on the outer surface of the switch (88b), the following effects can be achieved and a safe and highly reliable switch can be provided at a low cost.

(b) When the cover (1) and pace (2) are shut off, the pressure increase generated within the cover (1) and pace (2) is suppressed.
2) There is no need to pay special attention to mechanical strength, and the amount of material can be significantly reduced. Furthermore, if the amount of material is the same, it is possible to select an inexpensive grade of material with low mechanical strength.

(b) Since the rise in internal pressure at the time of shutoff is suppressed, the amount of sparks emitted from the switch is reduced, and secondary disasters such as power supply short-circuit accidents due to arcing when large current is shut off can be prevented.

(c) The risk of damage to the light absorber due to vibrations and shocks when the switch is transported or accidentally dropped, or shocks when a large current is cut off, is eliminated by installing a reinforcing plate. This reinforcing plate is especially effective when the light absorber is thin.

(c) Even if the light absorber is heated by the arc, heat can be efficiently conducted to the reinforcing plate, and burnout of the light absorber can be prevented.

(e) If an inorganic porous material containing zirconia or magnesia as a main component is used as the material for the light absorber, the surface of the light absorber will crystallize without vitrification when it reaches a high temperature due to direct exposure to the arc. , Good interrupting performance with no decrease in megohm on the surface of the light absorber during the arc period 75
E can be obtained.

(f) If the surface of a light absorber made of an inorganic porous material is heat-treated or an organic material is appropriately combined with an inorganic porous material, the effect of suppressing the increase in internal pressure will not be significantly hindered.
Precipitation of fine powder from the light absorber due to switch vibration and impact can be prevented.

In addition, FIG. 10 is a modification of the embodiment shown in FIG. 9 in which several metal plate de-ion arc-extinguishing plates Q4 are provided. According to this embodiment, in addition to the above-mentioned effects, arc-extinguishing Board Q4 cuff
- Reliable shutoff at the S current zero point can be achieved by direct cooling.

[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 is generated between contacts. Figure 5 is an explanatory diagram showing how an arc force is generated between contacts in a container. Figure 6 is an inorganic highly porous material. 7 is a partial enlarged sectional view of FIG. 6, and FIG. 8 is a curve diagram showing the change in pressure inside the container with respect to the apparent air-drying rate when an arc is generated.
FIG. 9 is a perspective view partially showing one embodiment of the invention, and FIG. 10 is a perspective view partially showing another embodiment of the invention. In the figure, (5) is a fixed conductor, (6) is a fixed finger, and (1) is a fixed conductor.
8) is a movable conductor, (9) is a movable contact, a4 is a deion arc extinguishing plate, (88a888L)) is a light absorber, (84a)
(84b) is a reinforcing plate. Note that the same reference numerals in the drawings indicate the same or fourth eye portions, respectively. Agent Makoto Kuzuno - Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 J,, 71 Figure 10

Claims (5)

[Claims] (1) In a device that has at least one pair of contacts that open and close, consisting of a conductor and a contact fixed to the conductor, the appearance of the material is inorganic or inorganic with a porosity of 35% or more. A light absorber is formed of a porous incline made of an organic composite material and is disposed so as to sandwich the arc generated between the contacts from both sides at the time of breaking, and the outer surface side of the light absorber. A switch comprising a reinforcing plate made of an inverted non-magnetic metal that is integrally stacked with the light absorber. (2) The switch according to claim 1, wherein the surface of the light absorber is hardened by heat treatment. (3) The switch according to claim 1 or 2, wherein the light absorber is made of magnesia or zirconia. (4) The switch according to any one of (1) and (1) of claims 1 to 8, wherein the light absorber and the reinforcing plate are superimposed by heat bonding. (5) According to any one of claims 1 to 4, a plurality of deion arc-extinguishing plates made of magnetic material are arranged between the opposing light absorbers. The switch mentioned.