JPS5828147A - Circuit breaker - 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 circuit breaker, and more particularly to a circuit breaker with improved current-limiting performance during interruption.

Fig. 1←) is a partially cutaway plan view showing a general circuit breaker, and No. 11W(1)) is 'b-b' in Fig. 1(a).
FIG. In this figure, (1) is an insulating enclosure that forms the outer frame of the circuit breaker, and is equipped with an outlet (101) on the side wall. (2) is a fixed contact,
a fixed conductor (201) fixed to the enclosure (1);
It consists of a fixed contact (202) fixed to the tip of this fixed conductor (201). (3) is the above fixed contact (2)
A movable contact that is paired with a movable conductor (301) driven by the operating mechanism section (4), and is fixed to the tip of this movable conductor (301) and makes contact with and separates from the fixed contact (202). It consists of a movable contact (302). (5) is an arc extinguishing plate that cools the arc A generated when the movable contact 002) separates from the fixed contact (202).

Now, when the movable contact (302) and the fixed contact (20z) are closed, the current flows from the fixed conductor (201) to the fixed contact (20z).
02)→movable contact (302)→movable conductor 001).

In this state, when a large current such as a short-circuit current flows through this circuit, the operating mechanism section (4) is activated and the movable contact (30
2) is separated from the fixed contact (202). At this time,
Arc A is generated between the fixed contact (202) and the movable contact (302), and the arc A is generated between the fixed contact (202) and the movable contact (302).
An arc voltage is generated between them. This arc voltage increases as the separation distance of the movable contact (302) from the fixed contact (202) increases. At the same time, the arc A is magnetically attracted and expanded in the direction of the arc extinguishing plate (5), so that the arc voltage further increases.

In this way, the arc current reaches the current zero point, the arc is extinguished, and the interruption is completed. During such critical operation, the movable contact (302) and the fixed contact (202)
A large amount of energy is generated within a short period of time, ie, several milliseconds, due to the direct arc. Therefore, the temperature of the gas within the enclosure (1) rises and the pressure also rises rapidly, but this high-temperature, high-pressure gas is discharged into the atmosphere from the outlet α01).

The circuit breaker and its internal components operate as described above when breaking the circuit breaker, but then the fixed contact (2
02) and the movable contact (302) will be particularly explained. Generally, arc resistance R is given by the following formula. That is, R = ρ - where R: arc resistance (Ω) ρ: arc resistivity (Ω, 1) l: arc length 1 B: arc cross-sectional area (d) However, generally at large currents exceeding and arc length l
In the case of a short arc of less than 50jEII, the arc space is occupied by metal particles.

Furthermore, the release of the metal particles occurs in a direction perpendicular to the contact surface. In addition, these released metal particles are
At the time of release, the temperature in the counterfeit is close to the boiling point of the contact metal,
Furthermore, as soon as it is injected into the arc space, it receives electrical energy and becomes high temperature and high pressure, becomes conductive, expands in the direction according to the pressure distribution of the arc space, and flows away from the conductor at high speed. It is something that leaves. The arc resistivity P and the arc cross-sectional area in the arc space are determined by the amount of metal particles generated and the direction in which they are released. Therefore, the arc voltage is also determined by the behavior of the metal particles.

Next, the behavior of such metal particles will be explained using FIG. 2.

In FIG. 2, the X-plane shows the opposing surface when the fixed contact (202) and the movable contact (302) come into contact, and the Y-plane shows a part of the contact surface and the conductor surface other than the above-mentioned X-plane. In addition, the ring z shown by the dashed-dotted line in the figure is a fixed contact (20
2) and the movable contact (3θυ).Furthermore, a and b are the fixed contact (202).
, is a schematic representation of each metal particle generated by evaporation from the X-plane and Y-plane of the movable contact (30cm).
The direction of release is the direction of each streamline indicated by arrow m and arrow n, respectively.

Such fixed contacts (202), movable contacts (302)
) are emitted from the metal particles a, b, which is heated by the energy of the arc space to about 3.000, which is the boiling point temperature of the conductor metal.
From about ℃ to the temperature at which it becomes conductive, that is, s, ooo
The temperature is raised to over °C or even higher, around 20,000 °C, and in the process of temperature rise, energy is removed from the arc space, lowering the temperature of the arc space and increasing the arc resistance R. . Metal particles a from the arc space,
The amount of energy taken away by b increases as the degree of temperature rise of the metal particles increases, and the degree of temperature rise increases at the point of contact (202).
, (302) is determined by the position in the arc space and the emission path of the metal particles a and b emitted from. However, in the conventional circuit breaker shown in Fig. 2,
Metal particles a emitted from near the center of the X-plane on the opposing surface take away a large amount of energy from the arc space, but,
Metal particles emitted from the contact surface and part of the Y plane of the conductor surface take away less energy from the arc space than metal particles a. In other words, metal particles a take away a large amount of energy within the flow range. Although it reduces the temperature of the arc space and therefore increases the arc resistivity ρ,
In the range where metal particles flow, a large amount of energy is not taken away, so the temperature of the arc space decreases little.
Therefore, it is not possible to increase the arc resistivity P, and furthermore,
Since the arc 7-A is generated from the opposing surface X and the different contact surface Y, the arc cross-sectional area 8 also increases, and therefore the arc resistance R also decreases.

Since the outflow of energy from the arc space by metal particles a and b matches the electrically injected energy, if contact point (202) = (302
) If the amount of metal particles generated between
The results show that it is possible to greatly increase the arc voltage by increasing the arc resistivity.

Furthermore, a major drawback of conventional contacts (2), (3) is that due to the expansion of the legs of the arc base to the Y plane, the contacts (202), (3) are generally often provided on this Y plane.
02) and the conductors (201) and (301), the legs of the arc A tended to expand directly at the joint, and the heat generated at that time melted the contact member, which has a low melting point, and there was a risk of the contact falling off. It is a point.

This invention has been made from the above point of view, and includes a pair of contacts consisting of a conductor and a contact fixed thereto, and a pressure reflector is provided on each of the conductors so as to surround the outer periphery of each of the contacts, In addition, by constructing at least one of the pressure reflectors with aluminum whose surface has been treated with a phosphate film, the arc voltage can be greatly increased, the current limiting performance at the time of interruption can be improved, and the contact can be prevented from falling off. The purpose is to provide a circuit breaker that enables

Embodiments of the present invention will be described below based on the drawings.

FIG. 3(a) is a partially cutaway plan view showing an embodiment of the circuit breaker according to the present invention, and FIG. 3(b) is a cross section taken along line b-b of FIG. 3(a). It is a diagram. Figure 3 (''),
In (1)), the enclosure (1) forming the outer frame of the circuit breaker is made of an insulator, and the outlet (1) is provided on the - side wall.
01). Fixed contact (2) is an enclosure (1)
Nine fixed conductors (201) fixed to
01) Fixed contact (202) attached to the O tip
It is composed of. The movable contact (3) opens and closes with respect to the fixed contact (2), and has a movable conductor (301), a fixed contact <202) K, and a good movable contact e02 attached to the tip of the movable conductor 001). ). The operating mechanism section (4) opens and closes the movable contact (3). The arc extinguishing plate (5) has a movable contact (30
2) extinguishes the arc that occurs when the contact point (202) opens from the fixed contact (202).

The fixed conductor (201) of the fixed contact (2) and the movable conductor (301) of the movable contact (3) have an outer station of the fixed contact (20, movable contact 002) provided thereon. A plate-shaped pressure reflector that surrounds and faces the arc base (
6) and (7) are installed.

Both the contacts (202) and (302) protrude from the pressure reflectors (6) and (7), and the pressure reflectors (a)
, (7) is made of aluminum whose surface has been subjected to a phosphate film treatment (allodine treatment).

Note that the arc-extinguishing plate (5) does not have to be used, but it is more effective to use it. Arc-extinguishing plate (5th one is made of magnetic or non-magnetic material, but if you use a non-magnetic arc-extinguishing plate,
Circuit breakers with high ratings have had problems with temperature rise during rated operation, and eddy currents caused by magnetic materials were a major cause of this problem, but this problem can be eliminated.

Now, in FIG. 3, when the movable contact (302) and the fixed contact (202) are closed, the current flows through the fixed conductor (202).
1) → Fixed contact (202) + Movable contact (302)
→Flows from the power supply side to the load side to the movable conductor (301). In this state, a large current such as a short circuit current flows through this (
9) When the fluid flows into the channel, the operating mechanism section (4) is actuated to separate the movable contact 002) from the fixed contact (202). At this time, an arc base is generated between the fixed contact (202) and the movable contact (302). In this arc base, as shown in Figure 4, the metal particles a and a are reflected by the pressure reflectors (6) and (7), creating a high pressure in the arc space, and as a result, the arc base is effectively cooled and extinguished. arced.

Figure 4 shows the fixed contacts (20
2) and a movable contact (302). FIG. That is, as can be seen from Fig. 4, the surrounding space QK of the contact points (202) and (302)
The pressure value at
Compared to the case where (7) is not provided.

It shows an overwhelmingly high value. Therefore, the pressure reflector (6)
The surrounding space Q, which has a considerably high pressure generated by , (7), exerts a force that suppresses the expansion of Arcum's space, and "squeezes" Arcum into a narrow space. This means that dead metal and metal grains are emitted from the opposing surface, the X-plane.
The streamlines such as children a and c are squeezed into the 1ook space and confined. Therefore, the metal particles &, C emitted from the X plane are effectively injected into the arc space. the result,
A large amount of effectively injected metal particles a and C remove a large amount of energy from the arc space, which is incomparable with conventional devices, and cool the arc space significantly. For this,
The arc resistivity P, that is, the arc resistance R increases significantly, the arc voltage increases significantly, and high current limiting performance is obtained.

Furthermore, the material of the pressure reflectors (6) and (7) is aluminum with a phosphate film treatment (allodine treatment) on the surface, but the phosphate film on the surface has insulating properties, so the legs of the arcum Contact (202), (302)
This is advantageous for pressure reflectors (6) and (7) that are exposed to arcuum, since the coating layer and the base material, aluminum, have high heat resistance. Also,
Since the base material is aluminum, it has very good heat conduction.
The heat on the surfaces of the pressure reflectors (6), (7) is quickly transmitted to the insides of the conductors (201), (301), and wear and tear on the surfaces of the pressure reflectors (6), (7) due to temperature rise can be suppressed. Also, even if exposed to Arcum,
A small amount of 4o gas is generated from the film, and the contact point (2
02), (302), there is no generation of harmful gases, and there is no influence (corrosion) on the contact points (202), (302) surfaces. In addition, the surface coating is a chemical conversion coating and has good adhesion to the base material, so the pressure reflector (6), (
7) withstands heat attack well. Furthermore, since the aluminum base material does not have to worry about cracking, the attachment is strong and reliable when caulked or otherwise crimped.

Moreover, since the base material of aluminum is lightweight, it does not affect the opening speed of the movable conductor (301), and therefore the current limiting performance does not deteriorate.

In addition, the base material aluminum has good castability, and pressure reflectors (6) and (7) of any shape can be easily manufactured.
It is very advantageous for pressure reflectors (6), (7) to be attached to conductors (201), (301).

Furthermore, due to the pressure reflectors (6) and (7), the legs of the arcum expand to the Y plane, and the contact points (202), (302) and conductors (201) generally provided on this Y plane. ), (301) (7) It is difficult for the leg of arc A to directly touch the joint, and as a result, the contact point (2
02), (302) has the advantage of eliminating the risk of falling off.

FIG. 5(-) is a side view showing another embodiment of the contacts (2) and (3), and FIG. 5(b) is a side view showing another embodiment of the contacts (2) and (3). ), (3) is a plan view. In other words, the pressure reflector (6), (7)/:r) has a conductor (201) extending in a direction away from the contact point (20, (302)) from one end side face to the outlet α01 side as a base point. ), (301)' are provided with grooves (601) and (701) such that their surfaces are exposed. In this configuration, the legs of the archum are grooved (601)
, (701), the arcum touches the arc extinguishing plate (5) and is cooled, improving the breaking performance.

Furthermore, as shown in Fig. 5, grooves (601) and (70
1) The exposed conductor surface is a pressure reflector (6),
It can be raised to the same level or higher than the surface of (7).

Figure 6(a) shows a contact (2
Figure 6 (1) shows a side view showing the embodiment of (3).
) is shown in Figure 6(a) and has nine contacts (2), (3)
FIG.

That is, as shown by ω01) and (901), the surfaces of the conductors (201) and (301) exposed from the grooves (601) and (701) are similar to the surfaces of the pressure reflectors (6) and (7). Shi is also prominent. With this configuration, the leg of arc A quickly reaches the outlet α0.
1), the interruption performance is improved and the wear of the contacts (202) and (302) is reduced.

As can be seen from the above description, according to the present invention, it is possible to provide a reversing interrupter that can greatly increase the arc voltage, improve the current limiting performance at the time of interruption, and prevent the contact from falling off. can.

[Brief explanation of the drawing]

! Figure 1 (-) is a partially cutaway plan view showing a general circuit breaker, Figure 1 (1)) is a cross-sectional view taken along line 'b-''b of Figure 1 (Figure 1), Figure 2 is Figure 1 3(-) is a partially cutaway plan view showing an embodiment of the circuit breaker according to the present invention, and FIG. Figure 4 is a schematic explanatory diagram of the behavior of metal particles in the circuit breaker of Figure 3, and Figure 5 (&) shows another example of the contact. 5(b) is a plan view of the contact shown in FIG. 5(a); FIG. 6(a) is a side view showing another embodiment of the contact; FIG. 6 CD) is a plan view of the contact shown in FIG. 6(a). (2)... fixed contact, (201)... fixed conductor,
(202)... Fixed contact, (3)... Movable contact,
(301)...Movable conductor, (302)...Movable contact, (6), (7)...Pressure reflector, (601)(
701)... Groove Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - (1 other person) (g) 1st Ward (a) (b) ) I214 Shi cod 3 figure

Claims (3)

[Claims] (1) For a pair of contacts consisting of a conductor and a contact fixed thereto, a speaking force reflector is provided on each conductor so as to surround the outer periphery of each contact, and the pressure reflector is A circuit breaker characterized in that at least one of the circuit breakers is made of aluminum whose surface has been treated with a phosphate film. (2) A circuit breaker according to claim 1, wherein at least one pressure reflector is provided with a groove such that the surface of the conductor is exposed in a direction moving away from the side surface of one end of the contact. vessel. (3) The circuit breaker according to claim 2, wherein the exposed conductor surface is raised as high as or more than the surface of the pressure reflector.