CN115440535A - Breaking device - Google Patents

Abstract

The invention relates to a breaking device, which comprises a moving contact and a fixed contact, wherein the moving contact is provided with a motion track relative to the fixed contact so as to realize the connection and disconnection of the breaking device, the breaking device also comprises an arc-extinguishing grid sheet group formed by arranging a plurality of arc-extinguishing grid sheets, the arc-extinguishing grid sheet group is fixedly arranged at one side facing to the motion track, the breaking device also comprises a permanent magnet, the permanent magnet is fixedly arranged at one side of the arc-extinguishing grid sheet group back to the motion track, the direction from the motion track to the permanent magnet is defined as the up-down direction, and the permanent magnet is arranged along the up-down direction with the orientation of two magnetic poles of the permanent magnet. The permanent magnet is arranged on the outer side of the arc extinguish chamber, so that the influence of a large amount of heat generated when electric arc is generated can be avoided, the phenomenon of high-temperature demagnetization can not be generated, charged particles generated when the electric arc ablates a contact can be attracted to be flushed out of the arc extinguish chamber, and the breaking capacity of the circuit breaker is improved. Each pole circuit breaker only needs a permanent magnet to realize the nonpolar magnetic quenching effect of the circuit breaker, and the cost is greatly reduced.

Description

a breaking device

technical field

The invention relates to a breaking device, in particular to the improvement of the magnetic blowout structure.

Background technique

How to improve the breaking capacity of circuit breakers has always been a key research direction in the industry. In recent years, with the development of new energy technology, the rated operating voltage of DC circuit breakers has become higher and higher, and has reached 1500V at present. Due to the increase of working voltage, the market puts forward higher requirements for the reliable breaking performance of circuit breakers, and the difficulty of critical breaking will increase significantly.

At present, the commonly used technologies to enhance arc extinguishing ability, such as extending the arc by increasing the opening distance and promoting and cooling the arc by burning gas-generating materials, however, in the case of high DC voltage and limited volume, these The method will not be able to reliably break the circuit, and it is difficult to quickly introduce the arc into the arc extinguishing chamber to extinguish the arc by relying on the traditional single air blowing. In addition, since the DC current has no natural zero-crossing point, it is difficult for the DC molded case circuit breaker to break the DC short-circuit current, especially in the high-voltage DC short-circuit current.

Therefore, existing circuit breakers often use permanent magnets to provide an external magnetic field, so that the arc is elongated and quickly enters the arc extinguishing chamber. The traditional permanent magnet magnetic blowing acceleration scheme is generally shown in Figure 1-2. The circuit breaker includes a moving contact 200 and a static contact 100. The moving contact 200 can swing relative to the static contact 100, and the circuit breaker is realized by its motion trajectory. The arc extinguishing grid group 300 is arranged on one side of the moving track of the moving contact 200 to extinguish the arc 400 generated during the breaking process, and the two sides of each arc extinguishing grid group 300 in the width direction are respectively A permanent magnet 500 is provided, and the magnetic poles of the permanent magnet 500 are arranged laterally along the width direction of the arc extinguishing grid group 300, so that the direction of the magnetic field that the permanent magnet 500 acts on the arc 400 is roughly along the width direction of the grid. The magnetic field between the opposing permanent magnets 500 generates an ampere force F _A on the arc, so as to stretch the arc 400 to move toward the arc extinguishing grid set 300 .

However, in this scheme, the distribution of permanent magnets and the flow direction of the arc current have certain configuration requirements, and the non-polarity condition cannot be achieved. For example, in the case of Figure 2, the current of the arc 400 is reversed (that is, the current flow direction is changed from the paper to outside), the arc 400 will move towards the contact system, which is not expected and is not conducive to breaking the arc. Nowadays, in many application scenarios (such as photovoltaic and wind power), the DC circuit breaker will face the situation of breaking the reverse DC current, so this structure cannot be used in applications with non-polarity requirements.

In this regard, some existing manufacturers have developed a non-polar magnetic blowout structure. For example, the patent CN209071258U proposes a circuit breaker with a permanent magnet. Refer to the accompanying drawings 1-3 of this patent. This patent chooses to The permanent magnet 4 is added on the grid piece 3, and the magnetic pole connection direction of the permanent magnet 4 is parallel to the extension direction of the arc extinguishing grid piece 32, so that the magnetic field direction of the permanent magnet 4 acting on the arc is roughly along the height of the grid piece Longitudinal, so that regardless of whether the direction of the arc current is forward or reverse, the arc will be stretched and extinguished by the transverse ampere force toward the arc extinguishing grid 32 , which realizes the requirement of non-polarity.

However, in the structure of the patent CN209071258U, the permanent magnet 4 is added on the grid piece 3, and the grid piece 3 is arranged closely, so it is difficult to assemble the permanent magnet 4 on the grid piece 3, and it is particularly important More importantly, since the permanent magnet 4 is too close to the arc, a large amount of heat generated in the arc extinguishing chamber will affect the magnetism of the permanent magnet 4 and cause high-temperature demagnetization. Therefore, in this patent, the permanent magnet 4 must be covered with insulation Moreover, the heat-insulated casing 41 increases the cost and difficulty of manufacture. At the same time, a large number of charged particles produced when the arc burns the contacts at high temperature will be difficult to rush out of the arc extinguishing chamber due to the attraction of the permanent magnets 4 on both sides of the arc, which will affect the next breaking capacity of the circuit breaker.

In addition, in the above two structures, the number of permanent magnets used in each arc extinguishing chamber ranges from 2 pieces to as many as 4 pieces, and the volume is relatively large. A double-pole circuit breaker needs 4 to 8 pieces of permanent magnets. , and permanent magnets are generally rare earth materials, which are expensive.

Contents of the invention

Therefore, aiming at the above problems, the present invention proposes a structurally optimized breaking device.

The present invention adopts following technical scheme to realize:

The present invention proposes a breaking device, a breaking device, including a moving contact and a static contact, the moving contact has a movement track relative to the static contact to realize the switching on and off of the breaking device, and also includes An arc extinguishing grid group formed by arranging several arc extinguishing grids, the arc extinguishing grid group is fixed on the side facing the moving track, and also includes a permanent magnet, the permanent magnet is fixed on the On the side of the arc extinguishing grid group facing away from the moving track, the direction from the moving track towards the permanent magnet is defined as the up-down direction, and the orientation of the two magnetic poles of the permanent magnets is arranged along the up-down direction.

Wherein, the breaking device can be single-pole or multi-pole, and each pole of the multi-pole breaking device includes the moving contact, the static contact, the permanent magnet and the arc extinguishing grid. The magnetic poles of the permanent magnets on the adjacent two poles are arranged in opposite polarity.

Wherein, based on manufacturing and installation considerations, in one embodiment, the permanent magnets are strip-shaped, and the permanent magnets are arranged laterally along the width direction of the arc extinguishing grids, or along the arrangement of the arc extinguishing grids Orientation is arranged vertically.

Wherein, in order to make the coverage of the magnetic field larger and the magnetic blowing effect on the forward and reverse currents more even, in one embodiment, the permanent magnets are centrally arranged in the width direction of the arc extinguishing grid.

Wherein, based on manufacturing and installation considerations, in one embodiment, the breaking device further includes a casing above the arc extinguishing grid group facing away from the movement track, and the permanent magnet is fixedly arranged on the casing .

Wherein, based on manufacturing and installation considerations, in one embodiment, the breaking device further includes a permanent magnet fixing part, and the permanent magnet is fixedly arranged on the housing through the permanent magnet fixing part.

Wherein, in order to make the installation of the permanent magnet quicker and easier, in one embodiment, the permanent magnet fixing part is fixedly connected to the housing, and the permanent magnet fixing part has an accommodating shape matching the shape of the permanent magnet. slot, and the permanent magnet is inserted into the receiving slot.

Wherein, in order to simplify the structure and save the manufacturing process, in one embodiment, the casing is fixedly provided with a splitter cone for guiding airflow and exhaust, and the permanent magnet is fixedly arranged on the splitter cone.

Wherein, in order to adapt to applications under small currents, in one embodiment, the breaking device further includes a second permanent magnet and a third permanent magnet, and the second permanent magnet and the third permanent magnet are fixedly arranged on the arc extinguishing Below the grid sheet group and located on the left and right sides of the permanent magnet respectively, the permanent magnet and the second permanent magnet and the third permanent magnet are roughly arranged in the shape of a "pin", and the second permanent magnet and the third permanent magnet A pole relatively close to the lower magnetic pole of the permanent magnet is different from the lower magnetic pole of the permanent magnet, thereby strengthening the magnetic field under the permanent magnet.

Wherein, as a preferred implementation, the breaking device is a frame circuit breaker.

The present invention has the following beneficial effects: the present invention arranges the permanent magnets outside the arc extinguishing chamber, compared with the scheme of arranging the permanent magnets in the arc extinguishing chamber, it can avoid the influence of a large amount of heat when the arc is generated, and will not cause high temperature demagnetization Phenomenon. Moreover, in the present invention, the permanent magnet is arranged on the side of the arc extinguishing grid sheet group facing away from the moving track of the moving contact, so that it can attract the charged particles generated when the arc ablates the contact and rush out of the arc extinguishing chamber, eliminating the need for the next circuit breaker The impact of breaking. In addition, each pole circuit breaker in the present invention only needs one permanent magnet to achieve the non-polarity magnetic blowout effect of the circuit breaker, which greatly reduces the cost, and the installation and arrangement of the permanent magnets are relatively simple, and the manufacturing and assembly process is simple.

Description of drawings

Fig. 1 is the structural diagram of existing circuit breaker with permanent magnet;

Fig. 2 is the schematic diagram that the electric arc of existing circuit breaker with permanent magnet is accelerated by ampere force magnetic blow;

Fig. 3 is an exploded view of the structure of the DC frame circuit breaker in Embodiment 1;

Fig. 4 is a schematic diagram of the moving contact, the static contact, the arc extinguishing grid group and the permanent magnet of the DC frame circuit breaker in the first embodiment (angle one);

Fig. 5 is a schematic diagram (angle 2) of the moving contact, the static contact, the arc extinguishing grid group and the permanent magnet of the DC frame circuit breaker in embodiment 1;

Fig. 6 is the schematic diagram (side view) that electric arc is subjected to Ampere's force by the magnetic field of permanent magnet in embodiment 1;

Fig. 7 is the schematic diagram (overlooking) that electric arc is subjected to Ampere's force by the permanent magnet magnetic field in embodiment 1;

Fig. 8 is the schematic diagram (side view) of the arrangement mode of another kind of optional permanent magnet in embodiment 1;

Fig. 9 is a schematic diagram (top view) of another optional arrangement of permanent magnets in Embodiment 1;

Fig. 10(a) is a schematic diagram of the arc moving towards the arc extinguishing grid group under the two-stage ampere force when the S pole of the permanent magnet is facing downward and the arc current direction is facing inward on the paper;

Figure 10(b) is a schematic diagram of the arc moving towards the arc extinguishing grid group under the two-stage ampere force when the S pole of the permanent magnet is facing down and the arc current direction is facing outwards from the paper;

Figure 10(c) is a schematic diagram of the arc moving towards the arc extinguishing grid group under the two-stage ampere force when the N pole of the permanent magnet is facing downward and the arc current direction is facing inward on the paper;

Figure 10(d) is a schematic diagram of the arc moving towards the arc extinguishing grid group under the two-stage ampere force under the condition that the N pole of the permanent magnet faces downward and the arc current direction faces outwards from the paper;

Fig. 11 is a schematic diagram of the base and permanent magnet fixing parts of the DC frame circuit breaker in Embodiment 1;

Fig. 12 is a schematic diagram of the moving contact, the static contact, the arc extinguishing grid group and the permanent magnet of the DC frame circuit breaker in Embodiment 2 (angle 1);

Fig. 13 is a schematic diagram of the moving contact, the static contact, the arc extinguishing grid group and the permanent magnet of the DC frame circuit breaker in the second embodiment (angle 2);

Fig. 14 is the schematic diagram of the electric arc subjected to the Ampere force under the action of the permanent magnet magnetic field in embodiment 2;

Fig. 15 is a schematic diagram of the arc extinguishing chamber and the first permanent magnet, the second permanent magnet and the third permanent magnet distributed in the shape of "pin" in Embodiment 3.

detailed description

To further illustrate the various embodiments, the present invention is provided with accompanying drawings. These drawings are a part of the disclosure of the present invention, which are mainly used to illustrate the embodiments, and can be combined with related descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, those skilled in the art should understand other possible implementations and advantages of the present invention. Components in the figures are not drawn to scale, and similar component symbols are generally used to denote similar components.

The present invention will be further described in conjunction with the accompanying drawings and specific embodiments.

Referring to Figures 3-5, as a preferred embodiment of the present invention, a circuit breaker is provided, specifically a bipolar DC frame circuit breaker, including a base 10, a side plate 20, a face shield 30, an auxiliary switch 40, Opening and closing electromagnet 50, energy storage motor 60, operating mechanism 70 and arc extinguishing chamber 80, each pole circuit part includes a moving contact 1 and a static contact 2, and the moving contact 1 has a movement relative to the static contact 2. Trajectory 90, according to the motion trajectory 90, the moving contact 1 and the static contact 2 are closed or separated, so as to realize the switching on or off of the circuit breaker. When the moving contact 1 and the static contact 2 are separated, a Arc, for easy understanding, this example schematically shows the arc 5 between the moving contact 1 and the static contact 2 . The arc extinguishing chamber 80 is used to extinguish the arc 5, wherein the arc extinguishing chamber 80 includes an arc extinguishing grid group 3, the arc extinguishing grid group 3 is composed of a plurality of arc extinguishing grids arranged linearly, and the arc extinguishing grid group 3 It is fixedly arranged on the side facing the moving track 90 of the moving contact 1 to extinguish the arc 5 .

This embodiment is also provided with a permanent magnet 4 to realize the arc extinguishing of the magnetic blowing accelerated arc 5. The permanent magnet 4 is arranged on the side of the arc extinguishing grid sheet group 3 facing away from the moving track 90 of the moving contact 1, and the permanent magnet 4 The N poles and S poles of the arc extinguishing grid group 3 are arranged in a direction away from the movement track 90 . For ease of description, the direction from the motion track 90 towards the permanent magnet 4 is defined as the up-down direction, that is, the upper end of the permanent magnet 4 is relatively in the motion track 90, and the motion track 90 is relatively in the lower end of the permanent magnet 4, and the N poles of the permanent magnet 4 and The connection line of the S pole is arranged in the up and down direction, and the two adjacent permanent magnets 4 in the two poles of the bipolar circuit breaker are arranged in opposite polarities, as shown in Figure 6-7, under the arrangement of the permanent magnets 4 in this embodiment The direction of the magnetic field received by the arc 5 under the permanent magnet 4 is generally upward or downward, and the arc under the permanent magnet 4 will be affected by the magnetic field along the width direction of the arc extinguishing grid group 3 based on the influence of the magnetic field of the permanent magnet 4 The ampere force F _a causes the arc 5 to be stretched laterally after entering the arc extinguishing grid set 3 , thereby improving the arc extinguishing effect. Regardless of the current direction of the arc 5, the arc 5 will be stretched laterally after entering the arc extinguishing grid set 3, but the direction of stretching by the magnetic blower is different. Therefore, the circuit breaker itself has no polarity requirements.

In this embodiment, which one of the N pole and the S pole of the permanent magnet 4 is facing up and which one is facing down does not affect the specific magnetic blowing effect. A permanent magnet 4 is arranged opposite to the polarity of the present embodiment.

With the arrangement structure of the permanent magnet 4 in this embodiment, the more important function is that the permanent magnet 4 can also magnetically blow the arc toward the arc extinguishing grid set 3 to push the arc to accelerate into the arc extinguishing grid set 3 . Referring to Fig. 10(a), Fig. 10(b), Fig. 10(c) and Fig. 10(d), the amperes received by the arc under four different arrangement directions of the permanent magnet 4 and the current direction of the arc are respectively shown force direction. It can be seen that in the first stage when the arc is subjected to the ampere force F _a1 (marked by a dotted line in the figure), the arc will be stretched laterally to one side, and in the second stage when the arc is subjected to the ampere force F _a2 , the arc will be inclined Magnetically blow upward toward the direction of the arc extinguishing grid, thereby accelerating arc extinguishing, shortening the arc burning time and reducing the arc burning energy. Regardless of the direction of the current, the effect is similar, and the arc can move toward the arc-extinguishing grid set 3 under the action of the magnetic field of the permanent magnet 4, meeting the requirement of non-polarity of the current.

In this embodiment, the permanent magnet 4 is arranged on the outside of the arc extinguishing chamber. Compared with the scheme in which the permanent magnet is arranged in the arc extinguishing chamber, it can avoid the influence of a large amount of heat when the arc is generated, and will not cause high temperature demagnetization. Covering the heat-insulating shell reduces manufacturing cost and assembly difficulty. Moreover, in this embodiment, the permanent magnet 4 is arranged on the side of the arc extinguishing grid sheet group 3 facing away from the moving track 90 of the moving contact 1, so as to attract the charged particles generated during the arc ablation of the contact to rush out of the arc extinguishing chamber, Eliminate the effect of the next breaking of the circuit breaker. In addition, in this embodiment, only one permanent magnet 4 is needed for each pole circuit breaker to achieve the non-polarity magnetic blowout effect of the circuit breaker, which greatly reduces the cost.

Although this example is illustrated with a two-pole circuit breaker, it is obvious that the permanent magnet 4 can also be applied to a single-pole circuit breaker or a circuit breaker with more poles such as three-poles and four-poles. If it is a multi-pole circuit breaker, then The permanent magnets 4 of adjacent poles need to be arranged with opposite polarities, so as to ensure that the direction of the magnetic field received by the arc 5 under the permanent magnets 4 is generally upward or downward.

Since the one-pole circuit breaker in this embodiment only needs to be provided with a corresponding permanent magnet 4, the installation arrangement of the permanent magnet 4 is also relatively simple. As shown in Figure 3 and Figure 11, the circuit breaker also includes a permanent magnet fixing part 6, and The fixing part 6 is fixedly connected to the side plate 20 , the permanent magnet fixing part 6 has a receiving groove 61 whose shape matches the shape of the permanent magnet 4 , and the permanent magnet 4 is inserted into the receiving groove 61 . Certainly, in other embodiments, other structures of the permanent magnet fixing member may also be used, such as buckle-type and screw-locking permanent magnet fixing members. In addition to using a permanent magnet fixture to fix the permanent magnet, in other embodiments, the permanent magnet 4 can also be directly fixed on the base or the side plate (the base and the side plate are collectively called the circuit breaker housing), for example, in Mounting grooves for mounting the permanent magnet 4 are molded on the base or the side plate. Since the permanent magnet 4 in this embodiment is arranged on the side of the arc extinguishing grid group 3 facing away from the moving track 90 of the moving contact 1, the permanent magnet 4 can be easily installed on the base or the side plate. Further, A splitter cone 101 is also provided on the base or side plate on the side of the arc extinguishing grid group 3 facing away from the moving track 90 of the moving contact 1 to guide the airflow and exhaust. The permanent magnet 4 can be directly installed on the splitter cone 101. To simplify the structure and save the process flow.

Example 2:

As shown in Figures 12-14, this embodiment provides a bipolar DC frame circuit breaker, its structure is similar to that of the circuit breaker in Embodiment 1, the only difference is that the arrangement structure of the permanent magnet 4' in this embodiment is the same as that of The permanent magnet 4 in Embodiment 1 is different. The permanent magnet 4 in the embodiment 1 and the permanent magnet 4' in the present embodiment are elongated structures, the permanent magnet 4 in the embodiment 1 is arranged laterally along the width direction of the arc extinguishing grid, and the permanent magnet 4' in the present embodiment The magnets 4' are longitudinally arranged along the arrangement direction of the arc extinguishing grids.

In other embodiments, the permanent magnet 4' can also be arranged obliquely to the arrangement direction of the arc extinguishing grids. In the arrangement, as long as the N pole and the S pole of the permanent magnet are on the top and the other is on the bottom, and the adjacent poles The magnetic poles of the permanent magnets can be arranged oppositely, because the magnetic field of the permanent magnets is distributed in the entire arc extinguishing space, no matter how the specific placement angle of the permanent magnets is, and how the specific position of the permanent magnets in the width direction of the arc extinguishing grid group 3 is , the obtained magnetic blowing effects are similar, therefore, the arrangement flexibility of the permanent magnet 4' is very high. This embodiment adopts strip-shaped permanent magnets, which are convenient for manufacture and assembly. In fact, permanent magnets of other shapes, such as cylindrical and special-shaped, are also feasible.

As a preferred embodiment, the permanent magnet 4' is centrally arranged in the width direction of the arc extinguishing grid group 3, so that its magnetic field coverage is larger, and regardless of the current polarity, the arc caused by it to the arc extinguishing chamber The effect of magnetic blowing is also more average.

Example 3:

This embodiment proposes further improvements on the basis of Embodiment 1 and Embodiment 2. In Embodiment 1 and Embodiment 2, the magnetic field of a permanent magnet affects a one-pole circuit breaker, and its magnetic force is relatively small, which is suitable for large current specifications In the circuit breaker of (2500A-10KA), this embodiment strengthens the magnetic force to adapt to the circuit breaker of small current specification (2A-2500A).

This embodiment is specifically realized in the following manner: Referring to FIG. 15 , the first permanent magnet 11 is arranged above the arc extinguishing chamber 14 facing away from the moving track of the moving contact. The second permanent magnet 12 and the third permanent magnet 13 distributed on both sides of the first permanent magnet 11 are arranged below the bottom, and the first permanent magnet 11, the second permanent magnet 12 and the third permanent magnet 13 are roughly in the shape of "pin". layout. The magnetic poles of the second permanent magnet 12 and the third permanent magnet 13 are oriented transversely to the width direction of the arc extinguishing grid, and the second permanent magnet 12 and the third permanent magnet 13 are relatively close to the magnetic pole below the first permanent magnet 11 (shown as S pole) One pole of one pole is different from the magnetic pole below the first permanent magnet 11, thereby strengthening the magnetic field below the first permanent magnet 11 under the magnetic field action of the second permanent magnet 12 and the third permanent magnet 13, so that this embodiment 3 can be applied to In the application of small current specifications, it has a greater magnetic blowing effect.

In addition, in this example, compared with the above-mentioned embodiments 1 and 2, the added second permanent magnet 12 and third permanent magnet 13 are closer to the arc, and the anti-demagnetization protection can also be carried out by covering the heat-insulating shell (similar to CN209071258U) , so as to be able to maintain the effect of "strengthening the magnetic field below the first permanent magnet 11 and improving the arc extinguishing capability of the circuit breaker under low current" under long-term use. However, it should be noted that this embodiment 3 mainly relies on the first permanent magnet 11 arranged below the arc extinguishing chamber 14 toward the moving track of the moving contact to achieve the basic functions similar to those of embodiments 1 and 2; therefore, in some considerations In the application of manufacturing cost, whether the function of the second permanent magnet 12 and the third permanent magnet 13 as an auxiliary magnetic field reinforcement can be used for a long time may be a low consideration, so that the use of the corresponding heat insulation shell can be omitted .

The above embodiments are all described by taking the frame circuit breaker as an example, but the arrangement structure of the permanent magnets can also be applied to other breaking devices, such as disconnectors.

Although the invention has been particularly shown and described in connection with preferred embodiments, it will be understood to those skilled in the art that changes in form and details of the invention have been made without departing from the spirit and scope of the invention as defined by the appended claims. The various changes that come out all fall within the scope of protection of the present invention.

Claims (10)

1. The utility model provides a disjunction device, includes moving contact and static contact, the moving contact has a motion track in order to realize the switch-on and the turn-off of disjunction device relatively the static contact, still includes and arranges the arc extinguishing bars group that forms by the several arc extinguishing bars piece, arc extinguishing bars group is fixed to be set up in the one side towards the motion track, its characterized in that: the permanent magnet is fixedly arranged on one side, back to the motion track, of the arc extinguishing grid plate group, the direction from the motion track to the permanent magnet is defined to be the vertical direction, and the permanent magnet is arranged along the vertical direction with the orientation of two magnetic poles of the permanent magnet.

2. A breaking device according to claim 1, characterized in that: the breaking device is provided with a plurality of poles, each pole comprises the moving contact, the fixed contact, the permanent magnets and the arc extinguishing grid piece, and the magnetic poles of the permanent magnets on two adjacent poles are arranged in a polarity opposite mode.

3. A breaking device according to claim 1, characterized in that: the permanent magnets are in a strip shape and are transversely arranged along the width direction of the arc extinguishing grid pieces or are longitudinally arranged along the arrangement direction of the arc extinguishing grid pieces.

4. A breaking device according to claim 3, characterized in that: the permanent magnets are arranged in a centering manner in the width direction of the arc extinguishing grid plate.

5. A breaking device according to claim 1, characterized in that: the permanent magnet arc extinguishing grid group is arranged on the shell, and the permanent magnet arc extinguishing grid group is arranged on the shell.

6. A breaking device according to claim 5, characterized in that: the permanent magnet fixing piece is arranged on the shell and is used for fixing the permanent magnet on the shell.

7. A breaking device according to claim 6, characterized in that: the permanent magnet fixing piece is fixedly connected to the shell and provided with an accommodating groove matched with the shape of the permanent magnet, and the permanent magnet is inserted into the accommodating groove.

8. A breaking device according to claim 5, characterized in that: a splitter cone for guiding airflow exhaust is fixedly arranged on the shell, and the permanent magnet is fixedly arranged on the splitter cone of the shell.

9. A breaking device according to claim 1, characterized in that: still include second permanent magnet and third permanent magnet, second permanent magnet and third permanent magnet are fixed to be set up arc extinguishing bars group below and be located respectively the left and right sides of permanent magnet, the permanent magnet approximately is "article" style of calligraphy with second permanent magnet and third permanent magnet and arranges, second permanent magnet and third permanent magnet are close to relatively a utmost point of permanent magnet below magnetic pole with the below magnetic pole of permanent magnet is different, thereby strengthens the magnetic field of permanent magnet below.

10. A breaking device according to any of claims 1-9, characterized in that: the breaking device is a frame circuit breaker.

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