阅读说明：本技术 一种直流过流脱扣装置 (Direct current overcurrent tripping device ) 是由 韩伟 朱忠建 邱中军 戴罡 孟凡非 葛飞 衣陈晨 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种直流过流脱扣装置,包括导磁框、导磁块、主电路、弹簧、弹簧固定轴,导磁块配合安装于导磁框的缺口中,主电路的外部设置有抵触块,弹簧固定轴的两端分别与导磁块和抵触块衔接,弹簧套设于弹簧固定轴外侧；导磁框设置有导磁框左上端面、导磁框右上端面、导磁框左下端面、导磁框右水平端面；导磁块设置有导磁块左上端面、导磁块右上端面、导磁块左下端面、导磁块右下端面、导磁块左水平端面、导磁块右水平端面。采用导磁框、导磁块、主电路、弹簧、弹簧固定轴的配合进行运作,脱扣速度快,动作可靠,体积紧凑的双向过流脱扣装置,同时防止脱扣装置在小电流情况下误动作,大幅提高直流断路器的动作灵敏度和可靠性。(The invention discloses a direct-current overcurrent tripping device which comprises a magnetic conduction frame, a magnetic conduction block, a main circuit, a spring and a spring fixing shaft, wherein the magnetic conduction block is arranged in a notch of the magnetic conduction frame in a matching way; the magnetic conduction frame is provided with a left upper end surface of the magnetic conduction frame, a right upper end surface of the magnetic conduction frame, a left lower end surface of the magnetic conduction frame and a right horizontal end surface of the magnetic conduction frame; the magnetic conduction block is provided with a left upper end face of the magnetic conduction block, a right upper end face of the magnetic conduction block, a left lower end face of the magnetic conduction block, a right lower end face of the magnetic conduction block, a left horizontal end face of the magnetic conduction block and a right horizontal end face of the magnetic conduction block. The bidirectional overcurrent tripping device has the advantages that the bidirectional overcurrent tripping device operates by matching the magnetic conduction frame, the magnetic conduction block, the main circuit, the spring and the spring fixing shaft, is high in tripping speed, reliable in action and compact in size, meanwhile, the tripping device is prevented from misoperation under the condition of low current, and the action sensitivity and reliability of the direct current circuit breaker are greatly improved.)

1. The utility model provides a direct current overflows trip gear, includes magnetic conduction frame, magnetic conduction piece, main circuit, spring fixed axle, its characterized in that:

the magnetic conduction block is arranged in the notch of the magnetic conduction frame in a matching mode, the outside of the main circuit is provided with a contact block, two ends of the spring fixing shaft are respectively connected with the magnetic conduction block and the contact block, and the spring is sleeved on the outer side of the spring fixing shaft;

the magnetic conduction frame is provided with a left upper end surface of the magnetic conduction frame, a right upper end surface of the magnetic conduction frame, a left lower end surface of the magnetic conduction frame, a right lower end surface of the magnetic conduction frame, a left horizontal end surface of the magnetic conduction frame and a right horizontal end surface of the magnetic conduction frame; the magnetic conduction block is provided with a left upper end face of the magnetic conduction block corresponding to the left upper end face of the magnetic conduction frame, a right upper end face of the magnetic conduction block corresponding to the right upper end face of the magnetic conduction frame, a left lower end face of the magnetic conduction block corresponding to the left lower end face of the magnetic conduction frame, a right lower end face of the magnetic conduction block corresponding to the right lower end face of the magnetic conduction frame, a left horizontal end face of the magnetic conduction block corresponding to the left horizontal end face of the magnetic conduction frame, and a right horizontal end face of the magnetic conduction block corresponding to the right horizontal end face of the magnetic conduction frame.

2. The dc overcurrent trip unit of claim 1, wherein: an upper side gap is formed between the left upper end face of the magnetic conduction frame and the right upper end face of the magnetic conduction frame, and a lower side gap is formed between the left lower end face of the magnetic conduction frame and the right lower end face of the magnetic conduction frame.

3. The dc overcurrent trip unit of claim 1, wherein: the magnetic conduction block can be provided with a magnetic conduction block left concave platform and a magnetic conduction block right concave platform which are used for adjusting the lap joint area of the horizontal end faces of the magnetic conduction frame and the magnetic conduction block.

4. The dc overcurrent trip unit of claim 1, wherein: the magnetic conduction frame is formed by splicing a plurality of magnetic conduction materials.

5. The dc overcurrent trip unit of claim 4, wherein: magnetic conduction frame includes two vertical strips of lateral part, upside cooperation strip, downside cooperation strip, the both ends of upside cooperation strip are contradicted respectively in the upper end of two vertical strips of lateral part, the both ends of downside cooperation strip are contradicted respectively in the lower extreme of two vertical strips of lateral part, be provided with the breach on the upside cooperation strip.

6. The dc overcurrent trip unit of claim 1, wherein: the magnetic conduction frame is formed by horizontally stacking a plurality of layers of magnetic conduction sheets, and the thickness of each magnetic conduction sheet is 0.5mm or 1 mm.

7. The dc overcurrent trip unit of claim 1, wherein: the magnetic conduction block is formed by horizontally stacking a plurality of layers of magnetic conduction sheets, and the thickness of each magnetic conduction sheet is 0.5mm or 1 mm.

8. The dc overcurrent trip unit of claim 1, wherein: the left horizontal end face of the magnetic conduction frame and the right horizontal end face of the magnetic conduction frame are positioned on the same horizontal plane.

9. The dc overcurrent trip unit of claim 8, wherein: the left horizontal end face of the magnetic conduction frame is parallel to the surface of the contact block.

10. The dc overcurrent trip unit of claim 1, wherein: the extending direction of the spring fixing shaft is perpendicular to the left horizontal end face of the magnetic conduction frame.

Technical Field

The invention relates to the field of direct current quick circuit breakers, in particular to a direct current overcurrent tripping device.

Background

At present, urban rail transit, particularly subways, has become an important traffic tool in cities, and the characteristics of no pollution, convenience and quickness are deeply loved by people. In order to ensure the normal running and the travelling comfort of the metro vehicle, the high-speed circuit breaker used by the metro vehicle is generally a direct-current quick circuit breaker. The direct current quick breaker is used as core protection equipment of a direct current traction power supply system, can quickly cut off the fault current of a loop, and is an important guarantee for the safe operation of the direct current power supply system. Compared with an alternating current system, the direct current system is more difficult to switch on and off because the direct current system does not have a natural zero crossing point, so that a safe and reliable direct current overcurrent tripping device is needed, and the direct current breaker can rapidly switch off short-circuit current under the condition of loop fault; meanwhile, under the normal working condition of the direct current circuit breaker, namely when the current of the main loop is at the rated current or below, the tripping device prevents misoperation, and the safe and reliable operation of the direct current traction power supply system of the urban rail transit is ensured.

An authorized bulletin No. CN210092017U discloses an overcurrent high-speed trip device for a dc circuit breaker, which comprises a magnetic conduction frame, a triangular opening is arranged at the middle position of the top of the magnetic conduction frame, an aluminum square tube is fixed at the bottom of the magnetic conduction frame, a magnetic conduction block is arranged in the triangular opening, the aluminum square tube penetrates through the lower part of the magnetic conduction frame and extends into the magnetic conduction frame, and a guide block is sleeved at the upper end of the aluminum square tube. The tripping device can conveniently adjust the limit value of the overload current of the main circuit of the circuit breaker. However, the top of the magnetic conduction frame of the tripping device is a triangular opening, the corresponding magnetic conduction block is triangular, and when the current of the main loop is lower than the rated current, the magnetic conduction block can generate counter force against a spring under the action of electromagnetic force, so that the spring holding force of the tripping mechanism is reduced, the tripping mechanism is easy to malfunction under the condition of low current, and meanwhile, the magnetic conduction block is large in size, so that the reaction speed of the tripping device can be reduced.

The circuit breaker tripping device disclosed in the publication number of US8497750B2 includes a magnetic conduction frame through which current can pass and a magnetic conduction block which can move in the magnetic conduction frame. When the breaker is in a closing state, the magnetic conduction block is at the first position and can move in the notch of the magnetic conduction frame. And when the breaker is opened, the magnetic conduction block moves to the second position. The tripping device utilizes the magnetic flux generated by the current in the magnetic conduction frame to make the magnetic conduction block move between two positions. The tripping device is characterized in that a boss is additionally arranged below the magnetic conduction block in order to enable the magnetic conduction block to generate a retaining force under the condition of low current, so that the volume of the magnetic conduction block is increased, the mass of the magnetic conduction block is increased, and the action speed of the tripping device is reduced.

The above patent documents disclose that the conventional dc overcurrent trip device has the following drawbacks:

most of the technical schemes of the direct current overcurrent tripping devices at the present stage have the defects of large volume, slow tripping speed and easy generation of misoperation under the condition of low current.

Disclosure of Invention

In order to overcome the defects of the prior art, one of the objectives of the present invention is to provide a dc overcurrent tripping device, which can solve the problems of large volume, slow tripping speed and easy generation of malfunction.

One of the purposes of the invention is realized by adopting the following technical scheme:

a direct current overcurrent tripping device comprises a magnetic conduction frame, a magnetic conduction block, a main circuit, a spring and a spring fixing shaft, wherein the magnetic conduction block is installed in a notch of the magnetic conduction frame in a matching mode, a contact block is arranged outside the main circuit, two ends of the spring fixing shaft are respectively connected with the magnetic conduction block and the contact block, and the spring is sleeved on the outer side of the spring fixing shaft; the magnetic conduction frame is provided with a left upper end surface of the magnetic conduction frame, a right upper end surface of the magnetic conduction frame, a left lower end surface of the magnetic conduction frame, a right lower end surface of the magnetic conduction frame, a left horizontal end surface of the magnetic conduction frame and a right horizontal end surface of the magnetic conduction frame; the magnetic conduction block is provided with a left upper end face of the magnetic conduction block corresponding to the left upper end face of the magnetic conduction frame, a right upper end face of the magnetic conduction block corresponding to the right upper end face of the magnetic conduction frame, a left lower end face of the magnetic conduction block corresponding to the left lower end face of the magnetic conduction frame, a right lower end face of the magnetic conduction block corresponding to the right lower end face of the magnetic conduction frame, a left horizontal end face of the magnetic conduction block corresponding to the left horizontal end face of the magnetic conduction frame, and a right horizontal end face of the magnetic conduction block corresponding to the right horizontal end face of the magnetic conduction frame.

Furthermore, an upper side gap is formed between the upper left end face of the magnetic conduction frame and the upper right end face of the magnetic conduction frame, and a lower side gap is formed between the lower left end face of the magnetic conduction frame and the lower right end face of the magnetic conduction frame.

Furthermore, the magnetic conduction block can be provided with a left magnetic conduction block concave platform and a right magnetic conduction block concave platform which are used for adjusting the lap joint area of the horizontal end faces of the magnetic conduction frame and the magnetic conduction block.

Furthermore, the magnetic conduction frame is formed by splicing a plurality of magnetic conduction materials.

Further, magnetic conduction frame includes two vertical strips of lateral part, upside cooperation strip, downside cooperation strip, the both ends of upside cooperation strip are contradicted respectively in the upper end of two vertical strips of lateral part, the both ends of downside cooperation strip are contradicted respectively in the lower extreme of two vertical strips of lateral part, be provided with the breach on the upside cooperation strip.

Furthermore, the magnetic conduction frame is formed by horizontally stacking a plurality of layers of magnetic conduction sheets, and the thickness of each magnetic conduction sheet is 0.5mm or 1 mm.

Furthermore, the magnetic conduction block is formed by horizontally stacking a plurality of layers of magnetic conduction sheets, and the thickness of each magnetic conduction sheet is 0.5mm or 1 mm.

Furthermore, the left horizontal end face of the magnetic conduction frame and the right horizontal end face of the magnetic conduction frame are positioned on the same horizontal plane.

Furthermore, the left horizontal end face of the magnetic conduction frame is parallel to the surface of the contact block.

Furthermore, the extending direction of the spring fixing shaft is perpendicular to the left horizontal end face of the magnetic conduction frame.

Compared with the prior art, the invention has the beneficial effects that:

the magnetic conduction block is arranged in the notch of the magnetic conduction frame in a matching mode, the outside of the main circuit is provided with a contact block, two ends of the spring fixing shaft are respectively connected with the magnetic conduction block and the contact block, and the spring is sleeved on the outer side of the spring fixing shaft; the magnetic conduction frame is provided with a left upper end surface of the magnetic conduction frame, a right upper end surface of the magnetic conduction frame, a left lower end surface of the magnetic conduction frame, a right lower end surface of the magnetic conduction frame, a left horizontal end surface of the magnetic conduction frame and a right horizontal end surface of the magnetic conduction frame; the magnetic conduction block is provided with a left upper end face of the magnetic conduction block corresponding to the left upper end face of the magnetic conduction frame, a right upper end face of the magnetic conduction block corresponding to the right upper end face of the magnetic conduction frame, a left lower end face of the magnetic conduction block corresponding to the left lower end face of the magnetic conduction frame, a right lower end face of the magnetic conduction block corresponding to the right lower end face of the magnetic conduction frame, a left horizontal end face of the magnetic conduction block corresponding to the left horizontal end face of the magnetic conduction frame, and a right horizontal end face of the magnetic conduction block corresponding to the right horizontal end face of the magnetic conduction frame. The bidirectional overcurrent tripping device has the advantages that the bidirectional overcurrent tripping device operates by matching the magnetic conduction frame, the magnetic conduction block, the main circuit, the spring and the spring fixing shaft, is high in tripping speed, reliable in action and compact in size, meanwhile, the tripping device is prevented from misoperation under the condition of low current, and the action sensitivity and reliability of the direct current circuit breaker are greatly improved.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.

Drawings

FIG. 1 is a perspective view of a DC overcurrent trip device according to a preferred embodiment of the present invention;

FIG. 2 is a structural diagram of a magnetic frame of the DC overcurrent trip device shown in FIG. 1;

FIG. 3 is a structural diagram of a magnetic block in the DC overcurrent tripping device shown in FIG. 1;

FIG. 4 is a schematic diagram of the main circuit flowing a rising current less than a rated current;

FIG. 5 is a schematic diagram of the main circuit flowing a rising current greater than a rated current;

fig. 6 is a schematic view of the magnetic conductive block of the dc overcurrent trip device shown in fig. 1 reaching a lower position.

In the figure: 1. a magnetic conduction frame; 2. a magnetic conduction block; 3. a main circuit; 4. a spring; 5. a spring fixing shaft; 11. the left upper end surface of the magnetic conduction frame; 12. the right upper end surface of the magnetic conduction frame; 13. the left lower end surface of the magnetic conduction frame; 14. the right lower end surface of the magnetic conduction frame; 15. the left horizontal end face of the magnetic conduction frame; 16. the right horizontal end surface of the magnetic conduction frame; 21. the upper left end surface of the magnetic conduction block; 22. the right upper end surface of the magnetic conduction block; 23. the left lower end surface of the magnetic conduction block; 24. the right lower end surface of the magnetic conduction block; 25. the left horizontal end face of the magnetic conduction block; 26. the right horizontal end face of the magnetic conduction block; 27. a left concave platform of the magnetic conduction block; 28. magnetic conduction piece right concave station.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1-6, a dc overcurrent trip device includes a magnetic conduction frame 1, a magnetic conduction block 2, a main circuit 3, a spring 4, and a spring fixing shaft 5, wherein the magnetic conduction block 2 is installed in a notch of the magnetic conduction frame 1 in a matching manner, a contact block is arranged outside the main circuit 3, two ends of the spring fixing shaft 5 are respectively connected with the magnetic conduction block 2 and the contact block, and the spring 4 is sleeved outside the spring fixing shaft 5; the magnetic conduction frame 1 is provided with a left upper end surface 11 of the magnetic conduction frame, a right upper end surface 12 of the magnetic conduction frame, a left lower end surface 13 of the magnetic conduction frame, a right lower end surface 14 of the magnetic conduction frame, a left horizontal end surface 15 of the magnetic conduction frame and a right horizontal end surface 16 of the magnetic conduction frame; the magnetic conduction block 2 is provided with a magnetic conduction block left upper end face 21 corresponding to the magnetic conduction frame left upper end face 11, a magnetic conduction block right upper end face 22 corresponding to the magnetic conduction frame right upper end face 12, a magnetic conduction block left lower end face 23 corresponding to the magnetic conduction frame left lower end face 13, a magnetic conduction block right lower end face 24 corresponding to the magnetic conduction frame right lower end face 14, a magnetic conduction block left horizontal end face 25 corresponding to the magnetic conduction frame left horizontal end face 15, and a magnetic conduction block right horizontal end face 26 corresponding to the magnetic conduction frame right horizontal end face 16. The bidirectional overcurrent tripping device is high in tripping speed, reliable in action and compact in size, meanwhile, the tripping device is prevented from misoperation under the condition of low current, and the action sensitivity and reliability of the direct current circuit breaker are greatly improved.

Preferably, the current in the main circuit 1 generates magnetic flux in the dc overcurrent tripping device in both forward and reverse directions, so that the dc overcurrent tripping device operates normally, and thus the dc overcurrent tripping device is a bidirectional tripping device.

Preferably, an upper side gap is formed between the upper left end face 11 of the magnetic conduction frame and the upper right end face 12 of the magnetic conduction frame, and a lower side gap is formed between the lower left end face 13 of the magnetic conduction frame and the lower right end face 14 of the magnetic conduction frame.

Preferably, the magnetic conduction block 2 may be provided with a magnetic conduction block left concave platform 27 and a magnetic conduction block right concave platform 28 for adjusting the overlapping area of the horizontal end faces of the magnetic conduction frame 1 and the magnetic conduction block 2. By adjusting the lengths of the left magnetic block concave 27 and the right magnetic block concave 28, the overlapping area of the horizontal end surfaces of the magnetic conduction frame 1 and the magnetic conduction block 2, namely, between the left horizontal end surface 25 of the magnetic conduction block and the left horizontal end surface 15 of the magnetic conduction frame, and between the right horizontal end surface 26 of the magnetic conduction block and the right horizontal end surface 16 of the magnetic conduction frame, the critical current value when the magnetic flux Φ a is saturated, namely, the minimum critical current value of the action of the tripping device is adjusted, and the action sensitivity of the tripping device is improved.

Preferably, the magnetic conduction frame 1 is formed by splicing a plurality of magnetic conduction materials. In one embodiment, the magnetic conduction frame 1 includes two lateral vertical bars, an upper side matching bar and a lower side matching bar, two ends of the upper side matching bar respectively abut against the upper ends of the two lateral vertical bars, two ends of the lower side matching bar respectively abut against the lower ends of the two lateral vertical bars, and a notch is formed in the upper side matching bar.

Specifically, the magnetic conduction frame 1 is formed by horizontally stacking a plurality of layers of magnetic conduction sheets, and the thickness of each magnetic conduction sheet is 0.5mm or 1 mm. The magnetic conduction block 2 is formed by horizontally stacking a plurality of layers of magnetic conduction sheets, and the thickness of each magnetic conduction sheet is 0.5mm or 1 mm. The magnetic conduction frame 1 is convenient to process and manufacture due to the splicing arrangement of the magnetic conduction frame 1; the gap between the magnetic conductive materials can be adjusted to influence the magnetic field intensity formed by the current in the main circuit 3 in the loop formed by the magnetic conductive frame 1 and the magnetic conductive block 2, thereby changing the critical action current value of the direct current overcurrent tripping device.

Preferably, the left horizontal end face 15 of the magnetic conduction frame and the right horizontal end face 16 of the magnetic conduction frame are on the same horizontal plane. The left horizontal end face 15 of the magnetic conduction frame is parallel to the surface of the contact block. The extending direction of the spring fixing shaft 5 is perpendicular to the left horizontal end face 15 of the magnetic conduction frame.

Preferably, the value of the spring force of the spring 4 is adjusted to adjust the value of the critical operating current flowing through the dc release device. The magnetic conduction block 2 can move from bottom to top by changing the directions of the inclined end surfaces of the magnetic conduction block 2 and the magnetic conduction frame 1.

The specific location specification is: the magnetic conduction block 2 is positioned in the gap of the magnetic conduction frame 1 and can move up and down in the gap to form a loop with the magnetic conduction frame 1. The main circuit 3 vertically passes through a loop formed by the magnetic conduction block 2 and the magnetic conduction frame 1. A spring fixing shaft 5 is fixed on the magnetic conduction frame 1, and a spring 4 is fixed on the spring fixing shaft 5. The spring 4 and the spring fixing shaft 5 are both positioned below the magnetic conduction block 2. The upper left side of the magnetic conduction frame 1 comprises a magnetic conduction frame left upper end surface 11 and a magnetic conduction frame left lower end surface 13 which are in the same direction, and a horizontal magnetic conduction frame left horizontal end surface 15 is arranged between the magnetic conduction frame left upper end surface 11 and the magnetic conduction frame left lower end surface 13. The right side comprises a right upper end face 12 of the magnetic conduction frame and a right lower end face 14 of the magnetic conduction frame which are in the same direction, and a horizontal right horizontal end face 16 of the magnetic conduction frame is arranged between the right upper end face 12 of the magnetic conduction frame and the right lower end face 14 of the magnetic conduction frame. The magnetic conduction block 2 is composed of an upper triangle and a lower triangle, the left side of the magnetic conduction block comprises a left upper end surface 21 and a left lower end surface 23 of the magnetic conduction block, the left upper end surface 21 and the left lower end surface 23 of the magnetic conduction block are in the same direction, a horizontal left horizontal end surface 25 of the magnetic conduction block is arranged between the left upper end surface 21 and the left lower end surface 23 of the magnetic conduction block, and a left concave platform 27 of the magnetic conduction block can be arranged on the left horizontal end surface 25 of the magnetic conduction block. The right side comprises a right upper end face 22 and a right lower end face 24 of the magnetic conducting block, which have the same direction, a horizontal right horizontal end face 26 of the magnetic conducting block is arranged between the right upper end face 22 and the right lower end face 24 of the magnetic conducting block, and a right concave platform 28 of the magnetic conducting block can be arranged on the right horizontal end face 26 of the magnetic conducting block.

When the direct current breaker is switched on, the magnetic conduction block 2 is located at the upper position. When the current flowing in the main circuit 3 rapidly rises, a magnetic field is formed in a loop formed by the magnetic conduction frame 1 and the magnetic conduction block 2, and a large magnetic flux is generated in the magnetic circuit, so that a strong electromagnetic attraction force is generated between the end surfaces of the magnetic conduction frame 1 and the magnetic conduction block 2. When the rising current flowing through the main circuit 3 is smaller than the rated current, an electromagnetic attraction force is generated between the horizontal end faces of the magnetic conduction frame 1 and the magnetic conduction block 2, the direction of the electromagnetic attraction force is the same as the elastic direction of the spring, so that the magnetic conduction block 2 is kept at the upper position, and the magnetic conduction block 2 is prevented from generating misoperation. When the rising current flowing through the main circuit 3 is larger than the rated current, the magnetic flux between the horizontal end surfaces of the magnetic conduction frame 1 and the magnetic conduction block 2 is saturated, electromagnetic attraction is generated between the inclined end surfaces of the magnetic conduction frame 1 and the magnetic conduction block 2, the direction is opposite to the elastic force direction of the spring, when the electromagnetic attraction value is larger than the sum of the counter force of the spring and the mechanism resistance, the magnetic conduction block 2 moves downwards, and when the magnetic conduction block 2 reaches the lower position, the breaker is opened, and the tripping action is completed.

There are three states of actual operation:

first, in an initial state, that is, when there is no current rising in the main circuit 3, as shown in fig. 1, when there is no current rising in the main circuit 3, the spring 4 fixed on the spring fixing shaft 5 applies an upward thrust to the magnetic conductive block 2, so that the left horizontal end surface 25 and the right horizontal end surface 26 of the magnetic conductive block are in contact with the left horizontal end surface 15 and the right horizontal end surface 16 of the magnetic conductive frame. And a large air gap exists between the left upper end surface 21 of the magnetic conduction block, the right upper end surface 22 of the magnetic conduction block, the left lower end surface 23 of the magnetic conduction block, the right lower end surface 24 of the magnetic conduction block on the magnetic conduction block 2, and the left upper end surface 11 of the magnetic conduction frame, the right upper end surface 12 of the magnetic conduction frame, the left lower end surface 13 of the magnetic conduction frame and the right lower end surface 14 of the magnetic conduction frame on the magnetic conduction frame 1. At this time, the magnetic conduction block 2 is positioned above the notch of the magnetic conduction frame 1, and the position is the initial position of the magnetic conduction block 2.

Secondly, the rising current flowing through the main circuit 3 is smaller than the rated current, as shown in fig. 4, when the current flows through the main circuit 3, a magnetic field is formed in a loop formed by the magnetic conduction frame 1 and the magnetic conduction block 2. Because the left horizontal end face 25 and the right horizontal end face 26 of the magnetic conduction block are in lap joint with the left horizontal end face 15 and the right horizontal end face 16 of the magnetic conduction frame, the magnetic field generates a magnetic flux Φ a in a magnetic circuit formed by the right horizontal end face 16 of the magnetic conduction frame, the right horizontal end face 26 of the magnetic conduction block, the left horizontal end face 25 of the magnetic conduction block and the left horizontal end face 15 of the magnetic conduction frame, and an upward electromagnetic attraction force is generated between the horizontal end faces of the magnetic conduction frame 1 and the magnetic conduction block 2. Since the rising current flowing through the main circuit 3 is smaller than the rated current and the magnetic flux Φ a in the magnetic circuit is not saturated, a downward electromagnetic attraction force is not generated between the inclined end surfaces of the magnetic conductive frame 1 and the magnetic conductive block 2. The direction of upward electromagnetic attraction generated between the horizontal end surfaces of the magnetic conduction frame 1 and the magnetic conduction block 2 is the same as the elastic force direction of the spring, so that resultant force for keeping the magnetic conduction block 2 at the initial position is formed, and the magnetic conduction block 2 is prevented from being mistakenly operated when the rising current is smaller than the rated current.

And thirdly, the rising current flowing through the main circuit 3 is larger than the rated current, and when the rising current flowing through the main circuit 3 is larger than the rated current, a strong magnetic field is formed in a loop formed by the magnetic conduction frame 1 and the magnetic conduction block 2. The magnetic field generates a magnetic flux Φ a in a magnetic circuit of the right horizontal end face 16 of the magnetic conduction frame, the right horizontal end face 26 of the magnetic conduction block, the left horizontal end face 25 of the magnetic conduction block, and the left horizontal end face 15 of the magnetic conduction frame. Because the lap joint area between the horizontal end surfaces is small, the magnetic flux phi A in the magnetic circuit is saturated, so the magnetic field can generate the magnetic flux phi B in the magnetic circuit of the right upper end surface 12 of the magnetic conduction frame, the right upper end surface 22 of the magnetic conduction block, the left upper end surface 21 of the magnetic conduction block and the left upper end surface 11 of the magnetic conduction frame, and generate the magnetic flux phi C in the magnetic circuit of the right lower end surface 14 of the magnetic conduction frame, the right lower end surface 24 of the magnetic conduction block, the left lower end surface 23 of the magnetic conduction block and the left lower end surface 13 of the magnetic conduction frame. The magnetic flux Φ B and the magnetic flux Φ C generate a downward electromagnetic attraction force between the end faces of the magnetic conductive frame 1 and the magnetic conductive block 2, and the direction of the electromagnetic attraction force is opposite to the direction of the elastic force of the spring. When the electromagnetic attraction force generated by the magnetic flux Φ B and the magnetic flux Φ C exceeds the sum of the electromagnetic attraction force generated by the magnetic flux Φ a, the spring elastic force, and the mechanism resistance, the magnetically conductive block 2 starts to move downward. In the process that the magnetic conduction block 2 moves downwards, the distance between the horizontal end surfaces of the magnetic conduction frame 1 and the magnetic conduction block 2 is increased, the distance between the inclined end surfaces is decreased, so that the electromagnetic attraction force generated by the magnetic flux Φ a is decreased, the electromagnetic attraction force generated by the magnetic flux Φ B and the magnetic flux Φ C is increased, and therefore, the magnetic conduction block 2 can move downwards in an accelerated manner in the process.

After the magnetic conduction block 2 reaches the lower position, the inclined end faces of the magnetic conduction frame 1 and the magnetic conduction block 2 coincide, the left upper end face 11 of the magnetic conduction frame coincides with the left upper end face 21 of the magnetic conduction block, the right upper end face 12 of the magnetic conduction frame coincides with the right upper end face 22 of the magnetic conduction block, the left lower end face 13 of the magnetic conduction frame coincides with the left lower end face 23 of the magnetic conduction block, and the right lower end face 14 of the magnetic conduction frame coincides with the right lower end face 24 of the magnetic conduction block. At this time, an air gap is formed between the horizontal end faces of the magnetic conduction frame 1 and the magnetic conduction block 2, between the left horizontal end face 15 of the magnetic conduction frame and the left horizontal end face 25 of the magnetic conduction block, and between the right horizontal end face 16 of the magnetic conduction frame and the right horizontal end face 26 of the magnetic conduction block, so that the magnetic flux of the magnetic field in the magnetic circuit mainly comprises phi B and phi C, the upward electromagnetic attraction force generated by the magnetic flux phi A disappears, and at this time, the magnetic field completely generates downward electromagnetic attraction force, so that the magnetic conduction block 2 finishes tripping action.

The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.