A protective drop-out fuse

Abstract

The present invention discloses a protective drop-out fuse, which relates to the technical field of drop-out fuses and aims to solve the technical problem that the chemical arc extinguishing method cannot perform arc extinguishing well in some environments. It includes an installation bracket; an insulating support is obliquely arranged at the end of the installation bracket through bolts; a buckling arm is arranged on the top of the insulating support; a rotating shaft connecting arm is arranged at the bottom of the insulating support; a protective fuse tube assembly is arranged on the rotating shaft connecting arm through a rotating fastener; the protective fuse tube assembly includes a fuse tube main body. Based on the magnitude of the current passing value, the present invention generates different current conditions, and through different current conditions, the magnetic induction coil is used to drive the armature to perform different ascending length adjustment operations, so as to cause the multi-stage arc extinguishing structure to perform arc extinguishing work in different states, and the protective fuse tube assembly is effectively maintained to perform arc extinguishing work by mechanical means, effectively reducing the insufficient stability of chemical arc extinguishing.

Description

Technical Field

[0001] The present invention relates to the technical field of drop fuses, and more specifically, to a protective drop fuse. Background Art

[0002] Drop fuses are generally arranged in high-voltage distribution lines. When the drop fuse is operating normally, the fuse tube forms a closed position by means of the tension of the fuse wire. When a fault occurs in the system, the fault current causes the fuse wire to melt quickly. After the fuse wire melts, the lower static contact loses tension and turns downwards, releasing the fuse tube by the tightening mechanism, and the fuse tube drops to form an obvious open position.

[0003] Existing protective drop fuses decompose a large amount of non-conductive gases such as carbon dioxide and nitrogen at high arc temperatures by arranging an inner layer of vulcanized fiber tube inside to form a longitudinal high-pressure air flow to blow out the arc. In high-altitude areas, the air pressure is relatively low, which may lead to insufficient gas pressure and ineffective arc blowing; in a dirty environment, the surface of the fuse tube may be contaminated, affecting the gas discharge path and the situation where insufficient non-conductive gases such as carbon dioxide and nitrogen are decomposed in a corrosive environment, resulting in arc extinguishing failure. Therefore, how to propose a protective drop fuse with mechanical arc extinguishing to reduce the damage or explosion of equipment caused by continuous combustion under current conditions. In view of this, we propose a protective drop fuse. Summary of the Invention

[0004] The purpose of the present invention is to provide a protective drop fuse to solve the technical problem that the chemical arc extinguishing method cannot perform arc extinguishing well in some environments.

[0005] To solve the above technical problems, the present invention provides the following technical solution: A protective drop fuse, including an installation bracket; an insulating support is arranged obliquely at the end of the installation bracket through bolts; a buckling arm is arranged on the top of the insulating support; a rotating shaft connecting arm is arranged at the bottom of the insulating support; a protective fuse tube assembly is arranged on the rotating shaft connecting arm through a rotating fastener; the protective fuse tube assembly includes a fuse tube main body; the fuse tube main body is rotatably arranged at the rotating end of the rotating shaft connecting arm through a rotating fastener; wherein, a restoring cavity and an arc extinguishing cavity are sequentially arranged in the fuse tube main body from top to bottom; a movable contact is buckled and arranged at the top of the fuse tube main body; wherein, at least one magnetic induction coil is fixedly arranged at the bottom of the movable contact relative to the inside of the fuse tube main body; wherein, the connecting end of the movable contact and the magnetic induction coil is fixedly connected; an armature is arranged through the inside of the fuse tube main body; an auxiliary supporting seat is fixedly arranged at the top of the armature; a multi-stage restoring spring is arranged on the top of the auxiliary supporting seat; a multi-stage arc extinguishing structure is arranged at the bottom of the armature; wherein, the multi-stage arc extinguishing structure is a telescopic mechanism.

[0006] Based on the magnitude of the current passing through, the present invention generates different current conditions. Through different current conditions, a magnetic induction coil is used to drive the armature to perform different upward length adjustment operations, so as to cause the multi-stage arc extinguishing structure to perform arc extinguishing work in different states. Moreover, the arc extinguishing work of the protective fuse tube assembly is effectively maintained by mechanical means, effectively reducing the insufficient stability of chemical arc extinguishing.

[0007] Preferably, a connecting sliding seat for basic support and guidance of the armature is arranged between the fuse tube main body and the restoring force cavity and the arc extinguishing cavity; a fuse buckle for connecting with the fuse is arranged at the output end of the magnetic induction coil, and the input end of the magnetic induction coil is fixedly connected with the moving contact; a guiding buckle is arranged at the bottom of the armature.

[0008] Preferably, the auxiliary supporting seat is in a "U" shape, and the top of the multi-stage restoring force spring is fixedly connected with the fuse tube main body, and the multi-stage restoring force spring is in a "hourglass" shape.

[0009] Preferably, the multi-stage arc extinguishing structure includes a main driving hollow shaft arranged at the axis position of the fuse tube main body; an auxiliary buckle adapted to the guiding buckle is arranged at the top of the main driving hollow shaft; and a dividing groove is arranged at the top of the main driving hollow shaft.

[0010] Preferably, a multi-stage drawing component is arranged outside the main driving hollow shaft; the multi-stage drawing component includes a plurality of partition grid ring blocks arranged concentrically; receiving grooves are arranged on both sides of the partition grid ring block; sliding shafts are arranged in the receiving grooves; springs are arranged on both the upper and lower sides of the sliding shaft; a force limiting block is arranged between the two springs; wherein, the cross section of the partition grid ring block is in a "[" shape.

[0011] Preferably, for relatively small current conditions of the moving contact, the magnetic induction coil is energized and magnetically actuated to drive the armature to move upward, and the multi-stage restoring force spring moves through a relatively small compression path, causing the armature to upwardly drag the main driving hollow shaft through the guiding buckle, causing the plurality of partition grid ring blocks to be stretched and separated, forming an axially stretched and separated structure for generating an arc under relatively small current conditions.

[0012] Preferably, for relatively large current conditions of the moving contact, the magnetic induction coil is energized and magnetically actuated to drive the armature to move upward, and the multi-stage restoring force spring moves through a relatively large compression path, causing the armature to upwardly drag the main driving hollow shaft through the guiding buckle, and the lifting distance of the main driving hollow shaft is greater than the maximum stretching distance of the multi-stage drawing component, causing the guiding buckle to be separated from the auxiliary buckle. With the arrangement of the springs, the plurality of partition grid ring blocks are adjusted by upward and downward restoring force drawing, forming an axially multi-stage partition structure for generating an arc under relatively large current conditions.

[0013] A method for using a protective drop-out fuse, comprising the following steps:

[0014] S100. Fuse installation: Install and connect the fuse to the fuse buckle through a fastener, and install the other end of the fuse to the rotating shaft connecting arm connecting component;

[0015] S200. Closing treatment: Use a tool to push the ring buckle on the side of the protective fuse tube assembly to rotate, causing the movable contact to be buckled with the fixed contact;

[0016]

[0017] S300. Arc extinguishing treatment:

[0018] If a small current condition occurs; based on the movable contact for the small current condition, causing the fuse to melt and generate an arc. At the same time, compared with the conventional current, the current increases in the small current condition, causing the magnetic induction coil to drive the main drive hollow shaft to lift through the armature, and the multi-stage restoring spring moves through a relatively small compression path. The armature lift drives the main drive hollow shaft and multiple partition grid ring blocks to stretch, so as to radially separate the arc;

[0019] If a large current condition occurs; based on the movable contact for the large current condition, causing the fuse to melt and generate an arc. At the same time, compared with the conventional current, the current increases in the large current condition, causing the magnetic induction coil to drive the main drive hollow shaft to lift through the armature, and the multi-stage restoring spring moves through a relatively large compression path. The armature lift drives the main drive hollow shaft and multiple partition grid ring blocks to stretch fully, causing the guide buckle to separate from the auxiliary buckle. Based on the action of gravity and the elastic restoring force of the spring, the multiple partition grid ring blocks perform up and down restoring pulling adjustment to continuously extinguish the arc generated in the large current condition for a short time.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. Based on the magnitude of the current passing through, the present invention generates different current conditions, and through different current conditions, the magnetic induction coil is used to drive the armature to perform different ascending length adjustment operations, so as to cause the multi-stage arc extinguishing structure to perform arc extinguishing work in different states. And through mechanical means, the protective fuse tube assembly is effectively maintained to perform arc extinguishing work, effectively reducing the insufficient stability of chemical arc extinguishing.

[0022] ​2. The present invention divides the arc extinguishing cavity into multiple cavities at the axial position through an auxiliary supporting seat in the shape of a "凵" character, and forms a basic arc extinguishing work through the separation; and the present invention can effectively distinguish between small or large current conditions through the arrangement of a multi-stage restoring spring in the shape of an "hourglass". Based on the "hourglass" shaped multi-stage restoring spring, the armature rising power can only perform basic compression work under small current conditions, and the armature rising power needs to be synchronized under large current conditions, and the multi-stage restoring spring is negatively compressed. This method effectively controls the armature rising adjustment required under large current conditions, reduces the false triggering of specified numerical currents, and eliminates unnecessary maintenance work.

[0023] 3. The present invention forms a basic connection state and an excessive separation state through the elastic buckle setting of the guide buckle head and the auxiliary buckle head. In the basic connection state, the guide buckle head and the auxiliary buckle head always have an elastic buckle connection state, which reduces the process of replacing the fuse after the fuse is blown and the resetting operation steps of the protective drop-type fuse. In the excessive separation state, the guide buckle head and the auxiliary buckle head are completely separated. This method is relatively a one-time operation and is not convenient for resetting. However, the isolation effect brought by the complete separation of the guide buckle head and the auxiliary buckle head can effectively extinguish the arc, and the dynamic and efficient arc extinguishing work lasts for 2-5 seconds, which reduces the situation where it is easy to reignite a few seconds after the initial arc extinguishing.

[0024] 4. The present invention can effectively pull and pull a plurality of concentrically arranged separation grid ring blocks up and down by setting a sliding shaft in coordination with a force-limiting block, and between two springs arranged up and down. Under high current conditions, the main driving hollow shaft and the armature are excessively stretched upward, causing the upper spring to be compressed and the lower spring to be stretched, and forming a traction force during separation, causing the separation grid ring block opening to be closed for a certain period of time, and elastically stretched up and down under the action of the spring, causing the separation grid ring block opening to be repeatedly closed for 2-5 seconds, and multiple arc extinguishing treatments are performed on the arc and the re-ignition arc.

[0025] 5. The present invention is based on a small current condition in which the movable contact operates, causing the fuse to melt and generate an arc. At the same time, relative to the conventional current, the current in the small current condition increases, causing the magnetic induction coil to lift the main drive hollow shaft through the armature drive, and the multi-stage restoring spring to move in a relatively small compression path. The armature lifts and drives the main drive hollow shaft and multiple separation grid ring blocks to stretch, so as to radially separate the arc. In this way, the protective fuse tube assembly is less damaged and the accessories are easy to reset and replace.

[0026] 6. In the high-current condition of the present invention, the moving contact causes the fuse to blow and generate an arc. At the same time, compared with the conventional current, the increase in current in the high-current condition causes the magnetic induction coil to drive the main driving hollow shaft to lift through the armature, and the multi-stage restoring force spring moves through a relatively large compression path. The lifting of the armature drives the main driving hollow shaft and multiple partition grid ring blocks to be fully stretched, causing the guiding buckle to separate from the auxiliary buckle. Based on the action of gravity and the elastic restoring force of the spring, multiple partition grid ring blocks perform up-and-down restoring force pulling and pushing adjustments to continuously extinguish the arc generated in the high-current condition for a short time. Although this method increases the damage to the protective fuse tube assembly, it effectively improves the arc extinguishing effect and enhances the protection performance of the drop-type fuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic side view structure diagram of the whole of the present invention;

[0028] Figure 2 is a schematic perspective sectional structure diagram of the protective fuse tube assembly of the present invention;

[0029] Figure 3 is a schematic perspective disassembled structure diagram of the protective fuse tube assembly of the present invention;

[0030] Figure 4 is a schematic side view structure diagram of the inside of the protective fuse tube assembly of the present invention;

[0031] Figure 5 is a schematic perspective sectional structure diagram of the multi-stage pulling and pushing assembly of the present invention;

[0032] Figure 6 In the present invention Figure 5 is a partial enlarged structure diagram at A in

[0033] Explanation of the reference numerals in the drawings:

[0034] 1. Mounting bracket; 2. Insulating support; 3. Buckling arm; 4. Rotating shaft connecting arm; 5. Protective fuse tube assembly; 6. Fuse tube body; 7. Moving contact; 8. Magnetic induction coil; 9. Armature; 10. Auxiliary supporting seat; 11. Multi-stage restoring force spring; 12. Multi-stage arc extinguishing structure;

[0035] 601. Restoring force cavity; 602. Arc extinguishing cavity; 603. Connecting sliding seat;

[0036] 801. Fuse buckle;

[0037] 901. Guiding buckle;

[0038] 1201. Main driving hollow shaft; 12011. Auxiliary buckle; 12012. Partition groove; 1202. Multi-stage telescopic assembly; 12021. Partition grid ring block; 12022. Accommodating groove; 12023. Sliding shaft; 12034. Spring; 12035. Force limiting block. Detailed implementation mode

[0039] As Figures 1 to 6 As shown in the figure, a protective drop-out fuse according to the present invention includes an installation bracket 1; an insulating support 2 is inclinedly arranged at the end of the installation bracket 1 through bolts; a buckling support arm 3 is arranged at the top of the insulating support 2; a rotating shaft connecting support arm 4 is arranged at the bottom of the insulating support 2; a protective fuse tube assembly 5 is arranged on the rotating shaft connecting support arm 4 through a rotating fastener; the protective fuse tube assembly 5 includes a fuse tube main body 6; the fuse tube main body 6 is rotatably arranged at the rotating end of the rotating shaft connecting support arm 4 through a rotating fastener; wherein, a restoring force cavity 601 and an arc extinguishing cavity 602 are sequentially arranged in the fuse tube main body 6 from top to bottom; a movable contact 7 is buckled and arranged at the top of the fuse tube main body 6; wherein, at least one magnetic induction coil 8 is fixedly arranged at the bottom of the movable contact 7 relative to the inside of the fuse tube main body 6; wherein, the connecting end of the movable contact 7 and the magnetic induction coil 8 is fixedly connected; an armature 9 is arranged inside the fuse tube main body 6; an auxiliary supporting seat 10 is fixedly arranged at the top of the armature 9; a multi-stage restoring force spring 11 is arranged at the top of the auxiliary supporting seat 10; a multi-stage arc extinguishing structure 12 is arranged at the bottom of the armature 9; wherein, the multi-stage arc extinguishing structure 12 is a telescopic mechanism. Based on the magnitude of the current passing through, the present invention generates different current conditions, and through different current conditions, the magnetic induction coil 8 is used to drive the armature 9 to perform different upward length adjustment operations, so as to cause the multi-stage arc extinguishing structure 12 to perform arc extinguishing work in different states, and the arc extinguishing work of the protective fuse tube assembly 5 is effectively maintained by mechanical means, effectively reducing the insufficient stability of chemical arc extinguishing.

[0040] In the embodiment of the present invention, a connecting sliding seat 603 for basic support and guidance of the armature 9 is arranged between the fuse tube main body 6 and the restoring force cavity 601 and the arc extinguishing cavity 602; a fuse buckle 801 for connecting with a fuse is arranged at the output end of the magnetic induction coil 8, and the fuse is installed and connected to the fuse buckle 801 through a fastener. Wherein, at least one resistance increasing part is arranged on the middle surface of the fuse at least in the arc extinguishing area of the multi-stage arc extinguishing structure 12, and the resistance is increased to cause relatively large heat generation and melting at this position, so as to facilitate controlling the arc generation position, and the input end of the magnetic induction coil 8 is fixedly connected with the movable contact 7; a guiding buckle 901 is arranged at the bottom of the armature 9.

[0041] In an embodiment of the present invention, the auxiliary supporting seat 10 is in a "U" shape, and the top of the multi-stage restoring spring 11 is fixedly connected to the fuse tube main body 6, and the multi-stage restoring spring 11 is in a "hourglass" shape. In the present invention, the "U"-shaped auxiliary supporting seat 10 divides the axial position of the arc extinguishing chamber 602 into multiple cavities, and the basic arc extinguishing work is formed through the division; and in the present invention, by setting the multi-stage restoring spring 11 in a "hourglass" shape, it is possible to effectively distinguish between small or large current working conditions. Based on the "hourglass" shaped multi-stage restoring spring 11, the upward driving force of the armature 9 in the small current working condition can only perform basic compression work. In the large current working condition, the upward driving force of the armature 9 needs to synchronously Figure 4 As shown, the multi-stage restoring spring 11 is over-compressed negatively. This method effectively controls the upward adjustment of the armature 9 required in the large current working condition, reduces the unnecessary maintenance work caused by mis-triggering the specified value current.

[0042] In an embodiment of the present invention, the multi-stage arc extinguishing structure 12 includes a main driving hollow shaft 1201 arranged at the axis position of the fuse tube main body 6; an auxiliary buckle 12011 adapted to the guiding buckle 901 is provided at the top of the main driving hollow shaft 1201; and a dividing groove 12012 is opened at the top of the main driving hollow shaft 1201. In the present invention, the guiding buckle 901 and the auxiliary buckle 12011 are elastically buckled to form a basic connection state and an over-separation state. In the basic connection state, the guiding buckle 901 and the auxiliary buckle 12011 always have an elastically buckled connection state, which reduces the steps of replacing the fuse again after the fuse is melted and the reset operation of the protective drop-type fuse. In the over-separation state, the guiding buckle 901 and the auxiliary buckle 12011 are completely separated. This method is relatively a one-time operation and is not convenient for resetting. However, the separation effect brought by the complete separation of the guiding buckle 901 and the auxiliary buckle 12011 can effectively extinguish the arc, and a dynamic and efficient arc extinguishing work lasting between 2 and 5 seconds can reduce the situation that is easy to reignite in the first few seconds after the initial arc extinguishing.

[0043] In an embodiment of the present invention, a multi-stage pulling component 1202 is disposed outside the main drive hollow shaft 1201; the multi-stage pulling component 1202 includes a plurality of partition grid ring blocks 12021 arranged in concentric circles; receiving grooves 12022 are disposed on both sides of the partition grid ring block 12021; a sliding shaft 12023 is disposed in the receiving groove 12022; springs 12034 are disposed on both the upper and lower sides of the sliding shaft 12023; a force-receiving limiting block 12035 is disposed between the two springs 12034; wherein, the cross-section of the partition grid ring block 12021 is in the shape of a "[". Through the arrangement of the sliding shaft 12023 in cooperation with the force-receiving limiting block 12035, and between the two springs 12034 arranged up and down, the multi-stage pulling operation of the plurality of partition grid ring blocks 12021 arranged in concentric circles can be effectively carried out. In a large-current working condition, due to the excessive upward stretching of the main drive hollow shaft 1201 and the armature 9, the upper spring 12034 is compressed and the lower spring 12034 is stretched, and a traction force is formed during the separation, causing the opening of the partition grid ring block 12021 to close for a certain period of time, and elastic up and down stretching is formed under the action of the spring 12034, causing the opening of the partition grid ring block 12021 to repeat the closing operation within 2-5 seconds, and multiple arc extinguishing treatments are carried out on the arc and the reigniting arc.

[0044] In an embodiment of the present invention, the moving contact 7 causes the magnetic induction coil 8 to perform electromagnetic driving work to drive the armature 9 to move upward under a relatively small-current working condition, and the multi-stage composite spring 11 moves along a relatively small compression path, causing the armature 9 to upwardly drag the main drive hollow shaft 1201 through the guiding buckle 901, resulting in the stretching and separation of a plurality of partition grid ring blocks 12021, forming an axial stretching and separation structure for generating an arc under a relatively small-current working condition. Based on the moving contact 7 in a relatively small-current working condition, the fuse is melted and an arc is generated. At the same time, compared with the conventional current, the current increases in the relatively small-current working condition, causing the magnetic induction coil 8 to drive the main drive hollow shaft 1201 to rise through the armature 9, and the multi-stage composite spring 11 moves along a relatively small compression path. The armature 9 drives the main drive hollow shaft 1201 and a plurality of partition grid ring blocks 12021 to stretch to radially separate the arc. This method causes little damage to the protective fuse tube assembly 5 and is easy to reset and replace the accessories.

[0045] In an embodiment of the present invention, the moving contact 7 under a high-current condition causes the magnetic induction coil 8 to perform electromagnetic driving work to drive the armature 9 to move upward. The multi-stage restoring force spring 11 moves along a relatively large compression path, causing the armature 9 to drag the main driving hollow shaft 1201 upward through the guiding buckle 901. Moreover, the lifting distance of the main driving hollow shaft 1201 is greater than the maximum stretching distance of the multi-stage pulling component 1202, causing the guiding buckle 901 to separate from the auxiliary buckle 12011. With the arrangement of the spring 12034, the plurality of partition grid ring blocks 12021 are adjusted by restoring force pulling up and down, forming an axial multi-stage partition structure for extinguishing the arc generated under the high-current condition. Based on the moving contact 7 under the high-current condition in the present invention, the fuse melts and an arc is generated. At the same time, compared with the conventional current, the current increases in the high-current condition, causing the magnetic induction coil 8 to drive the main driving hollow shaft 1201 to lift through the armature 9, and the multi-stage restoring force spring 11 moves along a relatively large compression path. The main driving hollow shaft 1201 and the plurality of partition grid ring blocks 12021 are fully stretched by the lifting of the armature 9, causing the guiding buckle 901 to separate from the auxiliary buckle 12011. Based on the action of gravity and the elastic restoring force of the spring 12034, the plurality of partition grid ring blocks 12021 are adjusted by restoring force pulling up and down to continuously extinguish the arc generated under the high-current condition for a short time. Although this method increases the damage to the protective fuse tube assembly 5, it effectively improves the arc extinguishing effect and enhances the protection performance of the drop-out fuse.

[0046] Working principle: This embodiment provides a protective drop-out fuse, and the using steps are as follows:

[0047] S100. Install the fuse. Connect the fuse to the fuse buckle 801 through a fastener, and install the other end of the fuse to the connecting component of the rotating shaft connecting arm 4.

[0048] S200. Closing treatment: Use a tool to push the ring buckle on the side of the protective fuse tube assembly 5 to rotate, causing

[0049] the moving contact 7 to be buckled with the fixed contact.

[0050] S300. Arc extinguishing treatment:

[0051] If a small-current condition occurs; based on the moving contact 7 under the small-current condition, the fuse melts and an arc is generated. At the same time, compared with the conventional current, the current increases in the small-current condition, causing the magnetic induction coil 8 to drive the main driving hollow shaft 1201 to lift through the armature 9, and the multi-stage restoring force spring 11 moves along a relatively small compression path. The main driving hollow shaft 1201 and the plurality of partition grid ring blocks 12021 are stretched by the lifting of the armature 9 to radially partition the arc.

[0052] If a large current condition occurs; based on the moving contact 7 for the large current condition, the fuse is melted and an arc is generated. At the same time, compared with the conventional current, the increase in current in the large current condition causes the magnetic induction coil 8 to drive the main driving hollow shaft 1201 to lift through the armature 9, and the multi-stage composite force spring 11 moves through a relatively large compression path. The lifting of the armature 9 drives the main driving hollow shaft 1201 and a plurality of partition grid ring blocks 12021 to be fully stretched. As a result, the guiding buckle 901 is separated from the auxiliary buckle 12011. Based on the action of gravity and the elastic restoring force of the spring 12034, a plurality of partition grid ring blocks 12021 perform up and down restoring pull adjustment to continuously extinguish the arc generated in the large current condition for a short time.

[0053] The embodiments disclosed in the present invention are preferred embodiments, but are not limited thereto. Those of ordinary skill in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not depart from the spirit of the present invention, they are within the protection scope of the present invention.

Claims

1. A protective drop-out fuse, characterized in that, The invention comprises a mounting bracket (1); an insulating support (2) is arranged at an inclined shape at the end of the mounting bracket (1) by means of bolts; a buckle support arm (3) is arranged at the top of the insulating support (2); a rotating shaft connecting support arm (4) is arranged at the bottom of the insulating support (2); and a protective fuse assembly (5) is arranged on the rotating shaft connecting support arm (4) by means of a rotating fastener; The protective melting tube assembly (5) comprises a melting tube body (6); The fusion tube body (6) is rotatably arranged at the rotating end of the rotating shaft connecting support arm (4) through a rotating fastener; wherein the fusion tube body (6) is provided with a restoring chamber (601) and an arc extinguishing chamber (602) in sequence from top to bottom; A movable contact (7) is buckled and arranged on the top of the melting tube body (6); Wherein, at least one magnetic induction coil (8) is fixedly arranged at the bottom of the movable contact (7) relative to the inside of the melting tube body (6); wherein the movable contact (7) is fixedly connected to the connection end of the magnetic induction coil (8); An armature (9) is provided inside the melting tube body (6); An auxiliary support seat (10) is fixedly arranged on the top of the armature (9); a multi-stage restoring spring (11) is arranged on the top of the auxiliary support seat (10); A multi-stage arc extinguishing structure (12) is provided at the bottom of the armature (9); wherein the multi-stage arc extinguishing structure (12) is a telescopic mechanism; A guide buckle (901) is provided at the bottom of the armature (9); The multi-stage arc extinguishing structure (12) comprises a main driving hollow shaft (1201) arranged at the axial position of the melting tube body (6); an auxiliary buckle head (12011) adapted to the guide buckle head (901) is arranged at the top of the main driving hollow shaft (1201); A multi-stage pull-out assembly (1202) is arranged outside the main driving hollow shaft (1201); the multi-stage pull-out assembly (1202) comprises a plurality of partition fence ring blocks (12021) arranged in concentric circles; receiving grooves (12022) are arranged on both sides of the partition fence ring block (12021); a sliding shaft (12023) is arranged in the receiving groove (12022); springs (12034) are arranged on both upper and lower sides of the sliding shaft (12023); a force limiting block (12035) is arranged between the two springs (12034); Wherein, the cross section of the separation gate ring block (12021) is in the shape of "[".

2. The protective type drop-out fuse according to claim 1, wherein, A connecting sliding seat (603) for providing basic support and guidance for the armature (9) is provided between the melting tube body (6) and the restoring chamber (601) and the arc extinguishing chamber (602); The output end of the magnetic induction coil (8) is provided with a fuse buckle (801) for connecting to a fuse, and the input end of the magnetic induction coil (8) is fixedly linked to the movable contact (7).

3. The protective type drop-out fuse according to claim 2, characterized in that, The auxiliary support seat (10) is in the shape of a Chinese character "凵", and the top of the multi-stage restoring spring (11) is fixedly connected to the melting tube body (6), and the multi-stage restoring spring (11) is in the shape of an "hourglass".

4. The protective drop-out fuse according to claim 3, characterized in that, A dividing groove (12012) is provided on the top of the main driving hollow shaft (1201).

5. The protective drop-out fuse according to claim 4, characterized in that, The movable contact (7) under relatively low-current conditions causes the magnetic induction coil (8) to perform electromagnetic driving work to drive the armature (9) to move upward. The multi-stage composite force spring (11) moves along a relatively small compression path, causing the armature (9) to drag the main driving hollow shaft (1201) upward through the guiding buckle (901), resulting in the stretching and separation of several of the partition grid ring blocks (12021), forming an axial stretching and separating structure for the arc generated under low-current conditions.

6. The protective type drop-out fuse according to claim 5, characterized in that, The movable contact (7) under relatively high-current conditions causes the magnetic induction coil (8) to perform electromagnetic driving work to drive the armature (9) to move upward. The multi-stage composite force spring (11) moves along a relatively large compression path, causing the armature (9) to drag the main driving hollow shaft (1201) upward through the guiding buckle (901). Moreover, the lifting distance of the main driving hollow shaft (1201) is greater than the maximum stretching distance of the multi-stage pulling component (1202), causing the guiding buckle (901) to separate from the auxiliary buckle (12011). In combination with the setting of the spring (12034), several of the partition grid ring blocks (12021) are adjusted by upward and downward composite force pulling to form an axial multi-stage partitioning structure for the arc generated under high-current conditions.

7. A method for using a protective drop fuse, which is applicable to a protective drop fuse described in claim 6, characterized in that, It includes the following steps: S100. Fuse installation: The fuse is installed and connected to the fuse buckle (801) through a fastener, and the other end of the fuse is installed and connected to the connecting component of the rotating shaft connecting arm (4). S200. Closing treatment: A tool is used to push the ring buckle on the side of the protective fuse tube assembly (5) to rotate, causing the movable contact (7) to be buckled with the fixed contact. S300. Arc extinguishing treatment: If a low-current condition occurs; due to the low-current condition of the movable contact (7), the fuse melts and an arc is generated. At the same time, compared with the normal current, the current increases in the low-current condition, causing the magnetic induction coil (8) to drive the main driving hollow shaft (1201) to lift through the armature (9), and the multi-stage composite force spring (11) moves along a relatively small compression path. The lifting of the armature (9) drives the main driving hollow shaft (1201) and multiple partition grid ring blocks (12021) to stretch, so as to radially partition the arc. If a high-current condition occurs; due to the high-current condition of the movable contact (7), the fuse melts and an arc is generated. At the same time, compared with the normal current, the current increases in the high-current condition, causing the magnetic induction coil (8) to drive the main driving hollow shaft (1201) to lift through the armature (9), and the multi-stage composite force spring (11) moves along a relatively large compression path. The lifting of the armature (9) drives the main driving hollow shaft (1201) and multiple partition grid ring blocks (12021) to stretch sufficiently, causing the guiding buckle (901) to separate from the auxiliary buckle (12011). Based on the action of gravity and the elastic restoring force of the spring (12034), multiple partition grid ring blocks (12021) are adjusted by upward and downward composite force pulling to perform short-time continuous arc extinguishing work on the arc generated under high-current conditions.

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