A dual-break excitation fuse

Abstract

A dual-break excitation fuse includes a housing, an excitation source, a power unit, and a conductor passing through the housing. Two pre-breaks are spaced apart on the conductor within the housing, with the impact surfaces of the two pre-breaks at different heights. A fusible element is connected in parallel to both ends of the pre-break that breaks first on the conductor. The power unit sequentially breaks the two pre-breaks on the conductor, forming two breaks on the conductor. This invention has a simple structure, is easy to assemble, small in size, light in weight, has high breaking capacity, and can adapt to breaking within the entire current range.

Description

Technical Field

[0001] This invention relates to circuit protection in the field of power or electric vehicles, and in particular to circuit protection devices that can promptly disconnect the circuit to protect it when needed or when a fault current occurs. Background Technology

[0002] Currently, in addition to traditional thermal fuses, a type of switch that quickly cuts off the circuit has emerged in power control and electric vehicle protection devices, and this type of switch is gradually being widely used in the electric vehicle field. Its widespread application stems from its ability to overcome the limitations of traditional fuses, which are forced to operate and cannot provide full-range protection. This type of switch can actively cut off the protected circuit within a specified time through control signals. However, with the increasing demands for electric vehicle range and the expanding capacity of battery packs, the requirements for protection devices in the circuit to cut off larger currents have exposed the limitations of this type of switch. To achieve high breaking capacity, two solutions are needed: increasing the cavity volume of the switch or adding vents to the cavity to reduce the gas pressure and prevent bursting. The first solution contradicts the current trend towards smaller size and integration. The second method involves venting arc gas, which affects the safety and insulation of the entire battery pack. Therefore, a solution is urgently needed for an excitation fuse structure that can improve breaking capacity, eliminate venting, and provide full-range protection. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an excitation fuse with double breaks, which achieves the sequential disconnection of the double breaks on the conductor by means of the different heights of the two pre-break points on the conductor, and the series and parallel connection with the fusible element, thereby improving the breaking capacity and arc extinguishing capacity.

[0004] To solve the above-mentioned technical problems, the present invention provides a double-break excitation fuse, including a housing, an excitation source, a power device, and a conductor. The conductor is installed in the housing, with its two connecting ends located outside the housing. The excitation source and the power device are located in the housing on one side of the conductor. After receiving an excitation signal, the excitation source actuates, driving the power device to displace and disconnect the conductor. Two pre-breaks are spaced apart on the conductor located in the housing, and the impact surfaces of the two pre-breaks are at different heights. Fuses are connected in parallel at both ends of the pre-break that breaks first on the conductor. The power device disconnects the two pre-breaks on the conductor one after the other, forming two breaks on the conductor.

[0005] Preferably, at least one end of the pre-break of the conductor is provided with a weak break, and the conductor portion between the two pre-breaks is supported by the housing support portion.

[0006] Preferably, a rotational weak point is provided at the other end of the pre-break of the conductor.

[0007] Preferably, at least one arc-extinguishing chamber is provided in the housing, the melt passes through the arc-extinguishing chamber, and the two ends of the melt pass through the arc-extinguishing chamber and are connected in parallel to the two ends of the pre-break point of the conductor that is first broken.

[0008] Preferably, the impact end of the power device includes two impact heads spaced apart, each impact head corresponding to one of the pre-breaks; the two impact heads have different heights, with the impact head corresponding to the side of the conductor pre-break that is impacted having a higher height.

[0009] Preferably, the end of the power device adjacent to the excitation source is a cylindrical structure, and the two impact heads are integrally connected to the cylindrical structure; one of the impact heads has an impact end face that is a notch structure that can span the width of the conductor pre-break; reinforcing ribs are respectively provided on the outer side of the two impact heads; and limiting structures that limit the initial position of the power device are respectively provided on the side of the two impact heads near the conductor.

[0010] Preferably, a sealing groove is provided on the outer circumferential surface of the cylindrical structure, and a sealing device for sealing the gap between the power device and the cavity of the housing is provided in the sealing groove.

[0011] Preferably, the end face of the power device adjacent to the excitation source is an arc-shaped concave structure, and several grooves for adjusting the air pressure are spaced apart on the arc-shaped concave structure.

[0012] Preferably, several energy-absorbing ribs are provided on the end face of the cylindrical structure between the two impact heads. After the power device disconnects the conductor, the energy-absorbing ribs can collide with the conductor portion between two adjacent pre-break points to release kinetic energy.

[0013] Preferably, the housing includes a first housing for accommodating the excitation source and the power device, a second housing for the conductor disconnection portion to fall into, and a third housing for accommodating the molten material; the conductor passes through the first housing and the second housing; the excitation source and the power device are respectively disposed in the first housing, the molten material passes through the arc-extinguishing chamber in the third housing, and a protective cover is located outside the first housing to fix the excitation source.

[0014] Preferably, a nested concave-convex structure is provided between the contact surfaces of the first housing and the second housing to accommodate and limit the conductor; the cavities of the first housing and the second housing are connected and docked to form a channel for the displacement of the power device; and a clearance notch is provided at one end of the contact surface between the cavity of the first housing and the second housing, at the position of the limiting structure on the corresponding power device that defines the initial position, to accommodate the limiting structure.

[0015] Preferably, the first housing has a convex structure and is provided with several reinforcing ribs.

[0016] Preferably, two supporting beams are arranged parallel to each other in the cavity into which the conductor disconnected portion falls. An I-shaped placement groove is formed between the two supporting beams and between the two ends of the two supporting beams and the cavity wall of the second housing. An I-shaped support is placed in the I-shaped placement groove. The two supporting beams and the I-shaped support are located between the two pre-broken ends of the conductor to support the conductor.

[0017] Preferably, two supporting beams are arranged parallel to each other in the cavity into which the conductor disconnected portion falls, one of which is connected only to the bottom of the cavity of the second housing; a C-shaped placement groove is formed between the two supporting beams and between the two ends of the two supporting beams and the cavity wall of the second housing, and a C-shaped support is placed in the C-shaped placement groove; the two supporting beams and the C-shaped support are located between the two pre-break points of the conductor to support the conductor.

[0018] Preferably, two supporting beams are arranged parallel to each other in the cavity into which the conductor disconnected portion falls, and both supporting beams are connected to the bottom of the cavity of the second housing; a straight groove is formed between the two supporting beams and between the two ends of the two supporting beams and the cavity wall of the second housing, and a straight support is placed in the straight groove; the two supporting beams and the straight support are located between the two pre-broken ends of the conductor to support the conductor.

[0019] Preferably, a mechanical seal structure with sealing contact surfaces is provided on the contact surfaces of the first housing and the second housing, respectively.

[0020] The excitation fuse of this invention employs pre-break sections of different conductor heights and a power device with a different impact head height to achieve sequential disconnection of the two pre-break sections. Parallel fusible elements improve breaking capacity and arc-extinguishing capability; simultaneously, the different structures of the first and second housings achieve a more compact structure, lighter weight, and smaller size, while ensuring the structural strength of the excitation fuse housing. The housing structure of this invention simplifies the assembly of the excitation fuse. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the excitation fuse of the present invention.

[0022] Figure 2 Figure 1 is a schematic diagram of the first shell structure; wherein, Figure 2a is a schematic diagram of the structure from the side of the contact surface that contacts the second shell, and Figure 3b is a schematic diagram of the structure from the outside of the first shell.

[0023] Figure 3 This is a schematic diagram of a conductor structure.

[0024] Figure 4These are schematic diagrams of the power unit structure; where, a is a three-dimensional schematic diagram of the power unit, b is a bottom view of the power unit structure, c is a top view of the power unit structure, d is a schematic diagram of one side of the impact head with a notch structure of the power unit, and e is a schematic diagram of the impact head structure on the other side of the power unit.

[0025] Figure 5 This is a schematic diagram of the impact head of the power unit having an inclined plane structure.

[0026] Figure 6 These are schematic diagrams of the second shell structure, where diagram a is a three-dimensional structural diagram of the second shell viewed from top to bottom, and diagram b is a three-dimensional structural diagram of the second shell viewed from bottom to top.

[0027] Figure 7 Figure 1 is a schematic diagram of another structure of the second shell, where Figure 2a is a schematic diagram of the front structure of the second shell, Figure 3b is a schematic diagram of the structure with the support member inserted, and Figure 4c is a schematic diagram of the structure of the I-shaped support member.

[0028] Figure 8 Figure 1 is a schematic diagram of another structure of the second shell, where Figure 2a is a schematic diagram of the front structure of the second shell, Figure 3b is a schematic diagram of the structure with the support member inserted, and Figure 4c is a schematic diagram of the structure of the C-shaped support member.

[0029] Figure 9 It is a melt structure, where Figure a shows one structural form of melt connecting to a conductor, and Figure b shows another structural form of melt connecting to a conductor. Detailed Implementation

[0030] Regarding the above technical solution, preferred embodiments will be described first, along with detailed explanations in conjunction with the accompanying drawings.

[0031] In this invention, the descriptions of positional relationships, such as up, down, left, right, front, and back, are only for better understanding of this invention and are not intended to limit the positional relationships.

[0032] See Figure 1 The excitation fuse includes a first housing 1, a second housing 2, a conductor 3 located between the first and second housings, an excitation source 5 and a power unit 4 arranged sequentially from top to bottom in the first housing 1, and a third housing 6 located below the second housing, containing a fusible element 7. The fusible element 7 is connected in parallel to the two outer sides of the pre-break point of the conductor. A protective cover 8 is located outside the first housing to fix the excitation source. The first, second, and third housings are all made of insulating material and are integrally molded by injection molding. Wherein:

[0033] First shell 1, see Figure 2The material is insulating and injection molded. Its shape is convex, which reduces the material usage and weight of the first housing. A cavity 101 extending through both ends of the first housing 1 is formed, and a cavity 201 communicating with the cavity of the first housing is formed on the second housing 2. The cavity in the smaller diameter portion of the first housing 1 has a stepped structure, on which an excitation source 5 is installed. A sealing device 110, which is a sealing ring, is provided between the excitation source 5 and the stepped surface of the cavity 101. A foolproof notch 102 is formed on the inner wall of the upper opening of the cavity 101. A foolproof protrusion is provided on the excitation source that can be placed in the notch 102. After the excitation source is installed in the cavity, the foolproof protrusion on the excitation source is accommodated in the foolproof notch 102 to prevent incorrect installation. The excitation source is a gas generator that can accept excitation electrical signals and releases high-pressure gas after ignition, driving the displacement of the power unit 4.

[0034] Anti-slip ridges 103 and process error prevention notches 104 are provided on the outer periphery of the small-diameter portion of the first housing. The inner wall of the protective cover 8 matches the structure of the first housing. When the protective cover is installed on the first housing and presses the excitation source 5, the anti-slip ridges 103 form an effective fit with the protective cover, preventing the protective cover from rotating and avoiding excessive bonding force between the protective cover and the first housing. The purpose of the process error prevention notches 104 is to ensure that the first housing matches the feeding fixture during automatic feeding in the fuse assembly process.

[0035] Several reinforcing ribs 105 are arranged at intervals on the outer periphery of the first shell to reduce the weight of the first shell while ensuring the structural strength of the first shell.

[0036] Conductor 3, see Figure 3 The conductor 3 is a long, strip-shaped structure made of a non-elastic conductive metal. It passes between the first and second housings, with its two ends on the outside serving as connection points for external circuitry. These connection points are integral with the conductor portion inside the housing, or they can be a conductive connection structure. Two weak points (301, 302) are spaced apart on conductor 3. The conductor portion between these two weak points (301, 302) forms a crossbeam 303. Rotational weak points (306, 307) are spaced at appropriate intervals on one side of each weak point. A pre-break 305 is formed between weak point 301 and rotational weak point 307, and a pre-break 304 is formed between weak point 302 and rotational weak point 306. The widths of pre-breaks 304 and 305 are narrower than the width of the conductor body. The thickness of pre-break 305 is greater than the thickness of pre-break 304, and the surface of pre-break 305 on the power unit side is higher than the surface of pre-break 304. When the two impact heads of the power unit are at the same height, the pre-break 305 is the first to be broken by the impact of the power unit.

[0037] A variable cross-section structure is set between the weak point (306, 307) and the conductor connection end. A positioning structure 308 and a foolproof structure 309 are respectively set on both sides of the variable cross-section structure. Both the positioning structure and the foolproof structure are protrusion structures. The difference between the foolproof structure and the positioning structure is that the protrusion structures on both sides of the variable cross-section structure are different in shape.

[0038] Both disconnecting and rotating weak points reduce the mechanical strength of the conductor, but the mechanical strength of a rotating weak point is greater than that of a disconnected weak point. Disconnected and rotating weak points can be groove structures that extend through the width of the conductor, such as U-shaped grooves, V-shaped grooves, or wavy groove structures. Disconnected weak points can also be through-hole structures arranged in rows at intervals, conductive overlap structures, etc.

[0039] The power unit 4 is made of insulating material and is integrally molded using injection molding. (See attached image.) Figure 4 The end adjacent to the excitation source is a cylindrical structure 401, and the end adjacent to the conductor is an impact end, which includes two impact heads (402, 403). A circumferential groove 404 is formed on the outer cylindrical surface of the cylindrical structure 401, and a sealing ring 405 is placed in the circumferential groove 404 to achieve sealing between the power device and the contact surface of the first housing cavity 101.

[0040] Impact heads 402 and 403 are spaced apart. The impact end face of impact head 402 is a notch structure 402a, the width of which is greater than the width of the corresponding conductor pre-cut opening. This ensures that when the power device disconnects the conductor, the notch structure 402a of impact head 402 accommodates the corresponding pre-cut opening within it, thus disconnecting the conductor. The impact end face of impact head 403 is higher than the notch structure of impact head 402. The notch structure 402a and the impact end face of impact head 403 can be planar, inclined, V-shaped, or other structures conducive to disconnecting the conductor. (See reference...) Figure 5 The diagram shows the impact head of the power unit, which has an inclined plane structure.

[0041] Reinforcing ribs 406 are provided on the outer surfaces of the two impact heads; limiting structures 407 for defining the initial position of the power device are provided on the side ends of the two impact heads near the conductor. Several sealing ridges 408 that can seal against the housing are provided at intervals on the outer circumference of the power device. Several energy-absorbing ribs 409 are provided at intervals on the bottom of the cylindrical structure between the two impact heads. When the power device moves to the lower stop position, it collides with the crossbeam in the middle of the conductor, causing damage and absorbing energy. The end face of the cylindrical structure 401 adjacent to the excitation source is a groove-shaped arc surface structure. A cavity 410 that does not penetrate the thickness of the cylindrical structure 401 is provided on the arc surface structure. By adjusting the size of the cavity 410, the gas pressure can be adjusted, thereby adjusting the different movement speeds of the power device.

[0042] See Figure 1 , Figure 2 , Figure 6 The first and second housings have concave and convex structures on their contact surfaces to accommodate and limit the conductor 3. In this embodiment, the first housing is configured as a protruding structure 106 protruding from the contact surface, and the second housing is configured as a receiving groove 202 recessed into the contact surface. The shapes of the protruding structure 106 and the receiving groove 202 match the shape of the conductor located between the contact surfaces of the first and second housings. Corresponding positioning structures (106a, 202a) and foolproof structures (106b, 202b) are provided on them to correspond to the conductor structure. The positioning structure and the foolproof structure are grooves and protrusions that engage with them.

[0043] At the port of cavity 101 on the conductor side of the first housing, a clearance notch is provided to accommodate the limiting structure 407 of the power device. The inner diameter of the cavity portion where the power device is installed is larger than the inner diameter of the cavity portion where the excitation source is installed. When the power device is installed into the cavity 101 of the first housing, the limiting structure 407 is engaged in the clearance notch. After the first and second housings are joined, the clearance notch and the limiting structures on the end faces of the second housings further secure the limiting structure 407 within the clearance notch, thus fixing the initial position of the power device. The use of the clearance notch and the limiting structure on the impact end side of the power device facilitates the installation of the power device into the cavity 101 from the conductor side of the first housing.

[0044] A mechanical seal structure with sealing contact surfaces is provided on the contact surfaces of the first housing and the second housing. In this embodiment, the sealing structure consists of a sealing ridge 107 and a sealing groove 108 on the contact surface of the first housing. The sealing ridge 107 is located on both sides of the protruding structure 106 and connected to the protruding structure. The sealing groove 108 is located within the sealing ring formed by the sealing ridge and the protruding structure 106, and two sets of sealing grooves 108 are provided on opposite sides of the cavity. Sealing grooves 206 and sealing ridges 207 are provided on the contact surfaces of the second housing and the first housing at positions corresponding to the sealing ridge 107 and sealing groove 108, respectively. The sealing between the contact surfaces and the cavity is achieved through the nested sealing of the sealing ridge and sealing groove between the contact surfaces of the first housing and the second housing.

[0045] A vertical groove 109 is provided in the cavity 101 of the first housing, and a protrusion 204 is provided in the cavity 201 of the second housing corresponding to the vertical groove 109. The groove 109 and the protrusion 204 are joined together to form a complete slide for the power device. The sealing protrusion 408 of the power device is located in the groove 109, ensuring that the power device slides along the slide and preventing the power device from rotating. At the same time, when the power device enters the inner surface of the protrusion 204 in the second housing, it achieves insulation sealing between the two breaks of the conductor, and interrupts the arc transmission between the breaks.

[0046] Two parallel supporting beams 203, integrally connected to the cavity wall, are spaced apart within the second housing cavity 201 to support the conductor beams. The rigid contact between the supporting beams and the conductor provides a larger contact area for the conductor beams. Simultaneously, the supporting beams 203 divide the cavity 201 into two independent cavities (201a and 201b), allowing the two impact heads of the power device to drive the broken portion of the conductor into them respectively. After the two impact heads of the power device enter cavities (201a and 201b), the energy-absorbing ribs of the power device collide with the conductor beams. The power device, the conductor beams, and the second housing supporting beams completely isolate cavities 201a and 201b, preventing arc crosstalk. The two outer sides of the supporting beams cooperate with the two inner sides of the two impact heads of the power device, extinguishing the arc through contact surface compression.

[0047] Multiple reinforcing ribs 205 are provided at the bottom of the cavity 201. The multiple reinforcing ribs 205 form several cavities that do not penetrate the bottom of the second shell. This is used to reduce the weight of the second shell and ensure its strength. At the same time, the electric arc is divided into small electric arcs in each cavity. The small electric arcs after being divided are extinguished in each cavity, thereby improving the arc extinguishing capability.

[0048] exist Figure 7 In the second housing, a gap is maintained between the two spaced-apart support beams 203a and the cavity wall of the cavity 201, forming a receiving groove 201c between the two support beams 203a. The receiving groove 201c is I-shaped. An independent support member 209, also I-shaped, is placed in the receiving groove 201c. The two support beams 203a are located on both sides of the support member 209, and the I-shaped support member 209 isolates the cavity 201 to form two cavities (201a, 201b). The support beams 203a are only integrally formed at the bottom and connected to the bottom of the cavity 201 of the second housing; the other sides are free surfaces. In cooperation with the I-shaped support member, when subjected to impact from the power device, the symmetrically arranged support beams can release the lateral deformation constraint of the support beams, forming a double-sided elastic constraint with the power device. The isolation of the two chambers of the second housing is achieved through the cooperation of the I-shaped support member and the conductor beam.

[0049] See Figure 8One of the supporting beams is structure 203a, which is integrally formed at its bottom and connected to the bottom of the cavity 201 of the second housing; its other sides are free surfaces. A receiving groove 201d is formed on one side of the supporting beam 203a, and this receiving groove 201d is C-shaped. A support member 210, matching the shape of the receiving groove 201d, is placed in the receiving groove 201d, covering the supporting beam 203a and its adjacent side. The support member 210 contacts the cavity wall and cooperates with the supporting beam to divide the cavity into two cavities (201a and 201b). Increasing the support member 210 provides a larger contact area for the conductor beam. Because the support member 210 is contained and limited in the receiving groove 201d, only one side of one of the supporting beams 203a is a free surface, forming a unilateral elastic constraint with the power unit, which can release a certain amount of lateral deformation.

[0050] A slot 206a is provided at the bottom of the second housing 2 for the two ends of the molten material 7 to pass through. After the molten material passes through the slot 206a at both ends after exiting the third housing, it is bent and electrically connected to the conductor. Supports 208 are respectively provided in the cavities 201(a) and 201(b) of the second housing. The supports 208 are used to support the variable cross-section structure part outside the weak point of the conductor rotation, so that after the conductor is pre-broken, it can be bent downward along the weak point of rotation and rotated into the cavity 201a or 201b.

[0051] Melt 7, see Figure 9 It is connected in parallel to the first pre-break of the conductor, forming a series relationship with the pre-break that breaks later.

[0052] See Figure 9 Figure a in the middle and Figure 6 After the two ends of the melt pass through slot 206a, they are connected to the outer sides of the first pre-break of the conductor, i.e., connected in parallel with the first pre-break and in series with the other pre-break. (See also...) Figure 9 Figure b in the middle and Figure 7 The bottom of the second housing 2 has slots 206a through which the two ends of the molten material 7 pass. After the two ends of the molten material 7 pass through the slots 206a, it is bent and then connected in parallel with the pre-break point where the conductor is first disconnected.

[0053] Melt 7 structure, see Figure 9 It has a spatial geometric structure. Its main body is a long strip-shaped structure, with four melt connection ends on both sides of each end. Figure 9 The parallel connection method of the melt in Figure a has good process feasibility because the melt directly passes through the pre-broken conductor and is connected in parallel. Figure 9 Figure b shows the molten metal connecting end passing through the arc-extinguishing chamber, then through the pre-break of the conductor after it breaks, and finally connecting in parallel with the pre-break of the conductor that breaks first. A magnetic field is formed at the conductor break, achieving magnetic blowout arc extinguishing.

[0054] The third housing 6 has an upward-opening arc-extinguishing chamber 601, which is sealed by an interference fit of a melt cover plate 602. The sealed arc-extinguishing chamber is filled with an arc-extinguishing medium. An arc-extinguishing medium filling hole is provided on the melt cover plate or the third housing for filling the arc-extinguishing medium; this hole is sealed after filling. The melt 7 passes through the arc-extinguishing chamber, through a recessed groove between the melt cover plate and the third housing, and then through a slot on the second housing before connecting in parallel with the conductor. The narrow diameter of the melt is located within the arc-extinguishing chamber. Both the third housing and the melt cover plate are made of insulating material and are injection molded.

[0055] Assembly process:

[0056] The melt 7 is placed on the third housing 6, and then the melt cover plate 602 is covered so that the two ends of the melt 7 pass through the receiving groove between the melt cover plate and the third housing and extend out of the third housing. The arc extinguishing medium is filled in the arc extinguishing chamber and the filling hole is sealed.

[0057] The second housing 2 is placed on the third housing 6, with both ends of the molten material 7 passing through the slots 206a on the second housing. The conductor is placed on the receiving groove 202, and then the molten material is bent and electrically connected to the conductor. The connection between the molten material and the conductor is achieved by welding. Alternatively, bolting or other connection methods can be used.

[0058] A sealing ring is fitted into the sealing groove of the power unit, and then the power unit is inserted into the cavity 101 from the bottom of the first housing with an interference fit, so that the limiting protrusion of the power unit is located in the clearance notch. The first housing is placed on top of the second housing and the conductor, so that the concave and convex structure between the contact surfaces of the first housing and the second housing fits and presses the conductor. Then the excitation source 5 is placed into the cavity 101 of the first housing, and a protective cover is fitted. Finally, the protective cover, the first housing, the second housing, and the third housing are fixedly connected by bolts.

[0059] The assembly process described above can be adjusted in sequence as needed.

[0060] Working principle of the invention:

[0061] When there is a small fault current or zero current, the conductor is driven by the power device to first disconnect the pre-break of the conductor with the higher height to form a break, and a small electric arc is formed at the break. Then, the other pre-break is connected in series with the molten metal, and most of the current passes through the unbroken pre-break and the parallel molten metal. Then the power device disconnects the other pre-break of the conductor to form a break and break the circuit, and a small electric arc is formed at the break. The small electric arc can be extinguished by air.

[0062] During a large fault current, the conductor, driven by the power device, first disconnects the pre-break with the higher conductor height to form a break, creating a small arc at the break. Then, the other pre-break is connected in series with the molten metal, and most of the current flows through the unconnected pre-break and the parallel molten metal. Then, the power device disconnects the other pre-break of the conductor to form a break, and the molten metal melts to form a break, breaking the circuit. The voltage division effect of the two series breaks reduces the size of the arc at each break, and the small arc can be extinguished by air. At the same time, the arc generated by the molten metal breaking is extinguished in the arc-extinguishing medium.

Claims

1. A double-break excitation fuse, comprising a housing, an excitation source, a power unit, and a conductor, wherein the conductor is disposed within the housing, with its two connecting ends located outside the housing, and the excitation source and the power unit located within the housing on one side of the conductor; the excitation source actuates upon receiving an excitation signal, driving the power unit to displace and disconnect the conductor; characterized in that, Two pre-breaks are spaced apart on the conductor located in the housing, and the two pre-breaks are impacted at different heights; molten material is connected in parallel at both ends of the first pre-break on the conductor; the power device disconnects the two pre-breaks on the conductor one after the other, forming two breaks on the conductor.

2. The double-break excitation fuse according to claim 1, characterized in that, The conductor has a weak break at at least one end of the pre-break, and the conductor portion between the two pre-breaks is supported by the housing support.

3. The double-break excitation fuse according to claim 2, characterized in that, A rotational weak point is provided at the other end of the pre-break of the conductor.

4. The double-break excitation fuse according to claim 1, characterized in that, At least one arc-extinguishing chamber is provided in the housing, the molten material passes through the arc-extinguishing chamber, and the two ends of the molten material pass through the arc-extinguishing chamber and are connected in parallel to the two ends of the pre-break point of the conductor that is first broken.

5. The double-break excitation fuse according to claim 4, characterized in that, The melt has a spatial geometric structure, and its two ends pass through the arc-extinguishing chamber, then pass through the pre-break of the conductor after being disconnected, and are connected in parallel to the pre-break of the conductor at the point where it was first disconnected.

6. The double-break excitation fuse according to claim 1, characterized in that, The impact end of the power device includes two impact heads spaced apart, each corresponding to one of the pre-break points; the two impact heads have different heights, with the impact head corresponding to the side of the conductor pre-break point that is impacted having a higher height.

7. The double-break excitation fuse according to claim 6, characterized in that, The power device and the excitation source are adjacent to a cylindrical structure at one end, and the two impact heads are integrally connected to the cylindrical structure; the impact end face of one of the impact heads is a notch structure that can span the width of the conductor pre-break; reinforcing ribs are respectively provided on the outer side of the two impact heads; limiting structures that limit the initial position of the power device are respectively provided on the side of the two impact heads near the conductor.

8. The double-break excitation fuse according to claim 7, characterized in that, A sealing groove is provided on the outer circumferential surface of the cylindrical structure, and a sealing device is provided in the sealing groove to seal the gap between the power device and the cavity of the housing.

9. The double-break excitation fuse according to claim 7, characterized in that, The end face of the power device adjacent to the excitation source is an arc-shaped concave structure, and several grooves for adjusting the air pressure are spaced apart on the arc-shaped concave structure.

10. The double-break excitation fuse according to claim 7, characterized in that, Several energy-absorbing ribs are provided on the end face of the cylindrical structure between the two impact heads. After the power device disconnects the conductor, the energy-absorbing ribs can collide with the conductor portion between two adjacent pre-break points to release kinetic energy.

11. The double-break excitation fuse according to any one of claims 1 to 10, characterized in that, The housing includes a first housing for housing the excitation source and the power device, a second housing for the conductor disconnection portion to fall into, and a third housing for housing the molten material; the conductor passes through the first housing and the second housing; the excitation source and the power device are respectively disposed in the first housing, the molten material passes through the arc-extinguishing chamber in the third housing, and a protective cover is located outside the first housing to fix the excitation source.

12. The double-break excitation fuse according to claim 11, characterized in that, A nested concave-convex structure is provided between the contact surfaces of the first housing and the second housing to accommodate and limit the conductor; the cavities of the first housing and the second housing are connected and docked to form a channel for the displacement of the power device; a clearance notch is provided at one end of the contact surface between the cavity of the first housing and the second housing, at the position of the limiting structure on the power device that defines the initial position, to accommodate the limiting structure.

13. The double-break excitation fuse according to claim 11, characterized in that, The first housing has a convex structure and is provided with several reinforcing ribs.

14. The double-break excitation fuse according to claim 11, characterized in that, The second housing has two parallel support beams that are integrally connected to the cavity wall of the second housing cavity, which are arranged in parallel in the cavity into which the conductor breaks. The support beams are located between the two pre-break points of the conductor to support the conductor.

15. The double-break excitation fuse according to claim 11, characterized in that, Two supporting beams are arranged parallel to each other in the cavity into which the conductor disconnected portion falls. An I-shaped placement groove is formed between the two supporting beams and between the two ends of the two supporting beams and the cavity wall of the second housing. An I-shaped support is placed in the I-shaped placement groove. The two supporting beams and the I-shaped support are located between the two pre-break points of the conductor to support the conductor.

16. The double-break excitation fuse according to claim 11, characterized in that, Two supporting beams are arranged parallel to each other in the cavity into which the conductor disconnects. One of the supporting beams is connected only to the bottom of the cavity of the second housing. A C-shaped placement groove is formed between the two supporting beams and between the two ends of the two supporting beams and the cavity wall of the second housing. A C-shaped support is placed in the C-shaped placement groove. The two supporting beams and the C-shaped support are located between the two pre-break points of the conductor to support the conductor.

17. The double-break excitation fuse according to claim 11, characterized in that, Two supporting beams are arranged parallel to each other in the cavity into which the conductor disconnects, and both supporting beams are connected to the bottom of the cavity of the second housing. A straight groove is formed between the two supporting beams and between the two ends of the two supporting beams and the cavity wall of the second housing. A straight support is placed in the straight groove. The two supporting beams and the straight support are located between the two pre-break points of the conductor to support the conductor.

18. The double-break excitation fuse according to claim 11, characterized in that, Mechanical seal structures with sealing contact surfaces are respectively provided on the contact surfaces of the first housing and the second housing.

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