Silver fuse

Abstract

The utility model discloses a silver fuse which comprises a silver fuse monofilament and constantan wires, the number of the constantan wires is two, the constantan wires are respectively processed into a left-handed spring shape and a right-handed spring shape, the two constantan wires are respectively wound on the surface of the silver fuse monofilament and are arranged in a staggered manner, and the silver fuse further comprises pins. The two ends of the silver fuse monofilament are fixedly connected with pins, the two ends of the two constantan wires are electrically connected with the pins, the silver fuse further comprises insulation supporting rings, the insulation supporting rings are fixed to the two ends of the silver fuse monofilament, the two ends of the two constantan wires are fixedly arranged on the insulation supporting rings, and the two ends of the constantan wires are electrically connected with the pins. The insulation supporting ring is made of ceramic or glass fiber, gaps of the constantan wire are filled with nanoscale aluminum oxide particles, and the surface of the constantan wire is coated with reversible thermosensitive paint. The constantan wire adopts a left-handed and right-handed double-helix structure, the equivalent inductance is less than 0.1 mu H (the equivalent inductance is about 1 mu H in the traditional single-helix inductor), and high-frequency surge oscillation of more than 10MHz can be inhibited.

Description

Technical Field

[0001] This utility model relates to the technical field of alloy wires, specifically a silver fused wire. Background Technology

[0002] Converters in photovoltaic and wind power systems have long faced the following surge threats:

[0003] Lightning surge: Lightning strikes in nature can generate transient overvoltages of tens of kilovolts, which can be coupled to the converter through the power grid or the connection lines of photovoltaic / wind power equipment, causing semiconductor devices (such as IGBTs and MOSFETs) to break down.

[0004] Operational surges: Operations such as grid switching and capacitor switching can trigger high-frequency oscillating overvoltages (frequency can reach MHz level), which may cause malfunctions in the converter control circuit or thermal damage to components.

[0005] Short-circuit surge: When an internal component of the converter short-circuits (such as an electrolytic capacitor bursting or a busbar breakdown), the instantaneous current can reach 10-20 times the rated current (e.g., the short-circuit current of a 100kW converter can reach 2000A), requiring rapid disconnection within microseconds.

[0006] Traditional protection solutions (such as ordinary fuses and metal oxide varistors, MOV) have the following limitations:

[0007] Ordinary fuses: slow breaking speed (>10ms), unable to suppress high-frequency surges; prone to arcing when melting, which may cause secondary faults.

[0008] MOV: It has aging problems when subjected to long-term power frequency voltage, resulting in a short lifespan (approximately 10,000 impacts); the residual voltage is high under high current, and the protection accuracy is insufficient. Utility Model Content

[0009] In view of the shortcomings of the prior art, this utility model provides a silver fuse, which solves the problems mentioned above.

[0010] To achieve the above objectives, this utility model is implemented through the following technical solution: a silver fused wire, comprising a silver fused monofilament and a constantan wire, wherein two constantan wires are provided, which are respectively processed into a left-handed spring shape and a right-handed spring shape, and the two constantan wires are respectively wound on the surface of the silver fused monofilament and arranged in a staggered manner.

[0011] Preferably, the silver fuse further includes leads, and both ends of the silver fuse are fixedly connected to leads, and the two constantan wires are electrically connected to the leads at both ends.

[0012] Preferably, the silver fused wire further includes an insulating support ring, which is fixed at both ends of the silver fused monofilament, and the two ends of the two constantan wires are fixedly mounted on the insulating support ring.

[0013] Preferably, the insulating support ring is made of either ceramic or glass fiber.

[0014] Preferably, the gaps between the constantan wires are filled with nano-sized alumina particles.

[0015] Preferably, the constantan wire is coated with a reversible thermosensitive coating.

[0016] Preferably, the constantan wire is coated with a silicone rubber insulating varnish layer.

[0017] Preferably, the insulating support ring has a through groove, through which a constantan wire passes and is fixed to the pin.

[0018] Beneficial effects

[0019] This invention provides a silver fuse. Compared with the prior art, it has the following advantages:

[0020] Double-helix reverse winding to eliminate inductance: The constantan wire adopts a left-hand + right-hand double-helix structure, with an equivalent inductance of <0.1μH (compared to about 1μH for a traditional single-helix inductor). This can suppress high-frequency surge oscillations above 10MHz and avoid overvoltage reflection caused by inductive coupling. Multi-break arc breaking: The high resistivity of the constantan wire (about 49μΩ·cm) generates a spiral multi-break arc upon melting. The arc length is 3-5 times longer than that of a solid fuse, accelerating energy dissipation (arc energy reduced by 50%) and shortening the breaking time to less than 5ms (compared to about 20ms for a traditional fuse). Low-resistance main path of the silver fuse: The silver fuse serves as the central conductor (diameter 2-4mm), with a DC resistance of <1mΩ and a temperature rise of <50K during normal operation. When a surge current passes through, the silver fuse melts rapidly (melting point 961℃), while the constantan wire spiral... The structure rapidly vaporizes due to Joule heating, forming a dual-break mechanism. Fatigue-resistant design: The double-helix interlocking structure reduces metal fatigue fracture caused by periodic surges (such as several daily power grid switching operations) through stress dispersion, achieving a lifespan of up to 100,000 impacts (compared to approximately 10,000 for traditional wound fuses). Low-loss operation: Under normal conditions, current is primarily conducted through the silver fuse wire, with the constantan wire carrying only about 5% of the current (because constantan's resistivity is 50 times that of silver). Power loss is <0.5W (at a 100A load), far lower than that of pure constantan resistors (loss approximately 10W). Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a silver fused wire;

[0022] In the diagram: silver fused monofilament-1, constantan wire-2, insulating support ring-3, pin-4. Detailed Implementation

[0023] The present disclosure will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present disclosure are shown in the accompanying drawings.

[0024] Example 1:

[0025] This embodiment provides a silver fusion wire, including a silver fusion monofilament 1, a constantan wire 2, and pins 4. The constantan wire 2 is provided in two strands, which are respectively processed into a left-handed spring shape and a right-handed spring shape. The two constantan wires 2 are respectively wound on the surface of the silver fusion monofilament 1 and staggered. Pins 4 are fixedly connected to both ends of the silver fusion monofilament 1, and the two ends of the two constantan wires are electrically connected to the pins 4.

[0026] In this embodiment, two sets of non-overlapping components are used to achieve staggered arrangement. Silver fuse: The main body is a cylindrical silver conductor with a diameter d1 = 0.5-2mm (adjustable according to the rated current; for example, d1 = 1mm is optional for 10A current). Leads are soldered to both ends; the material is pure copper or silver-plated copper, with a cross-sectional area S. 引脚 ≥2mm^ 2 Used for circuit connection. Constantan wire: made of constantan alloy wire with a diameter d2 = 0.1-0.3mm, containing 55% copper and 45% nickel, with a resistivity ρ = 0.49μΩ·m. It is wound in a double helix structure on the outside of the silver fused wire, forming two sets of helices in opposite directions, one right-handed and the other left-handed, with a pitch p = 0.8-1.5mm and a helix diameter D = d1 + 2d2.

[0027] Calculation of helical structure parameters: Number of turns in a single helix: n = L / P, where L is the effective length of the silver fuse (excluding leads). For example, when L = 10mm and p = 1mm, n = 10 turns. Total resistance of constantan wire: Among them, L 总 L represents the total length of the constantan wire in the double helix structure. 总 ≈2n.πD. For example: n=10, D=1.2mm, then L 总 ≈2X10 X 3.14X1.2=75.36mm, Shunt ratio control: During normal operation, the silver fuse resistor (ρ 银 =1.59×10 -8 Ω·m), split ratio (Because of R) 康铜 >>R 银 It is necessary to ensure that k < 1% (i.e., constantan wire current < 1% x rated current) to avoid overheating during normal operation.

[0028] Double helix winding steps: Fix the silver fused wire on the precision winding machine fixture, and wind a right-hand helix first under constant tension (0.5-1N). After completion, wind a left-hand helix in the opposite direction, ensuring that the two sets of helices are tightly fitted and do not cross. During the winding process, use a microscope (20x magnification) to monitor the uniformity of the pitch, and control the error within a specified range.

[0029] Within ±0.05mm. Lead soldering process: Both ends of the constantan wire are laser-spot-welded to the silver fuse leads (power 5-10W, pulse time 0.1-0.3ms), with a solder joint diameter ≤0.3mm to avoid localized overheating and damage to the silver fuse. A tensile test is performed after soldering; the tensile strength of the solder joint is ≥5N (ensuring it does not detach under vibration).

[0030] Example 2:

[0031] In this embodiment, the silver fused wire further includes an insulating support ring 3, which is fixed to both ends of the silver fused monofilament 1. The two ends of the two constantan wires 1 are fixedly mounted on the insulating support ring 3. The insulating support ring 3 is made of either ceramic or glass fiber. In this embodiment, the overall mechanical strength is increased by mounting the insulating support ring 3, ensuring overall temperature control. A ceramic or glass fiber support ring is provided at each end of the silver fused wire, with an inner diameter equal to the diameter of the silver fused wire and an outer diameter equal to the outer diameter (D) of the spiral structure. This ring is used to fix the spiral shape of the constantan wire. A through groove is provided on the insulating support ring, through which the constantan wire passes and is fixed to the pin.

[0032]

[0033]

[0034] Example 3:

[0035] In this embodiment, nano-sized alumina particles are filled in the gaps of the constantan wire 2 to serve as a buffer. During winding, a tensile prestress of 5%-10% is applied to the constantan wire to maintain tension in the helical structure during vibration and prevent it from loosening. Nano-sized alumina particles (particle size ≤100nm) are filled in the gaps of the helix to reduce the vibration response (amplitude ≤0.1mm when vibration acceleration ≥10g) by utilizing the particle damping effect.

[0036] Example 4:

[0037] In this embodiment, a reversible thermosensitive coating is applied to the surface of the constantan wire. The reversible thermosensitive coating (such as a liquid crystal polymer material) is applied to the surface of the constantan wire, and the color-changing temperature is set to T. 触发 =T 银熔点 +10℃ = 971℃. When the coating melts, it changes from transparent to red. After cooling, it returns to transparent, making it easy to observe multiple times.

[0038] Example 5:

[0039] In this embodiment, the constantan wire is coated with a silicone rubber insulating varnish layer. After winding, a layer of silicone rubber insulating varnish (0.05-0.1mm thick) is coated on the outer layer of the double helix structure. After curing, it forms an elastic insulating layer that has both shockproof and heat dissipation functions.

[0040] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] Those skilled in the art should understand that the above embodiments are merely for illustrating the present disclosure and are not intended to limit the scope of the disclosure. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present disclosure.

Claims

1. A silver fused wire, comprising a silver fused monofilament, characterized in that, It also includes constantan wire, of which two constantan wires are provided, which are respectively processed into a left-handed spring shape and a right-handed spring shape. The two constantan wires are respectively wound on the surface of silver fused monofilament and arranged in a staggered manner.

2. The silver fuse according to claim 1, characterized in that, The silver fused wire also includes leads, and both ends of the silver fused wire are fixedly connected to leads, and the two constantan wires are electrically connected to the leads at both ends.

3. The silver fused wire according to claim 1, characterized in that, The silver fused wire also includes an insulating support ring, which is fixed at both ends of the silver fused monofilament, and the two ends of the constantan wire are fixedly mounted on the insulating support ring.

4. A silver fuse according to claim 3, characterized in that, The insulating support ring is made of either ceramic or glass fiber.

5. A silver fuse according to claim 4, characterized in that, The gaps between the constantan wires are filled with nano-sized alumina particles.

6. A silver fused wire according to claim 5, characterized in that, The constantan wire is coated with a reversible thermosensitive coating.

7. A silver fuse according to claim 5, characterized in that, The constantan wire is coated with a silicone rubber insulating varnish layer.

8. A silver fuse according to claim 4, characterized in that, The insulating support ring has a through groove, through which a constantan wire passes and is fixed to the pin.

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