JPH0443954Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention connects a fuse element between the head terminal and the lower lead wire, houses it in an arc-extinguishing cylinder, and covers the entire body with a covering cylinder made of craft or polycarbonate. The present invention also relates to a high-pressure cut-out fuse in which a stopper for preventing lead wires from hanging down is provided near the opening end of the sheathing tube, and particularly to improvements in the arc-extinguishing tube.

[Prior art] Conventionally, the extinguishing tube of a high-pressure cut-out fuse was
It was common practice to line the inner surface of an asbestos cylinder made by wrapping asbestos paper with a powdered arc-extinguishing agent such as boric acid or aluminum hydroxide mixed with a binder.

Further, in terms of length, it is usually provided over the entire length of the covering tube from the head terminal portion to the open end.

Further, a metal ring stopper is generally used as a stopper for preventing lead wires from sagging.

[Problem to be solved by the invention] However, recently, the harmfulness of asbestos as a material for extinguishing cylinders has been pointed out, and its use should be avoided from the perspective of worker health management. Furthermore, it is no longer possible to expect a stable supply of materials. Therefore, there is a need to provide an arc extinguisher using a new material instead of asbestos.

Further, the stopper for preventing lead wires from sagging is emitted into the atmosphere when a large current is cut off, but the conventional stopper made of metal may cause injury to the human body.

Furthermore, if the arc-extinguishing tube is provided over the entire length of the covering tube, when the fuse blows out, the arc-extinguishing agent on the inside of the arc-extinguishing tube will not only gasify, but also partially turn into carbon and adhere to the inner surface. As a result, if the fusible part or solidified molten metal came into contact with the inner surface of the arc extinguishing cylinder after the fuse was blown, a leakage current would flow due to the carbon, generating heat, which could lead to burnout of the fuse cylinder.

Therefore, the purpose of this invention is to provide a high-pressure cut-out fuse that uses an arc-extinguishing tube that is highly safe and has favorable arc-extinguishing performance in place of the conventional asbestos-made arc-extinguishing tube. In addition, the present invention aims to provide a high-pressure cut-out fuse that has a stopper made of non-metallic material to safely prevent lead wires from sagging, and furthermore, is designed to provide a high-pressure cut-out fuse that is free from the risk of causing the above-mentioned burnout accident when the fuse melts. It attempts to provide a high voltage cut-out fuse.

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the high-pressure cut-out fuse according to this invention, first, the arc-extinguishing tube has the following configuration.

In other words, it consists of a noncombustible paper cylinder in which 60 to 90% by weight of aluminum hydroxide is held in cellulose fibers, and a boric acid lining applied to the inner surface of this cylinder. The length is such that the fusible part of the fuse element can be extracted from the end of the arc-extinguishing cylinder.

In addition, as an improved structure of the stopper for preventing lead wires from hanging down, the stopper is composed of a fluororesin tube and an adhesive ring fitted around the outer periphery of this tube, and the fluororesin tube has a folded piece to the outer periphery of the adhesive ring. The adhesive ring is adhesively fixed to the vicinity of the opening end of the covering tube.

[Function] As shown in the DTA (differential thermal analysis) chart shown in Figure 3, the noncombustible paper that makes up the arc extinguisher gradually releases moisture from the point where it exceeds 200°C, and when it reaches 300°C. The reaction is almost complete at the point where it exceeds . On the other hand, as shown in FIGS. 4 and 5, conventional asbestos paper and kraft paper do not release moisture, gradually generate heat, and burn rapidly at a temperature of around 300°C.

The above-mentioned characteristics of noncombustible paper are due to the crystallization water of aluminum hydroxide, which greatly contributes to the arc-extinguishing effect.

In addition, such noncombustible paper is non-polluting, has good adhesion to boric acid, has good electrical insulation and heat resistance, and has a stable supply of materials, so it is ideal as an arc extinguishing cylinder material.

In addition, as mentioned above, the length of the extinguishing tube is set so that the fusible part of the fuse element can be pulled out from the end of the extinguishing tube when the fuse is operated, so even if carbon adheres to the inside of the extinguishing tube, However, there is no risk of burning due to heating due to leakage current.

Furthermore, if the stopper for preventing the lead wires from hanging down is composed of a fluororesin tube and an adhesive ring, the fluororesin tube that pops out when the wire is cut off becomes a very light ejected substance, so there is no risk of injury to the human body.

[Embodiment] Fig. 1 shows an embodiment of the high-voltage cut-out fuse according to this invention, in which a fuse element 3 is connected between the head terminal 1 and the lower lead wire 2, and the internal It has a general structure in which the entire body is covered with a covering cylinder 5 made of polycarbonate. In this invention, the arc extinguishing cylinder 4 is made of a noncombustible paper cylinder 4a made of cellulose fibers holding 60 to 90% by weight of aluminum hydroxide, and a boric acid lining 4b applied to the inner surface of the cylinder. It is composed of

As shown in the figure, the fuse element 3 includes a fusible part 3a made of a low melting point alloy, a resistance tube 3b connected to both ends of this fusible part, and a head terminal 1 that passes through the fusible part and the resistance tube. and a tensile strength wire 3c connected to the lead wire 2, forming a so-called combination fuse.

The arc-extinguishing tube 4 covers the lower part of the head terminal 1 and the fuse element 3, and ends considerably shorter than the open end of the covering tube 5, so that the fusible part 3a of the fuse element 3 is pulled out from the end of the arc-extinguishing tube when the fuse is operated. The length is as long as you want.

That is, the length from the upper end of the fusible part 3a to the rear end of the fastener 6 is L1, the length from the end of the arc extinguishing cylinder to the front end of the stopper 7 for preventing the lead wire from hanging down is L2, and the length from the fastener 6 to the front end of the stopper 7 for preventing the lead wire from hanging is L2. If the length to the front end of the stopper 7 is L3, the configuration may be such that the condition L3>L2>L1 is satisfied. Comparing the length of the arc-extinguishing tube 4 and the length of the covering tube 5, the length of the arc-extinguishing tube is about 30% to 50% of the length of the covering tube 5.

The stopper 7 for preventing the lead wire from sagging is
As shown in FIGS. 2A and 2B, it consists of a combination of a fluororesin tube 7a and an adhesive ring 7b made of, for example, hard vinyl chloride. It has a structure in which it is adhesively fixed near the opening end of the covering tube 5 on the outer peripheral wall of the adhesive ring 7b.

In other symbols in the drawings, 8 indicates head terminal 1
9 is an arc-extinguishing tube holder attached to the inner end of the head terminal 1; 10 is a fusible portion 3a;
11 is a display label adhered to the outer peripheral surface of the covering tube 5, and 12 is a color-coded display piece.

[Effects of the invention] The high-voltage cut-out fuse according to this invention has the following effects:
As mentioned above, the arc-extinguishing cylinder is made of a non-combustible paper cylinder and boric acid lined with it, so it is not as harmful as conventional asbestos, does not interfere with work, and has the same performance as non-combustible paper. Therefore, in addition to improving the arc-extinguishing effect, it also has good electrical insulation and heat resistance, as well as stable material supply, making it possible to create a high-pressure cut-out fuse with an extremely effective arc-extinguishing tube structure. be.

In addition, the length of the arc extinguishing cylinder is set to such a degree that the fusible part can slip out from the end of the arc extinguishing cylinder during fuse operation, so even if carbon adheres to the inner surface of the arc extinguishing cylinder, leakage current will not occur. The structure is designed to prevent burnout accidents.

Furthermore, the stopper to prevent the lead wires from sagging is constructed from a combination of a fluorine resin tube and an adhesive ring, so the sliding effect of the fluorine resin not only makes the fuse operation smoother, but also prevents the fuse from sagging when a large current is interrupted. Even if the resin tube were to fly out, the ejected material would be very light, so a high-pressure cut-out fuse with a highly safe stopper that would not cause injury to the human body could be achieved. Furthermore, this fluororesin tube has heat resistance, and from this point of view as well, it is ideal as a stopper.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing an embodiment of the high-voltage cut-out fuse according to the invention, and Fig. 2 shows an embodiment of a stopper for preventing lead wires from sagging used in the high-voltage cut-out fuse. A is a front view, B is a side view, Figure 3 is a DTA curve diagram of the noncombustible paper used in the arc extinguishing tube of the same high-pressure cut-out fuse, and Figures 4 and 5 are the conventional arc extinguishing tube. Asbestos paper and kraft paper as materials
It is a DTA curve diagram. 1...Head terminal, 2...Lower lead wire, 3...
Fuse element, 3a... Fusible part, 4... Arc extinguishing tube, 4a... Noncombustible paper cylinder, 4b... Boric acid lining, 5... Covering tube, 7... Stopper, 7a...
Fluorine resin tube, 7b...adhesive ring.

Claims (1)

[Scope of claims for utility model registration] (1) A fastener 6 between the head terminal 1 and the lower lead wire 2
The fuse element 3 is connected through the arc extinguishing tube 4, and the entire body is covered with a covering tube 5 made of kraft or polycarbonate, and a stopper 7 is provided near the open end of the covering tube to prevent the lead wire from hanging down. In the cut-out fuse, the arc-extinguishing cylinder 4 consists of a cylinder made of non-combustible paper in which 60 to 90% by weight of aluminum hydroxide is held in cellulose fibers, and a lining of boric acid applied to the inner surface of this cylinder. The length L1 from the upper end of the fusible part 3a of the element 3 to the rear end of the fastener 6, and the length L from the lower end of the arc extinguisher 4 to the front end of the stopper 7 for preventing lead wires from hanging down.
2 and the length L3 from the fastener 6 to the front end of the stopper 7 is set to L3>L2>L1 so that the fusible part 3a of the fuse element 3 can be pulled out from the lower end of the arc extinguisher 4 when the fuse is operated. A high-pressure cut-out fuse. (2) The stopper to prevent the lead wire from hanging down is
Consists of a fluororesin tube and an adhesive ring fitted around the outer periphery of this tube.The fluororesin tube has a folded piece to the outer periphery of the adhesive ring, and is adhesively fixed near the opening end of the covering tube in the adhesive ring. A high pressure cutout fuse according to claim 1.