JPS5916384B2 - High voltage cutout fuse - Google Patents

Description

Detailed Description of the Invention In this invention, a fusible body is stretched between a head terminal and a lead wire, and the outer periphery of the fusible body is surrounded by an arc extinguishing tube whose one end is sealed with the head terminal, thereby extinguishing the arc. The lead wire led out from the other end of the tube is folded back to the outside at the open end of the fuse cylinder, and the lead wire is attached to the outer wall of the fuse cylinder. This method is related to an improvement of a high voltage cut-out fuse in which the lead wire is connected to an electrode.

Generally speaking, when a short-circuit current is passed through a high-pressure cut-off fuse, the fusible material arcs, turns into gas, and is discharged from the open end of the fuse tube along with the arc-extinguishing gas in the arc-extinguishing tube, completing the interruption. .

However, when the short-circuit current increases, the gas from the fusible arcing becomes hot and high-pressure, and the lead wire inside the fuse tube is gasified and torn off, causing the arc electrode to become disconnected from the head terminal. This is near the lead wire folding position.

Generally, lead wires are stranded wires such as thin copper wires, so the arc heat causes the lead wire attachment to melt in the direction of the electrode, eventually causing the lead wire outside the fuse cylinder to gasify. .

Since the lead wire outside the fuse cylinder is located inside the cutout, gas caused by the melting of the lead wire naturally fills the cutout interior.

Since this gas is ionized and has extremely low electrical insulation, it can significantly reduce the dielectric strength between the fuse cylinder outer electrodes or the cutout electrodes, and prevent arc discharge between these electrodes. I had reached the point where I was unable to function.

Therefore, the purpose of this invention is to suppress the gasification of the lead wire as much as possible when the fusible material arcs, to prevent gas from entering inside the cutout, and to provide a high-pressure cutout with high performance breaking performance. The aim is to provide out-of-use.

In order to achieve the above object, the high voltage cutout fuse according to the present invention is provided with a conductive metal fitting that protrudes downward beyond the folded part of the lead wire led out from the other end opening of the arc extinguishing tube. The present invention is characterized in that the arc electrode at the time of melt ignition is moved to the tip of the protrusion of the conductive metal fitting.

The details will be further explained below according to the embodiments shown in the accompanying drawings.

FIG. 1 shows an embodiment of the conductive metal fitting 1 used in the present invention, in which a cut groove 1a is formed from one end of a metal tube made of copper or copper alloy with a width equal to the thickness of the lead wire. Insert the lead wire 2 into the pipe along the kerf, and
The other end has a structure in which the lead wire is attached to a length that can be connected to the electrode, and the conductive metal fitting 1 and the lead wire 2 are fixed by compression connection or the like.

Figure 2 shows the high voltage cutout fuse attached.

In the figure, 3 is a fusible body, one end of which is connected to the head terminal 4, and the other end connected to the lead wire 2 via a fastener 5.

Reference numeral 6 is an arc extinguishing tube that surrounds the outer periphery of the fusible body 3 and has one end sealed with the head terminal 4, and the other end is open.

FIG. 3 shows the state inserted into the fuse tube 7.

When the head terminal 4 is inserted into the fuse tube 7, it is electrically connected to the upper contact blade 9 through the fuse tube cap 8, and the lead wire 2 led out from the arc extinguishing tube 6 is folded back to the outside at the open end of the fuse tube. The lead wire attachment is connected to the electrode 10 at the terminal portion led out from the conductive metal fitting 1 and is electrically connected to the lower contact blade 11.

In this case, the conductive metal fitting 1 is structured so as to protrude downward beyond the folded portion C of the lead wire led out of the fuse cylinder.

When a short circuit current passes under such conditions, the fusible body 3
When high-temperature, high-pressure gas is released from the fuse tube 7 due to the ignition of the fuse, the lead wire between points A and E in the fuse tube is gasified or torn off and released to the outside. Since gasification continues between point B and point C, the arc electrode becomes the zero point between the head terminal 4 and the lead wire.

However, since the area near point C is close to the gas discharge port, the gas pressure is high, and the blowing of the discharged gas tends to increase the voltage drop at point C of the arc electrode. The arc electrode moves to point E at the tip of the conductive metal fitting 1, and eventually an arc discharge occurs between the head terminal 4 and the point E at the tip of the conductive metal fitting 1.

As a result, the 0 point is no longer an arc electrode, so there is no longer a phenomenon in which the generated gas is guided inside the cutout, and the 0 point is no longer an arc electrode.
Since the lead wire between the points is not gasified, there is no generation of gas inside the cutout.

Note that the arc electrode moves from point 0 of the lead wire to point E of the conductive metal fitting 1, but this point E is also located below the discharge port of the fuse tube 7, so the flow of the emitted gas is directed downward. It also serves as a guide.

Since it is possible to effectively prevent conductive gas from entering inside the cutout, arc discharge between the fuse cylinder external electrodes, that is, between the upper contact blade 9 and the lower contact blade 11, and between the cutout electrodes is prevented. Without this, the shutoff performance is greatly improved.

In the example shown in Figure 4, the lead wire outside the fuse cylinder is folded back to the outside at the open end of the fuse cylinder, and the lead wire attached to the outer wall of the fuse cylinder is connected to the terminal end of the fuse cylinder connected to the electrode and the open end of the fuse cylinder. Three pieces of conductive metal fittings that protrude beyond the folded part of the folded lead wire are integrally formed using conductive material, and the lead wire can be attached to one end of a metal plate, etc. and connected to the electrode. In addition to forming a claw portion 12, a protruding portion 14 is formed through a step portion 13, and a small hole 15 for fixing a lead wire is formed in the step portion 13.

With such a configuration, the work of attaching the lead wire to the electrode is simplified.

In addition, in the example shown in FIG. 5, the protrusion 14 that protrudes beyond the opening end of the fuse tube, that is, the circumferential side from point F to point G in the figure, has a curved surface with no corners, and the end edge of the tip This example has corners, but the other points are the same as the example shown in FIG.

According to the present invention, as described above, the arc electrode is
This method aims to significantly improve the breaking ability by preventing gasification of the lead wire and controlling the flow of released gas by moving the lead wire from the point to the 8 points at the end of the protrusion 14 of the conductive metal fitting. However, as the short-circuit current increases further, the difference between the gas pressure on the circumferential side from point F to point G of the protrusion 14 and the gas pressure at the end 8 points decreases, and the initial arc electrode C
In this case, there is a possibility that the point does not move to point E, but moves to the circumferential side between the point F and point G of the protruding portion 140, and there is a tendency that no further improvement in the shutoff performance can be expected.

However, as shown in FIG. 5, if the circumferential side of the protruding portion 14 is formed into a curved surface with no corners, and the tip end edge is formed with a corner, the discharge starting voltage of the ball gap and needle gap during the discharge phenomenon will be reduced. As can be seen from the difference in , the transition to the angular point E is ensured, and the interrupting performance can be further improved.

The example shown in FIG. 6 is a further development of the above-mentioned idea, in which a needle-like protrusion 16 is provided on the end face, thereby making the transfer of the earth electrode even more reliable.

Furthermore, the example shown in FIG. 7 shows an improved type in which the tip of the protruding portion 14 is bent toward the lead wire side to form an abbreviated shape.

In the previous embodiments, the aim was to prevent gasification of the lead wire portion exposed outside the fuse cylinder, that is, after the 0 point, but in this example, the lead wire located inside the fuse cylinder Part of the line, i.e. in the figure,
It can also prevent gasification between points B and C, and when shutting off, the 8th
As shown in the figure, point B of the lead wire and tip E of the protrusion 14
When the two points come into contact and have the same potential, arc discharge continues, and the interruption is completed at the current zero point.

In other words, when a short-circuit current passes, when high-temperature, high-pressure gas is released from the fuse tube due to the arcing of the fusible material, the area from around point A to around point B of the lead wire is first gasified, and the area around point B becomes an arc electrode. Then, gasification attempts to proceed further toward the 6 points.

At the same time, the lead wire between points B and C tries to be pushed out of the fuse cylinder by the gas pressure, so point B, which serves as an arc electrode, contacts point E of the protrusion 14 while guiding the arc, causing electrical Point E and point B will be integrated.

Therefore, the arc electrode will be at point E on the protruding part and point B on the lead wire, but if the heat capacity at point E is made large enough, there will be almost no melting after that, so the point B - C on the lead wire will be the same. The gap will remain ungasified.

Therefore, in this example, in addition to the above-mentioned functions and effects, it is possible to prevent gasification of the lead wire between point B and point C located inside the fuse cylinder, thereby further improving the breaking performance. It's something you can get.

As described in detail above, the present invention provides a conductive metal fitting on the lead wire exposed outside the fuse cylinder so as to project downward beyond the folded portion of the lead wire, thereby separating the arc electrode from the lead wire. Transfer to the protruding end of the conductive metal fittings,
Since the gasification of the lead wire is suppressed as much as possible and the flow of the emitted gas is also controlled, it is possible to very effectively prevent conductive gas from entering the inside of the cutout.

As a result, we have been able to provide a high-voltage cut-out fuse with much improved breaking performance compared to conventional high-voltage cut-out fuses.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one embodiment of the conductive metal fitting used in the high voltage cutout fuse of the present invention, and FIG. 2 is a side view showing the state in which the metal fitting is attached to the high voltage cutout fuse. Shown in cross section. FIG. 3 is a side view showing a state in which it is attached to a fuse tube, and is partially shown in cross section. FIG. 4 is a perspective view showing another embodiment of the conductive metal fitting, FIG. 5 is a perspective view showing still another embodiment, FIG. 6 is a perspective view showing still another embodiment, and FIG. 8 is a perspective view showing still another embodiment, and FIG. 8 is a perspective view showing its operating state. 1... Conductive gold A, 2-...-! J-do line,
3... Fusible body, 4... Head terminal, 6...
... Arc extinguishing tube, 7 ... Used tube, 1
4... Protrusion.

Claims (1)

[Scope of Claims] 1. A fusible material is stretched between the head terminal and the lead wire, an arc extinguishing tube whose one end is sealed with the head terminal surrounds the outer periphery of the fusible material, and the other end of the arc extinguishing tube is opened. The lead wire is folded back to the outside at the open end of the fuse cylinder, and the lead wire attachment provided on the outer wall of the fuse cylinder protrudes downward beyond the folded part of the lead wire in the high voltage cut-out fuse that is connected to the electrode. A high-voltage cut-out fuse with a conductive metal fitting attached to the lead wire exposed outside the fuse cylinder. 2. The lead wire outside the fuse tube that is folded back outward at the open end of the fuse tube and the lead wire provided on the outer wall of the fuse tube are attached to the lead wire end connected to the electrode and the lead wire that is folded back at the open end of the fuse tube. 2. A high voltage cut-out fuse according to claim 1, wherein three of the conductive fittings protruding beyond the folded portion of the fuse are integrally formed of a conductive material. 3. The peripheral side of the protruding part of the conductive metal fitting that protrudes beyond the folded part of the lead wire has a curved surface shape with no corners, and the edge of the tip part has a corner. High-voltage cut-out fuse as described in section. 4. Claims 1, 2, or 3, wherein the protruding portion of the conductive metal fitting that protrudes beyond the folded portion of the lead wire has its tip bent toward the lead wire side. High voltage cutout fuse.