JPS5853457B2 - High voltage cut-out fuse - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a high voltage cut-out fuse in which a fusible material is stretched between a head terminal and a lead wire, and the outer periphery is surrounded by an arc-extinguishing tube 7" with one end sealed by the head terminal. The purpose is to resolve the cross section of a fusible body ■2
By varying t, the pressure inside the fuse cylinder is controlled, and the inside of the fusible body is made into a cavity, and by filling both the cavity and the outer periphery of the fusible body with an arc extinguishing agent, the arc extinguishing ability is increased and the arc is cut off. The aim is to significantly improve one's abilities.

Most conventional fusible bodies have the same cross-sectional area over their entire length, and the cross section of the fusible body has the same straightness over its entire length.

For this reason, when a large current passes through a short circuit, the entire fusible material becomes gasified in a very short period of time at the beginning of the short circuit, and the pressure inside the fuse cylinder inevitably rises rapidly.This sudden pressure rise and its secondary effects limit the breaking ability. It had been done.

In other words, when a conventional high-voltage cut-out fuse is ignited by a large current, the pressure inside the fuse cylinder rises rapidly, and the fuse cylinder is unable to withstand this shocking pressure rise, and is destroyed and continues to flow, making it impossible to shut off. The arc extinguishing tube may be destroyed by a sudden rise in pressure, reducing arc extinguishing capability, or the arc extinguishing tube may be torn apart or blown out by the sudden release of internally generated gas through the fuse barrel opening. There is a significant decrease in the arc extinguishing ability due to the current flowing, and if the current reaches zero point in this state, it will continue to flow in the fuse cylinder, which will naturally lead to the inability to shut off the fuse.

In addition, when internally generated gas is released to the outside at high speed, a phenomenon can be seen where the gas enters the interior from the bottom of the cutout due to collision with the outside air, but this gas is ionized and has extremely poor electrical insulation. As a result, the dielectric strength between the external electrodes of the fuse cylinder or between the cutout switch electrodes is reduced, and there is a risk that a follow-on current will occur between these electrodes, making it impossible to shut off.

In view of the above points, this invention first involves cutting the cross section of a fusible body.
By changing 2t, a steep rise in internal pressure is prevented, and the shutoff pressure is thereby significantly improved.

That is, the present invention is characterized in that the cross-sectional line of the fusible body gradually decreases toward the connection part with the lead wire, and the straightness of the cleavage 2 t in each cross-section gradually increases toward the head terminal. An example of this is shown in FIG.

In the figure, 1 is a head terminal, 2 is a lead wire, 3 is a flexible body stretched between the head terminal 1 and the lead wire 2, 4 is a fastener, and 5 is a flexible body stretched between the head terminal 1 and the lead wire 2.
is an arc extinguishing tube whose one end is sealed with the head terminal 1 and which surrounds the outer periphery of the fermentable body 3.

The flexible body 3 has a cross-sectional area that matches the rated current of the fuse at point A, and is designed so that the straightness of the sectional area I2t at each cross section increases as it progresses from point A to point B and point 0. The cross-sectional area is changed.

In such a state, when a short-circuit large current is passed, when the passing time 2t coincides with the break I2t at the point A, the point A fires and gas is generated.

Since this point A is close to the opening side, the pressure of the generated gas does not increase much, and therefore the gas is released quickly.

In this case, since the pressure cuff inside the fuse cylinder is slow and the gas release rate is slow, there is no damage to the arc extinguishing tube 5.
In addition, the generated gas is also prevented from entering the interior of the cut-out switch.

However, if the current reaches zero point while the pressure inside the fuse cylinder is low, even if the arc extinguishing tube has sufficient arc extinguishing ability, it may not be possible to interrupt the current, so the , gradually increase the pressure,
Although it is necessary to have a sufficiently large dielectric strength, in this invention, the required dielectric strength is obtained by moving the gas generation position toward the zero point.

That is, since the passage 2 t increases with the passage of time, points having a dissolution 2 t equal to one point of the curve are sequentially gasified, and the point B is reached one after another.

By this time, the fastener 4 and lead wire 2 have been ejected into the fuse cylinder, so the arc electrode is at point B inside the fuse cylinder and outside the fuse. Until this state is reached, the arc electrode in the fuse cylinder has moved from point A to point B, and therefore the gas generation position has also moved from point A to point B.

Here, for example, if the rate of increase of cross section I2t in each cross section between point A and point B is increased, the time required to reach point B from point A becomes longer, and therefore the position of gas generation increases. Your movement speed will be that much slower.

Moreover, if the increase rate of 2 t is reduced, the moving speed can be increased, and the moving speed can be freely adjusted.

Fuse operation ■2 1st shift of t is the break at point B ■2 If t is equal to t, the moving distance of the gas generation position is from point A to point B, and break at point C ■2 When it is equal to t, the moving distance is approximately up to point C, and the moving distance of the gas generation position can also be freely adjusted.

In this way, by locating the gas generation position inside the fuse cylinder,
If the fuse is moved at a certain speed toward the zero point, the pressure inside the fuse cylinder will increase according to the speed of movement, and the rate of increase in pressure can be adjusted, and gas generation will continue until sufficient dielectric strength is obtained at the zero current point. It becomes possible to move the position.

Furthermore, since the fuse cylinder pressure and the arc voltage have an approximately proportional relationship as has been known, it is also possible to freely control the arc voltage.

In other words, it is possible to create the best arc voltage waveform according to the properties of the fuse cylinder and the performance of the arc extinguishing tube, greatly increasing the m capacity of the high voltage cutout fuse, and creating an innovative high voltage cutout fuse. It's something you get.

Furthermore, by controlling the arc voltage waveform, arc energy can be kept low, damage to the arc extinguishing tube and fuse tube can be minimized, and the gas generation position can be changed from point A to point B to point C. During arc generation, fresh arc extinguishing tubes with no deterioration in arc extinguishing ability are constantly located around the gas generation position, which has the advantage of greatly increasing arc extinguishing ability.

In FIG. 2, the arc extinguishing agent 6 is filled in the arc extinguishing tube 5, and with such a configuration, it is possible to further improve the interrupting performance.

That is, similar to the example shown in FIG. 1, the fusible body 3 changes the cross-sectional area so that the straightness of the fusion cut I2t of each cross section increases as it approaches point C, and connects the head terminal ■ and the lead. The arc-extinguishing tube 5 is connected between the wires 2 via a fastener 4, and the arc-extinguishing tube 5 is filled with a powdered arc-extinguishing agent 6.

7 is a stopper for preventing arc extinguishing agent from flowing out. The arc extinguishing agent 6 is not limited to powder, but may be solid as long as it is quickly released.

In addition to the above-mentioned functions and effects, the above configuration has the following effects.

That is, in this example, when an arc first occurs at point A, the arc extinguishing agent 6 near point A immediately cools the arc electrode, and the arc extinguishing powder that has absorbed heat together with the plug 7 is released into the outside air while preventing the growth of the arc. released to.

Since the arc temperature is lowered by this discharge action, the growth of the arc is further suppressed.

When the arc electrode reaches point B, the arc-extinguishing powder from point A to point B has been ejected, but fresh arc-extinguishing powder with no deterioration in arc-extinguishing ability is present near point B. Since it exists, the same effect as at point A can be obtained.

In this way, the same effect as at point A can be obtained throughout the arc generation, from arc initiation to arc extinguishment, and the interrupting ability can be further improved.

FIG. 4 shows an embodiment of the present invention which is a further development of the idea in FIG. 2, in which the inside of the storage body 3 is hollow,
Both the outer periphery of the fusible body and the inside of this cavity are filled with an arc extinguisher 6.

In this way, when an arc extinguishing agent is filled in the cavity inside the fortifiable body, it is less likely to blow away and is more stable than an arc extinguishing agent filled outside. In addition to generating arc gas, the effect of cooling the electrode part is longer lasting than that of an externally filled arc extinguisher, and can exhibit the highest breaking ability.

The arc extinguishing agent filled inside the flexible body may be a liquid one.

Additionally, various methods can be used to manufacture the above-mentioned flexible body, such as winding a plate-shaped material, cutting and forging a bar-shaped material, and drawing a pipe.

Furthermore, FIG. 3 shows another row of fermentable bodies that can also be employed in the configuration of the embodiment of the present invention shown in FIG. An example of partial replacement is shown.

That is, the cross section of the head terminal 1 gradually decreases toward the tip, and the fermentable part 3 that matches the rated current of the fuse is connected between the tip and the lead wire 2.
In this case as well, the above-mentioned points A, B, and C are obtained as shown in the figure, and it is possible to expect the same operation and effect as in the above-described embodiment.

As described above, the present invention gradually decreases the cross-sectional area of the flexible body toward the connection portion with the lead wire, thereby changing the rupture 2 t in each cross section of the flexible body, thereby providing sufficient insulation. In addition to ensuring strength, the interior of the flexible body is hollow and both the outer circumference of the flexible body and the inside of this cavity are filled with arc extinguishing agent, which improves arc extinguishing ability and provides sustainable electrode cooling. Through the synergistic effect of each composition, we were able to eliminate all of the difficulties seen in conventional examples and provide a high-voltage cut-out fuse with significantly improved breaking ability.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the first component of the high voltage cutout fuse according to the present invention, FIG. 2 is a sectional view showing an example of the second component, and FIG. 3 is a sectional view showing an example of the second component. It is a principal part schematic diagram showing the other side. FIG. 4 is a sectional view showing an embodiment of the high voltage cutout fuse according to the present invention. 1・1'... Head terminal, 2... Lead wire, 3... Fermentable body, 3'... Flexible part,
5... Arc extinguishing tube, 6... Arc extinguishing agent.

Claims (1)

[Scope of Claims] 1. A high-voltage cut-out fuse in which a fusible material is stretched between a head terminal and a lead wire, and the outer periphery is surrounded by an arc-extinguishing tube whose one end is sealed with the head terminal; The cross-sectional area is gradually decreased toward the connection part with the lead wire, and the inside of the fusible body is partially or completely hollow, and this cavity is filled with arc extinguishing agent. A high-pressure cutout fuse characterized by being filled with an arc agent. 2. The high-voltage cut-out fuse according to claim 1, wherein the fusible body is composed of a fusible portion that matches the rated current of the fuse and a head terminal that gradually decreases toward the connection portion between the fusible portion.