JPS6217967Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a power fuse with multiple lightning protection measures.

In this type of power fuse, if an abnormal current flows due to an accident or lightning, the fuse element installed inside the outer cylinder will melt, and the arc will be extinguished by the arc extinguishing agent to ensure that the circuit is quickly disconnected. be done. However, if lightning strikes in this state, the dielectric strength inside the fuse is extremely high, so there is a risk of external flashover occurring between the fixed electrodes on the outside of the outer cylinder, and also between the electrodes of the equipment that houses this fuse. It is also possible that a connection may occur. Therefore, there was a risk that the arc energy from the follow-on current would destroy the fuse itself or the equipment inside the fuse due to uneven heat, resulting in a public disaster.

In particular, box-shaped cut-out switches have a structure that prevents the lid from opening even if the fuse blows, and when abnormal voltage is applied due to lightning, etc., the fuse's external electrodes will sparkle, causing a follow-up current. There was a risk that the lid insulator would be damaged by uneven heat due to arc heat.

Therefore, the present invention has a structure in which the abnormal current caused by lightning, etc. after a fuse blows out is caused to flow through the arc-extinguishing agent to the flashing electrode provided inside the fuse and the fixed electrode on one side, and the fuse itself or this fuse is installed inside the fuse. The present invention provides a power fuse that prevents uneven heat damage caused by external flashover in various types of equipment.

Embodiments embodying the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a power fuse embodying the present invention, in which an insulating core 2 is provided at the center of an outer cylinder 1 made of an insulating material such as glass fiber reinforced plastics.
is arranged, and cap-shaped fixed electrodes 3 and 4 are provided at both ends.
A fuse element F is connected between both fixed electrodes 3 and 4 so as to wrap around the insulating core 2.

A resistance wire 5 is disposed inside the insulating core 2 in parallel with the fuse element F, one end of which is attached to the fixed electrode 3, and the other end of which can be protruded out of the fixed electrode 4 by melting the resistance wire 5 (Fig. (not shown) is connected to the fixed electrode 4 via a fusing indicator case 6 that houses a fuse-cutting indicator case 6 (not shown). Incidentally, the outer cylinder 1 and the insulating core 2 are filled with an arc extinguishing agent 7, so that when the fuse element F and the resistance wire 5 are fused, the arc is extinguished by current limiting.

Furthermore, a conductive substance 8 is coated on the inner wall of the outer cylinder 1 on the fixed electrode 3 side, with one end connected to the fixed electrode 3, and the tip 8a of the conductive substance 8 and the inner wall of the other fixed electrode 4 are coated. A gap 1 is provided between the end portion 4a to form a sparkling electrode. Usually, this gap L and the fuse element F and the conductive material 8 are isolated by an arc extinguishing agent 7. Therefore, no flashover occurs between the conductive material 8 and the fuse element F and between the gap L.

Now, let's talk about what happens when a power fuse configured in this way blows out. When an abnormal current flows due to lightning, etc., the fuse element F and then the resistance wire 5 are fused in this order, and the inside of the fuse is completely blown out. At the same time, a fusing indication is displayed. If lightning strikes again, most of the arc extinguishing agent 7 in the outer cylinder 1 will melt when the fuse element blows out earlier, and the gap between the tip 8a of the flashing electrode and the inner end 4a of the fixed electrode 4 will be reduced. The dielectric strength between the gaps is decreasing, and the insulation distance between the fixed electrodes 3 and 4 outside the outer cylinder 1 is much shorter than the distance between the gaps 1 and 1, so all the flashover occurs within the fuse. Priority is given to the area between the gap 1, and the following flow is caused by the residual arc quenching agent 7 in the fuse.
The arc will be extinguished at

Therefore, in the case of abnormal voltage caused by multiple lightning strikes after a fuse element has blown out, by prioritizing all the flashover within the fuse, it is possible to prevent uneven heat damage to the fuse itself or various devices equipped with this fuse due to follow-on current. This can be reliably prevented.

FIG. 2 shows a second embodiment of the present invention, in which an arcing horn 9 is inserted into the arc extinguisher 7 between the inner wall of the outer cylinder 1 and the insulating core 2, with one end connected to the fixed electrode 3 and the other end directed toward the fixed electrode 4. This figure shows a power fuse in which a flashover electrode is formed, and the operation and effect are the same as in the previous embodiment.

FIG. 3 shows a third embodiment of the present invention, showing a power fuse in which a conductive substance 8 is applied to the inner wall of an insulating core 2 to form a flashover electrode, and the operation and effect are the same as in the previous embodiment. .

FIG. 4 shows a fourth embodiment of the present invention, in which an arcing horn 9, one end of which is connected to the fixed electrode 3 and the other end directed toward the fixed electrode 4, is inserted into the arc extinguisher 7 between the inner wall of the insulated core 2 and the resistance wire 5. This figure shows a power fuse in which a flashover electrode is formed, and the operation and effect are the same as in the previous embodiment.

In the embodiment of the present invention, the flashover electrode is provided on one side of the fixed electrode, but it is also possible to provide it on both fixed electrodes facing each other. Further, although an insulated core and a resistance wire are provided in the embodiment of the present invention, these can be removed if the fuser does not have a fusing indicator.

In this way, the present invention is not limited to the above embodiments,
Any changes may be made as appropriate as long as they are within the gist of the present invention.

As described in detail above, the present invention is a simple method in which a sparkling electrode is provided in the arc extinguishing agent in the fuse, at least on one side of the fixed electrode, one end of which is connected to the one side of the fixed electrode, and which is directed toward the other side of the fixed electrode. With this structure, all flashovers caused by abnormal voltages such as multiple lightning strikes after the fuse is blown are given priority to the inside of the fuse, and damage caused by uneven heat to the fuse itself or various devices equipped with this fuse due to follow-on current caused by flashbacks is prevented. This is a device that can be prevented and has many industrial applications.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a first embodiment of a power fuse embodying the present invention. FIGS. 2, 3, and 4 are cross-sectional views showing other examples of power fuses embodying the present invention. DESCRIPTION OF SYMBOLS 1... Outer cylinder, 2... Insulating core, 3, 4... Fixed electrode, 7... Arc-quenching agent, 8... Conductive material, 9...
Arching horn, F...fuse element.

Claims (1)

[Claims for Utility Model Registration] (1) An insulating core is disposed in the center of the outer cylinder, fixed electrodes are fixed to both ends, and a fuse is arranged between the fixed electrodes so that the insulating core is wound. In addition to connecting the elements, a resistance wire is connected in parallel with the fuse element in the same insulating core via a fusing display case with a fixed electrode on one side, and the outer cylinder and insulating core are filled with arc-extinguishing agent. A power fuse, characterized in that one end of the arc-quenching agent is connected to one fixed electrode, and a sparkling electrode facing the other fixed electrode is provided on at least one fixed electrode side. (2) The power fuse according to claim 1 of the utility model registration claim, in which a conductive substance is applied to the inner wall of the outer cylinder to form a flashover electrode. (3) The power fuse according to claim 1 of the utility model registration, wherein an arcing horn is protruded between the insulating core and the outer cylinder to form a flashover electrode. (4) The power fuse according to claim 1 of the utility model registration, wherein a conductive material is applied to the inner wall of the insulating core to form a flashover electrode. (5) The power fuse according to claim 1 of the utility model registration, wherein an arcing horn is protruded between an insulating core and a resistance wire to form a flashover electrode.