JPS6325651Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement of a current-limiting fuse tube for a cylindrical cutout, which is housed and held within the porcelain body of the cylindrical cutout. The main part is made to hang down and protrude outward from the lower end opening of the porcelain body, thereby separating the upper electrode of the fuse tube from the upper fixed electrode of the cutout, and at the same time, quickly dissipating the heat generated in the fuse tube to the outside of the porcelain body. This invention relates to a drooping type current limiting fuse tube structure that allows for clear indication of fusion even when dissipating it.

In high voltage distribution lines, cylindrical cutouts are used to protect the primary side of transformers. In recent years, this cylindrical cutout has replaced the conventionally used discharge type fuse with current-limiting fuses, which are silent and have a large breaking capacity, especially for pole-mounted transformers in urban areas and transformers in substations inside buildings. It is used for protection such as By the way, the current-limiting fuse used above is based on a general current-limiting fuse that is used by incorporating it into a disconnector or switch, but the shapes of the upper and lower electrodes are partially changed to create a cylindrical cutout. It is made applicable to

The current limiting fuse tube is held vertically within the porcelain main body with its upper electrode in contact with the upper fixed electrode of the cutout and its lower electrode in contact with the lower fixed electrode of the cutout.

However, the above-mentioned current-limiting fuse tube has a so-called non-dripping structure in which the upper electrode of the fuse tube does not separate from the upper fixed electrode of the cutout even if the fuse blows or is cut off. A high voltage is continuously applied between the upper and lower electrodes of the cylinder.

Therefore, if the insulation recovery between the upper and lower electrodes is insufficient after the above operations (melting and shutting off), a leakage current will flow between the two electrodes, causing burnout of the insulating cylinder or even thermal breakdown. In addition to the problem, the arc heat generated at the time of shutoff is prevented from dissipating because the insulating tube remains in the porcelain body even after the shutoff as described above, and the insulating tube remains heated to a high temperature. There was a problem in that the insulation could not be recovered and the insulation tube and other members on the cutout side would eventually burn out or be destroyed by heat.

In addition, the current-limiting fuse tube is equipped with a display device in the insulating tube that informs you of the blown or cut-off state of the fuse (generally, it is located inside the cap terminal at one end of the insulating tube, that is, the lower end). ), but in the past there were problems in that the display portion was small and the protrusion of the display portion was too small, making it difficult to see from a distance.

The present invention is intended to solve these various drawbacks.The upper fixed electrode 2 is fixed to the upper part of the cylindrical porcelain body 1 whose upper end is closed, and the lower fixed electrode 3 is fixed to the lower part of the cylindrical porcelain body 1. The upper electrode 7 of the current-limiting fuse tube 6 is brought into contact with the upper fixed electrode 2, and the lower electrode of the current-limiting fuse tube is brought into fixed contact with the lower fixed electrode 3 on the main body side, so that the fuse tube is inserted vertically into the main body. The upper electrode 7 of the current limiting fuse tube 6 is integrally fixed to the upper part of the insulating tube 9 of the fuse tube, and the lower electrode 8 is slidable on the lower outer periphery of the insulating tube. and an engaging portion 7a is provided on the outer surface of the upper electrode 7, and an engaging flange 8e is provided on the inner periphery of the lower electrode 8, and the upper surface of the inner engaging flange 8e is provided with the engaging portion 7a. A coil spring 24 is engaged with the insulating tube 9 to urge the insulating tube 9 in the projecting direction, and a core body 10 is installed at the center of the insulating tube 9.
The operating plate 18 has the other end of the high-resistance wire 16 accommodated in the interior and connected to the upper electrode 7 rotatably supported by an insulating cover 17 attached to the lower end of the insulating tube 9. It is characterized in that it is connected to the lower electrode 8 via.

Examples of the present invention will be described below.

The main body side of the illustrated cylindrical cutout has a structure that is no different from the conventional structure, and a cylindrical porcelain main body 1 whose upper end is closed and whose lower end is open has a tulip-shaped upper fixed electrode 2.
A lower fixed electrode 8 is fixedly provided at the lower part, and an arc extinguishing device consisting of an arc extinguishing chamber 4 and an arc extinguishing rod 5 is provided between the electrodes 2 and 8.
Reference numeral 6 designates a current-limiting fuse cylinder which is held vertically within the main body 1 with the upper electrode 7 in contact with the upper fixed electrode 2 on the main body side and the contact portion 8a of the lower electrode 8 in contact with the lower fixed electrode 3 on the main body side. crystallized glass or
A core body 10 made of alumina porcelain and having a relatively small diameter is arranged at the center inside the insulating cylinder 9 made of FRP or the like. The core body 10 also has a ribbon-shaped fuse element 1 made of silver with notches formed at appropriate intervals.
1 is wound. One end of the fuse element 11 is connected to the connection plate 13 of the connection fitting 12 at the upper end of the insulating tube 9 by soldering or the like, and the other end is connected to the lower end opening 9a of the insulating tube 9 so that the outer peripheral surface of the insulating tube 9 is closed. A plurality of contact tongue pieces 14 are attached to the circumferential surface that is fitted and fixed to 9b.
A is connected to an integrally formed cap fitting 14 by soldering or the like. Reference numeral 15 denotes a fixing metal fitting for fitting the lower end of the core body 10 to fix the concentric body 10 at the center of the insulating tube 9, and is integrally connected to the center of the inner surface 14b side of the cap metal fitting 14. . 16
is a coiled high resistance wire housed in the core body 10, one end of which is connected to the upper electrode 7 via the connection plate 13, and the other end is led out through the small hole 15a of the fixing fitting 15 and further led out. The portion is folded back and passed through two small holes 17a formed on the side circumferential surface of a synthetic resin insulating cover 17 that is integrally attached to the outside of the cap metal fitting 14 that is fitted and fixed to the outer circumference of the lower end of the insulating tube 9. After locking, move plate 1
The rotation of the plate 18 is restricted by tying it to the connection hole 18a at one end of the plate 8. Reference numeral 19 denotes a stopper for preventing the high resistance wire 16 inside the core body 10 from being pulled out any further, and the stopper fixed to the resistance wire 16 engages with the inner surface of the fixing metal fitting 15 to prevent it from being pulled out. be done.

Further, 18 is an operation plate formed in an oval shape,
The other end of the plate 18 is pivotally attached to an extension 17b of the insulating cover 17 projecting below the cap fitting 14 through a shaft 20, and is configured to rotate around the same shaft 20.

Note that the operating plate 18 may be provided with a spring to ensure clockwise rotational movement.
21 has a hook portion 21a at one end engaged with a notch 18b formed on the pivoting side of the operating plate 18, and the other end is connected to a connecting bolt 22 implanted on the outer peripheral surface of the auxiliary contact portion 8b of the lower electrode 8. This is a connecting piece made of stainless steel or phosphor bronze connected by a nut 23, and prevents the movement plate 18 from rotating in the counterclockwise direction. Reference numeral 8 denotes a cylindrical lower electrode that is slidably fitted to the outer circumference of the lower part of the insulating tube 9, and it contacts the lower fixed electrode 3 on the main body 1 side and continues to move the fuse tube 6 in the vertical direction even after the fuse is blown or cut off. an upper connecting part 8a that is held in place, an auxiliary contact side 8b that extends the contact part 8a further downward, the above-mentioned connecting bolt 22 that is located between the two and protrudes from the outer peripheral surface 8c, and the same bolt. The nut 23 screwed into the fuse tube 6 is inserted into and removed from the main body 1 to open and close the electrical circuit, and also the fitting fitting for the insulated operating rod (especially when replacing the fuse tube 6) An attachment/detachment step 8d and a protrusion 8e' that fit into the outer peripheral surface (not shown) are formed on the outer circumferential surface. 24
is an engaging inner flange 8e of the lower electrode 8 formed to protrude inwardly.
and a locking step 9 integrally formed on the outer peripheral surface of the insulating cylinder 9.
This is a protruding device made of, for example, a coil spring, which is wound around the outer circumferential surface of the insulating cylinder 9 between C and C. The coil spring 24 of the device is a protruding device that is wound around the outer circumferential surface of the insulating tube 9 between In this case, the contact holding force between the upper electrode 7 of the fuse tube 6 and the upper fixed electrode 2 on the main body side, the contact tongue piece 14a of the cap fitting 14 of the fuse tube 6, and the auxiliary contact portion 8b of the lower electrode 8 ( In reality, the spring force (biasing force) is set to be greater than the sum of the contact holding force between the contact portion and the inner surface 8b').

In this case, as a matter of course, care is taken to prevent the spring force from being too large and inadvertently cutting the lead-out portion 16a of the high resistance wire 16. Reference numeral 25 denotes arc-extinguishing sand made of silica sand, quartz sand, etc., filled in the insulating cylinder 9, and is filled around the fuse element 11 and the high resistance wire 16.

Next, the operation of the fuse tube 6 will be explained.

In the above configuration, the load (energization) current is transmitted from the upper fixed electrode 2 of the cutout body 1 to the upper electrode 7 of the fuse tube 6 - the connection fitting 12 - the connection plate 13 - the fuse element 11 - the fixing metal fitting 15 - the cap metal fitting 14 - the cap metal fitting. 14 contact tongue pieces 14a-
Electricity is supplied through a circuit extending from the auxiliary contact portion 8b of the lower electrode 8 to the contact portion 8a to the lower fixed electrode 3 of the cutout body 1.

In this case, the state of the fuse tube 6 is as shown in Fig. 1 and 3.
4, 5, and 6.

Next, if an excessive current flows through the circuit due to an accident or the like, the fuse element 11 will vaporize uniformly over its entire length, and the generated metal vapor will diffuse into the arc-extinguishing sand 25, and the arc energy will be absorbed by the sand. The arc is absorbed and extinguished. At the same time, this fault current flows through the high resistance wire 16 connected in parallel with the fuse element 11 immediately after the element melts, causing the same resistance wire to melt. In this case, the resistance wire 16 is
At its lower part, a portion 16a led out from the small hole 15a of the fixing metal fitting 15 is connected to the operating plate 18, and the operating plate 18 is further connected to the lower electrode 8 via a connecting hook 21 that is hooked to a cutout 18b at the other end. Because of the structure, the portion where the resistance wire 16 is fused receives the spring force of the coil spring 24, and the fusion occurs at the lead-out portion 16a where heat is not removed by the arc-extinguishing sand 25 like in the core body 10. do. Therefore, the operating plate 18 is rotated clockwise about the shaft 20 by the coil spring 24, and the cutout 18b of the plate is disengaged from the hook portion 21a of the connecting piece 21.

By releasing this latch, the above spring force (biasing force)
1 is a contact point A between the inner surface 8b' of the auxiliary contact portion 8b of the lower electrode 8 and the contact tongue piece 14a of the cap fitting 14, and a contact point A is the contact point A between the upper electrode 7 of the fuse tube 6 and the upper fixed electrode 2 on the main body side of the cutout. and release both of them from their contact holding state at the same time.
In this case, the lower electrode 8 of the fuse tube 6 is slidably fitted to the outer periphery of the lower end of the insulating tube 9 as described above. The contact portion 8a of the main body 1
It hangs downward while remaining in contact with the fixed electrode 3 on the side. In the hanging fuse tube 6, an engaging portion 7a formed at the upper part of the upper electrode 7 engages with an inner engaging flange 8e of the lower electrode 8.

As shown in FIGS. 2 and 1, the main parts of the fuse tube 6, such as the insulating tube 9, except for the upper and lower electrodes 7 and 8, are exposed to the outside from the lower end opening 1a of the main body 1, and the fuse tube 6 is Finishes the fusing or cutting operation.

The present invention has the above-described structure, and when the fuse is blown or cut off, the coil spring 24 causes the fuse tube 6 to connect the engaging portion 7a provided on the upper electrode 7 of the fuse tube 6 to the lower electrode 8. The main body 1 of the fuse tube 6 is cut out so that it protrudes downward until it engages with the inner engagement flange 8e.
It is greatly exposed to the outside from the lower end opening 1a. Therefore, the insulating cylinder 9 and the arc-extinguishing sand 25 inside the insulating cylinder
Even when the insulating tube 9 is heated to a high temperature, the heat is quickly dissipated to the outside air, so there is no risk of burning out the insulating tube 9 or even breaking it due to uneven heat as in the conventional case. In addition, since the fuse tube 6 hangs down and protrudes when the fuse is blown or cut off as described above, the upper electrode 7 of the fuse tube 6 is naturally separated from the upper fixed electrode 2 of the cut-out main body 1. High voltage is not applied continuously,
Even if the insulation resistance after the interruption is insufficient, leakage current will not flow and cause another flashover or burnout.

Furthermore, when the fuse is blown or cut off, the main part of the fuse tube is exposed to a larger extent than the main body 1, so this also becomes an indication that the fuse is blown, making the display state easier to see, making it highly practical.

In addition, in the embodiment of the present invention, the structure of the main body 1 of the cylindrical high-voltage cutout is a leadless type, and the lower end of the main body 1 is open. It is also possible to use a salt-resistant type with a resin lower cover and a lid that can be closed by snapping, as shown in FIGS. 10 and 11.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing a main part of a cylindrical cut-out with a current-limiting fuse tube, which is an embodiment of the present invention, and Fig. 2 is a longitudinal cross-sectional view showing the state when the fuse of the fuse cylinder in Fig. 1 is blown. 3 is a half-sectional view showing the contact state between the lower electrode of the fuse tube and the lower fixed electrode on the main body side in FIG. 1, and FIG. 4 is a longitudinal sectional view of the current-limiting fuse tube in the embodiment of the present invention. This shows the state before the fuse blows. Figure 5 is an enlarged sectional view of the lower part of the current-limiting fuse pipe in Figure 4, Figure 6 is a side view of Figure 5 as seen from the side, and Figure 7 is a portion showing the state when the fuse is blown. External view of current limiting fuse tube with rupture, No. 8
The figure is an enlarged sectional view of the lower part of the current limiting fuse tube showing the state after the fuse has blown out, Figure 9 is a side view of Figure 8 viewed from the side, and Figure 10 shows another embodiment of the present invention. 11 is an external view of the lower part of the cylindrical cut-out of the salt-resistant current limiting fuse shown in FIG. 10, showing the state before the fuse is blown. FIG. DESCRIPTION OF SYMBOLS 1... Cylindrical porcelain body, 1a... Lower end, 2... Upper fixed electrode, 3... Lower fixed electrode, 6... Current limiting fuse tube, 7... Upper electrode, 7a... Engaging portion, 8... Lower electrode, 8e... Engaging Inner tsuba, 9...insulating tube, 24...coil spring.

Claims (1)

[Scope of utility model registration request] An upper fixed electrode 2 is fixed to the upper part of a cylindrical porcelain body 1 whose upper end is closed, and a lower fixed electrode 3 is fixed to the lower part thereof, and the upper electrode 7 of the current limiting fuse tube 6 is connected to the upper fixed electrode 2 on the main body side. The lower electrode of the current-limiting fuse tube is fixedly brought into contact with the lower fixed electrode 3 on the main body side, and the fuse tube is housed and held vertically in the main body, in which the current-limiting fuse tube 6 The upper electrode 7 of is fixed integrally to the upper part of the insulating tube 9 of the fuse tube,
Further, the lower electrode 8 is slidably fitted to the lower outer periphery of the insulating cylinder, and the outer surface of the upper electrode 7 is provided with an engaging portion 7.
a, and an engaging flange 8e is provided on the inner periphery of the lower electrode 8, and the upper surface of the inner engaging flange 8e corresponds to the engaging portion 7a. The biasing coil spring 24 is engaged, and the other end of the high-resistance wire 16, which is accommodated in a core body 10 installed in the center of the insulating tube 9 and whose one end is connected to the upper electrode 7, is connected to the insulating tube. An operating plate 1 rotatably supported by an insulating cover 17 attached to the lower end of 9.
A cylindrical cut-out current-limiting fuse tube, characterized in that it is connected to a lower electrode 8 through a cylindrical cutout.