JPS6328511Y2 - - Google Patents

Description

[Detailed description of the invention] The invention consists of a fuse element in which a low melting point alloy part and a silver wire part are connected in series, and an arc extinguishing tube is placed over the outer periphery of the low melting point alloy part, and the fuse element is housed in an insulating tube. The purpose of this project is to improve a current-limiting fuse for full-area high-voltage cut-out, in which both ends of the stored element are connected to the upper and lower electrodes of an insulating tube, and the insulating space of the insulating tube is filled with arc extinguishing agent. In the original application, in order to install the fuse element 5 in the center of the insulating cylinder 1, one end of the winding core 2 is engaged with the upper electrode 7, and the lower cover of the display storage case is fixed to the other end of the winding core. However, in the present invention, exposure of the live part at the lower end of the insulating tube is prevented as much as possible, and the display body is reliably projected out of the lower cover when the fuse is cut off. The purpose is to suggest fuses that can be displayed. Examples of the present invention will be specifically described below. The purpose of this project is to insulate the insulating tube by the voltage applied between the lower electrode and the silver wire section that remains as the large current interrupting section when a low-magnification current flows and the small current interrupting section of the fuse element is interrupted. This is an attempt to propose a current-limiting fuse that will not be destroyed. In other words, a fuse element 5 in which a low melting point alloy part 3 and a silver wire part 4 are connected in series and an arc extinguishing tube 20 is placed over the outer periphery of the low melting point alloy part 3 is spirally wound and hermetically stored in the interior of the fuse element 5 . A current limiting fuse for full-area high-voltage cut-out, in which both ends of the element are connected to upper and lower electrodes 7 and 8 fixed to the upper and lower outer peripheries of the insulating tube 1, respectively, and an arc extinguishing agent 6 is filled in the insulating space 1b of the insulating tube 1. , the fuse element 5 and the lower electrode 8 are interposed to connect them, and the lower end outer surface 1
A conductive plate 17 provided extending upward along d
On the other hand, the outer surface 1d of the lower end of the insulating cylinder 1 covers the same plate.
A bag-shaped lower cover 16 is attached to the bag-shaped lower cover 16, and a small display hole 16c provided at the center of the lower end 16a of the cover 16 is housed inside the display storage case 13, and is always urged in the pop-out direction. The present invention relates to a current-limiting fuse for full-area high-voltage cut-out, characterized in that a display body 14 having a rounded tip 14b is fitted to such an extent that the tip 14b of the display body 14 is not exposed to the outside of a cover 16. Reference numeral 1 denotes an insulating cylinder made of inorganic glass or alumina porcelain, and inside the cylinder there is a winding core 2 made of cordierite or alumina sintered body, and a winding core 2 that extends spirally over its entire length against the outer peripheral surface 2a of this winding core 2. A fuse element 5 is wound. The fuse element 5 has a low melting point alloy part 3 and a silver wire part 4.
The outer peripheral surface of the low melting point alloy portion 3 is covered with an arc extinguishing tube 20. 2
Reference numeral 1 indicates glass fiber seal plugs inserted into the openings 20a at both ends of the arc-extinguishing tube 20 to prevent the arc-extinguishing agent 6 from entering the tube. The winding core 2 and the fuse element 5 having the above configuration have an upper electrode 7 in which the low melting point alloy portion 3 covered with the arc extinguishing tube 20 of the element 5 is fixed to the upper and lower outer peripheries of the insulating cylinder 1.
After these are housed, the insulating space 1b inside the insulating tube 1 is filled with an arc extinguishing agent 6 made of silica sand, quartz, etc. be done. Reference numerals 7 and 8 denote an upper electrode and a lower electrode with insertion blades fixed to the upper and lower outer peripheries of the insulating cylinder 1, and the upper end opening 7b of the upper electrode 7 has a lug-shaped guide fitting fitted to the upper end of the winding core 2. 22
The locking portion 22a is locked to the tapered inner wall surface 7c, so that the winding core 2 is supported at the center within the insulating cylinder 1. Reference numeral 9 denotes a resistance wire for display disposed within the hollow winding core 2, and one end of the resistance wire 9 and the silver wire portion 4a are connected via a heat insulating cushion material 10 such as asbestos that closes the opening 7b. A plate-shaped metal cap 1 that is led out to the outside and is closely attached to the outside.
1 and connected to the upper electrode 7. 12 indicates the solder. Reference numeral 13 denotes a display storage case made of an insulating member (synthetic resin) located at the lower end of the insulating tube 1, and the case includes a guide portion 13a provided at one end of the case that protrudes in the axial direction. 2b, and are directly connected to extend the same winding core 2 in the axial direction. Reference numeral 9 denotes a resistance wire for the display body disposed inside the winding core 2. The wire is once connected to the display body 14 housed in the display storage case 13, and its remaining length is connected to the fuse element 5.
It is connected to one end 17a of the conductive plate 17 together with the silver wire portion 4. A display spring 15 is interposed in a compressed state between the locking step 14a of the display 14 and the upper end 13b of the storage case 13, and always urges the display 14 in the pop-out direction (downward). Reference numeral 17 designates a conductive plate that is clamped and fixed between the insulating tube and the lower cover 16 when the lower cover 16 is attached to the insulating tube 1, and is located at one end 17a of the conductive plate and connected to the silver wire portion 4 as described above. The other end 17b extending upward from the lower end of the insulating cylinder 1 along the lower end outer surface 1d is connected to the lower electrode 8 by a screw 18. Reference numeral 16 denotes a bag-shaped lower cover which covers the outer surface 1d of the lower end of the insulating tube 1 so as to cover the conductive plate 17, and the rear end 16a has an engaging recess 16b and a small hole 16c for display in the center of the rear end 16a. The inner engagement recess 16b is fitted into the lower end 13c of the storage tube 13, and the display body 14 is formed in the display body small hole 16c with a rounded tip 14b. It is fitted into the small hole 16c to the extent that it does not occur. Reference numeral 19 denotes a pipe-shaped insulating heat insulating member made of asbestos or the like, which is interposed between the inner wall surface 1a of the insulating tube 1 and the fuse element 5 so as to cover the arc extinguishing tube 20. The purpose is to insulate the inner wall surface 1a of the insulating tube 1 of the high-resistance material generated by the arc-extinguishing agent 6 and to ensure the withstand voltage between the silver wire portion 4 and the lower electrode 8 after the low current is cut off. It is something. Note that the insulating heat-insulating member 19 is further interposed between the inner wall surface 1a of the insulating cylinder 1 and the display housing case 13 to cover the housing cylinder 13; The high-resistance material is interposed for heat insulation so that it does not come into contact with the inner wall surface 1a of the insulating cylinder 1. Now, in the fuse with the above configuration, if a fault current flows and it is a large current, the fuse element of the fuse will instantly arc over its entire length, and the generated arc will diffuse into the arc extinguishing agent and cause a high current. A resistive material is produced, which restores the insulation and completes the interruption. In this case, a high-temperature, high-resistance material is generated by the arc and the arc extinguisher, but the resistor material is brought into direct contact with (reaches) the inner wall surface 1a of the insulating cylinder 1 by the insulating heat-insulating member 19. Since this is prevented, the insulating cylinder will not be locally overheated and will therefore not be destroyed by uneven heat. In this case, when the fuse element 5 blows out, the same current flows through the display resistance wire 9 connected in parallel with the fuse element 5 , so the resistance wire 9 subsequently blows out, and as a result, it constantly moves in the pop-out direction. The biased display body 14 is pushed into the display body small hole 16 of the lower cover 16 by the display spring 15.
It pops out from c and indicates a fuse or blown. Furthermore, during display, the locking step portion 14a of the display body 14 is locked in the engagement recess 16c of the lower cover 16, and the display body 14 is prevented from protruding too far. Next, if the fault current is small, the low melting point alloy part 3
The arc extinguishing tube 20 placed over the alloy part 3 is thermally decomposed by the heat generated by the arc to generate arc extinguishing gas, thereby extinguishing the arc and interrupting it. Incidentally, the display body projects in the same manner as above to indicate that the fuse has blown. The present invention has the above configuration, and as a result of attaching the bag-shaped lower cover 16 to cover the conductive plate 17 provided at the lower end of the insulating tube 1, the fuse (tube) can be attached to and removed from the cutout. It can be done safely. In addition, the lower end of the fuse is slightly protruded from the main body of the cut-out (when using the fuse attached to the cut-out, in order to make it easier to see the blown state of the fuse, in a general cut-out, the display side of the fuse is placed in the opening of the main body). ) is also safe.
Further, the lower cover 16, which is attached to cover the live part, is provided with a small hole 16c for a display body located in the center of the rear end 16a, and the small hole 16c
In contrast, the tip 1 is installed inside the display storage case 13.
The tip 1 of the display body 14 in which 4b is formed into a rounded shape
4b is fitted so as not to be exposed outside the lower cover 16, so that the display body 14 is not exposed to the outside of the lower cover 16.
This is a practically effective device because it allows accurate fusing display to be performed without any hindrance to its pop-out operation once it is caught in the indicator hole 16b.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a full-area high-voltage cutout current-limiting fuse showing an embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view showing a fuse element. DESCRIPTION OF SYMBOLS 1... Insulating cylinder, 1a... Inner wall surface, 3... Low melting point alloy part, 4... Silver wire part, 5 ... Fuse element, 6... Arc extinguishing agent, 7... Upper electrode, 8... Lower part Electrode, 14...Display body, 14b...Tip, 16...
... lower cover, 16a ... rear end, 16c ... small hole for display body, 19 ... insulating heat insulating member, 20 ... arc extinguishing tube.

Claims (1)

[Scope of utility model registration request] The low melting point alloy portion 3 and the silver wire portion 4 are connected in series to the outer peripheral surface of the winding core 2 and the display storage case 13, which is directly connected to the winding core 2 so as to extend in the axial direction. A fuse element 5 with an arc-extinguishing tube 20 placed around the outer periphery of the section 3 is spirally wound, and the winding core 2 and fuse element 5 are hermetically housed in an insulating tube 1, and both ends of the housed element 5 are connected to the insulating tube 1. In the full-area type high-voltage current-limiting fuse, which is connected to both upper and lower electrodes 7 and 8 fixed on the upper and lower sides of the fuse element 5, and further has an arc extinguishing agent 6 filled in the insulating space 1b of the insulating cylinder 1, the above-mentioned fuse element 5
The conductive plate 17 interposed between and the lower electrode 8 to connect them is connected from the lower end 1c of the insulating cylinder 1 to the lower end outer surface 1d.
A bag-shaped lower cover 16 is attached to the outer circumferential surface 1d of the lower end of the insulating cylinder 1 so as to cover the conductive plate 17, and a small hole 16c for display is provided in the center of the rear end 16a of the cover 16. In contrast, there is a full-area type high-voltage cut-out characterized in that the display body 14, which is housed inside the storage case 13 and is always urged in the pop-out direction, is inserted to such an extent that its tip 14b is not exposed to the outside of the cover 16. Limited current fuse.