JPS5849564Y2 - Slit type current limiting fuse - Google Patents

Description

[Detailed explanation of the device] This device expands the arc cross-sectional area by confining the arc that occurs when a short-circuit current or overcurrent flows through a fusible piece and blowing it out, within a slit formed in a solid insulator. This invention relates to a slit-type current-limiting fuse that suppresses the flow and exhibits high current-limiting performance.

A conventional current-limiting fuse has a fusible piece inserted into an arc-extinguishing material such as silica sand, and when the fusible piece fuses due to an overcurrent, the arc is extinguished by diffusion cooling within the arc-extinguishing material, thereby cutting off the current.

However, since arc-extinguishing materials such as silica sand are porous, there are many voids, and the arc that occurs during current limiting diffuses within these voids and expands the cross-sectional area, suppressing the increase in arc resistance and making it an excellent limiting material. Flow characteristics cannot be obtained.

For this reason, as a prior art, a structure was developed in which a slit is formed in a solid insulator and a fusible piece is inserted into this slit to conduct electricity, and the arc generated when the fusible piece is fused is cooled by the insulator. The arc is cooled by the solid insulator that forms the slit, and when the solid insulator comes into contact with the arc, the arc cross-sectional area is prevented from expanding. The arc current is limited by the movement of electrons in the arc being hindered by the evaporated vapor generated, making it possible to obtain excellent current limiting characteristics.

This invention was made for the purpose of further improving the current limiting characteristics of the prior art developed above.

Hereinafter, the structure of one embodiment of the slit type current limiting fuse in this invention will be explained based on FIGS. 1 and 2.

In the figure, reference numeral 1 denotes a plurality of laminated fusible pieces, the ends of which are closely held by conductive spacers 2.

3 is inserted between each laminated fusible piece 1 with a cooling plate 4 made of a good heat conductive material such as aluminum, for example, an IJ.
It is a plate-shaped insulator made of a porcelain material such as IJA or alumina, and a space 12 is formed between it and the spacer 2.
5 is a gap formed between each plate-shaped insulator 3; 6 and 7 are a pair of terminals to which the ends of each fusible piece 1 are respectively connected; 8
Reference numeral 9 denotes an insulating plate that holds the fusible pieces 1, plate-shaped insulators 3, and cooling plate 4 stacked alternately from above and below, and is tightened from above and below by bolts 10 and nuts 11 to form the fuse body 20.
is configured.

In one embodiment of the slit-type current-limiting fuse of this invention constructed as described above, current flows from one terminal 6, passes through the spacer 2, the fusible piece 1, and the spacer 2 in order, and then passes through the other terminal 7. leaked from.

When this current value exceeds the minimum fusing current of the fusible piece 1, the fusible piece 1 melts and an arc is generated in the gap 5 formed between the plate-shaped insulators 3, but the heat generated by this arc is transferred to the plate-shaped insulator. The arc is discharged to the outside from the cooling plate 4 through the material 3 and is cooled, and the arc is confined within the slit 5 to prevent the cross-sectional area of the arc from expanding, so that the arc current is significantly limited.

In this way, the current limiting performance is significantly improved, so even if the length of the fusible piece 1 is shortened, sufficient current limiting performance can be obtained. A gap-type current-limiting fuse is obtained.

In addition, since the arc energy is significantly reduced due to the excellent current limiting performance, the generation of molten products is limited to the very surface of the plate-shaped insulator 3, and there is no need to make the plate-shaped insulator 3 large in advance. Therefore, the fuse body 20 can also be made very compact.

Note that by configuring the fuse body 20 in the above embodiment to be placed inside an insulating container (not shown),
Needless to say, it serves to prevent the fusible piece 1 from coming into contact with the external atmosphere, and also to prevent light, sound, gas, etc. generated during current limiting from leaking to the outside.

Furthermore, although porcelain was used as the material for the plate-shaped insulator 3, an inexpensive resin may be used in consideration of cost for applications requiring a small current carrying capacity.

In summary, the slit-type current-limiting fuse in this invention improves current-limiting performance by forming slits between laminated plate-shaped insulators and alternately stacking cooling plates and fusible pieces in these slits. The practical effect is that we were able to provide a small, high-performance product by increasing the current carrying capacity.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the configuration of an embodiment of the slit type current limiting fuse in this invention, and Figure 2 is a line drawn along the line
FIG. In the figure, 1 is a fusible piece, 2 is a spacer, 3 is a plate-shaped insulator, 4 is a cooling plate, 5 is a slit, 6 and 7 are a pair of terminals, 12
is space. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] three or more plate-shaped insulators laminated with gaps in between; fusible pieces and cooling plates alternately inserted into the gaps; both ends of the fusible pieces being held outside the gaps; A spacer electrically connected to the fusible piece and a pair of terminals electrically connected to these spacers, and both ends of the cooling plate are spaced apart from the spacer by a desired distance within the narrow gap. A slit-type current-limiting fuse in which an end of the cooling plate that faces the spacer and that does not face the spacer protrudes outside the slit.