SU744773A1 - Fuse fusible element - Google Patents

Description

(54) FUSE FUSE ELEMENT

one

The invention relates to electrical engineering, in particular to fuse elements.

Known fusible elements of sheet material, which have wide and narrowed parts formed by the cutouts of the material of the fusible element 1. Fusible elements of a similar design are widely known in electrical engineering.

The presence of constricted parts with increased current density and their large ohmic resistance accelerates the operation of the pre-saver at emergency currents, and the presence of wide parts with a small current density and low resistivity ensures the necessary thermal protection of the fuse during a long flow of operating current through it. 15

A disadvantage of the known constructions is that the wide and constricted parts are located in the same plane so that the faces of the cuts forming them are opposed to each other. After melting of the constricted parts at emergency currents, the plasma flows emerging from these faces join and contribute to the propagation of the electric arc across the entire width

a fusible element and the involvement in the melting process of a large amount of the fusible element metal. This leads to the fact that when the circuit is disconnected, the arc resistance grows slowly, its quenching process is delayed and, consequently, the thermal energy passed by the fuse to the protected circuit, determined by the Joule current integral during the emergency current (trip circuit), increases significantly. Reducing the cut-off integral by mutual removal of the edges of the cuts in the fusible element for the required distance leads to the elongation of the tapered parts, the increase in their resistance, and the reduction of the permissible current load on the fuse.

In addition, the adjacent narrowed parts of the fusible elements are in the same plane, having common axes around which a fusible element can occur during its manufacture and assembly. At the small sizes of the narrowed parts it can lead to their destruction.

Claims (2)

The closest to the invention is a fusible fuse element, made of sheet material, curved in length and having wide and tapered portions 2. However, in the said fuse element, tapered and wide portions are located in common planes. The purpose of the invention is to increase the mechanical stability and improve the protective characteristics. In order to achieve the goal, the wide sections adjacent along the length of the fusible element are bent to opposite sides in the form of arches so that edges are formed that extend the narrowed sections, with the arches resting on said edges of wide sections. With this design of the fusible element, the plasma flows emanating from the edges of the notches of the adjacent wide parts do not interconnect, and the narrowed parts do not have common axes, along which they could be bent. FIG. 1 shows the proposed fusible element; in fig. 2 shows section A-A in FIG. one; in fig. 3 and 4 - fusible element options. The wide sections 1 adjacent along the length of the fusible element are bent in the form of arches, resting, with their bases, on the areas adjacent to the narrowed sections 2, in opposite directions so that the plasma flows 3 (shown by arrows) all over them To bend the 1st parts do not connect with each other. At the same time, in the process of burning an electric arc that occurs in narrowed areas, only small volumes of metal of the bent parts that are in close proximity (shown in dashed lines in Fig. 2) to each other participate. To increase the mechanical durability of the fusible element to bending in the areas of weakened cross section, the neighboring parts of the fusible elements adjacent in the width can be located in the planes of the parts bent in one direction (Fig. 3). The advantages of the proposed construction follow from the following. The electric arc after the melting of the isthmuses, the transition to the loose parts, will capture only a small part of them and will mainly pass through parts that are a continuation of the isthmuses. As a result, the arc resistance increases quite quickly, which leads to a rapid decrease in the current and the integral of the current, i.e., to an improvement in the protective characteristics of the arc. Since the mutual distance between the edges of the cuts initiating the plasma flows, with this design is determined not by the length of the narrowed parts, but by the width of the bent parts, the narrowed parts can be made of a sufficiently small length and, consequently, other things being equal, this increases the load current fuse If necessary, in order to improve the protective characteristics with the same current load of the fuse, the width (and hence the section) of the tapered part can be reduced simultaneously with the length reduction, which also contributes to the reduction of the current integral. The arched structure of the bent parts in combination with the arrangement of the narrowed parts in planes in common with the bent parts gives the fusible element the necessary mechanical resistance sufficient to preserve the integrity of the narrowed parts during manufacture. Claims of the invention Fuse element of the fuse made of sheet material, curved in length and having wide and narrowed portions, characterized in that, in order to increase mechanical stability and improve protective characteristics, the wide portions adjacent to the length of the fusible element are bent to opposite sides of each other. in the form of arches in such a way that edges are formed, which are a continuation of constricted areas, and the arches rest on said edges of wide sections. Sources of information taken into account in the examination 1. Kuznetsov R. SG. Apparatuses for the distribution of electrical energy for a voltage of up to 1000 VM, Energii, 1970, p. 394. 2. Fuses series PP57, TU 522. 107-74. / / 7 (Reg. 2 FIG 3 FIG. If