Tungsten filament fusing current control method

Abstract

The invention relates to a tungsten filament fusing current control method. A curve relation graph of tungsten filament electrode usable times n and an intermediate variable D / H, a curve relation graph of tungsten filament electrode sensitivity S and the intermediate variable D / H, and a curve relation graph of tungsten filament fusing current I, the height H of a small hemisphere at the end of a prepared tungsten filament and the diameter D of the tungsten filament are obtained through tests; a tungsten filament diameter D and an initial current I are given to obtain an intermediate variable D / H; S and n are obtained subsequently; [nmin, nmax] and [Smin, Smax] can be obtained by changing the initial current I value; and the optimal value of S and the optimal value of n are found out, and finally the optimal fusing current is obtained. The optimal current value of direct current fusing can be determined through the given diameter D of the tungsten filament, fusing is conducted under thecurrent, the tungsten filament electrode has optimized sensitivity and a certain service life, the defect of alternating current fusing is overcome, the detection sensitivity is improved, and the service life of the tungsten filament is guaranteed.

Description

technical field [0001] The invention relates to a control method for tungsten wire fusing current. It belongs to the field of electric power technology. Background technique [0002] There are two methods for preparing the tungsten wire electrode of the spark test device used to detect the intrinsically safe performance of the circuit. The first method is to cut directly with functional scissors, and the second method is to use a tungsten wire fuse device for fusing. The former method is simple, but the end of the tungsten wire is easy to fork, so it is only suitable for the case where the diameter of the tungsten wire is less than or equal to 0.2mm. The end of the tungsten wire prepared by the latter is not easy to fork, and can be applied to various diameters, because the end of the tungsten wire after fusing is in the shape of a small hemisphere as a whole. The structure and parameters of the tungsten wire fuse device specified in Figure B.8 in Appendix B of GB3836.4-2...

AI Technical Summary

Problems solved by technology

[0004] 1. The current of the fusing tungsten wire is an alternating current, and there is a zero-crossing phenomenon, and the tungsten wire generally completes the fusing within a few milliseconds, so that the starting time of each fusing is different, and the fusing time is also different, so the shape of the end of the tungsten wire electrode is different. The number of times (life) used by the tungsten wire is different, which affects the detection sensitivity and consistency of the detection device as a whole

[0005] 2. The fusing device has the best fusing effect for the tungsten wire diameter of 0.2mm, and the preparation effect of other diameters of tungsten wire will be affected, which not only reduces the number of uses but also affects the detection sensitivity

[0006] Therefore, the core of the above problem is the control problem of fusing current

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