熔断器的合理选用

高压限流熔断器通常被人们认为是一种结构简单，保护可靠，投资较省的一种保护电器。实质上，这种熔断器虽然结构简单，但必须以严格的工艺和质量控制规范保证方能生产出可靠的高性能产品,同时还要正确的使用否则有可能导致它的保护功能丧失。以下简要介绍该产品的选用导则，欲了解详情请与本公司联系.
The high-Volt limit-current fuse generally is known as one protection electrical device with characteristics of simple structure,reliable protection and economical investment，however，actually though this type fuse has simple structure，this product with super performance only can be manufactured by means of strict technology and quality control norm, additionally,it is only
correctly using-it that can make full use of its normal protection function. this product’s use regulation would be introduced briefly below, anyone needing to have more information about it please contacts us．

对于熔断器来讲，使用时的安装环境条件很重要，它不但影响熔断器·性能，而且影响其可靠分断故障能力。因此根据使用条件要
加以正确的考虑.常见的一种安装方式是把熔断器安装在一个三相封闭的箱体中，这时熔断器须降容1 5％使用。额定电流小于20A的熔断器可不
考虑降容，因为小额定电流熔断器发热少，温度低，封闭环境对其影响不大。还有一种安装方式是把熔断器单支封闭在一个绝缘树脂浇注的筒内，在这种情况下，熔断器须容2 5％使用才能保证不使熔断器过热而损坏。额定电流2 0 A以下的熔断器仍可不考虑降容。按照有关标准规定，熔断器正常工作的环境温度在-2 5℃—+4 0℃之间，当温度低于-2 5℃时熔断器的机械性能将受到影响，而当温度高于+4 0℃时每升高1℃熔断器应降容1％使用。
对并联熔断器截流特性和I2t特性可遵循下式原则
lp总=n x(单—熔断器预期电流lp／n时的l p1)
式中lp总—并联后的截流峰值；
n—熔断器并联数：
lp—预期电流有效值；
Ip1—单—熔断器截流峰值
I2t总=n x(单—熔断器预期电流lP／n时的I2t值)
需要注意是决不能把熔断器简单的串联使用在高一级的电压电路中

The instalIment surrounding condition in use is very important for the fuse in that it not only affects the fuse’s perfo rmance,but also takes infuence on the reIiabIe abiIity of b reaking obstacle,therefore,operator should take the use condition into account．One common instalIment way is instalIing the fuse into case body with three-phase being sealed,at this time,thefuse should be decreased by 15 percent in capacity before used except the fuse with rated current being lower than 20A,because the fuse with smalI rated-current has Iittle heat radiated in addition to Iow-temperature,so the sealed surrounding does Iittle influence onto it．Another instalIment way is sealing one set of fuse into one tube poured with insuIation resin,under this circumstance, the fuse should be decreased by 25％in capacity before used in order to prevent the fuse from being damaged because of over-heated except for the fuse with rated current being Iower than 20 A According to relevant standard regulation,the normol work the fuse temperature of fuse ranges from-250℃ to 400℃,The fuse’s mechanical performabce would be affected positively provided the temperature is Iower than-25℃,vice versa,the fuse should be reduced by 1％in capacity per 1 Rise in temperature when the temperature is upper than 40℃before used.

As for the fuse installed in the cupboard with th ree-phase being not sealed,for the mutual interruption between temperature-
rising of th ree-phasefuse,the fuse could be decreased by 1 0％in capacity before used except for fuse with rated current being
lower than 20A．Generally, as for the fuse with rated current being lower than 10A，operator should do his best to make the fuse
away from landing metal support because of fuse-body’s easily-aging resulted from long-term co rona discharging . For
strengthening the current grade of fuse sometime，user would use two or three untis of fuse device for paralleling use,at this
time,the mutual influence between fuse’t emperature should be taken into account by operator,and the fuse should be decreased
by 10-20％in capacity for use generally.
The stem-current and 1²t properties of paralleling fuses can conform to following principle Ip-total：n x(the lp1 of single-fuse’
anticipated current beingl_p/n)
In the equation：Ip-total the stem-current climax value after paralleling n the fuse\s parallel quantity
1_p valid value of anticipated current
1_p1 stem-current climax value of single-fuse
l²t total：n x(the l²t value of single-fuse,anticipated current beingl_p/n)
Noted：the fuse’simple series-connection is banned from being used in the one-grade higher volt circuit