保护用fuse选型说明
FUSE选型指导
6.5x6(金属/玻璃外壳) 8.5x8(圆形塑料外壳) 8X6x4(方形塑料外壳) 0.5~10A/63~250V
• 径向引线的电阻式:
2x7(环氧包封)快/慢断 3x10(塑料外壳)快/慢断 0.5~10A/63V~250V
小型熔断器的基本知识
• 其他：车用熔断器 (Automotive)
• 车用熔断器也是从管状演变和发展而 来的,至今上有部分摩托车/电动车等 还用玻璃管的; • 当今大部分安装在汽车电器盒内的熔 断器大都是片式或条式的,一般每车用 量在30-50个(片式35条式15); • 汽车熔断器都是应用在大电流(片式 0.5~50A/条式40~300A)和低电压(片式 32V/条式80~125V)的条件下的
---MCB Series Beads（General Use/High Speed/High Frequency） ---MBA Multilayer Ferrite Chip Bead Arrays ---MCP Multilayer Ferrite Power Beads(High Current) ---MCB Series Beads（General Use/High Speed/High Frequency） ---MCI/MHI Multilayer Ferrite/Ceramic Inductors
Termination and Solder Ceramic
Fuse Elements
AEM熔断器生产示意图
Materials
Slurry Preparation 浆料准备
Buildup 成型
保险丝的参数选择及其应用
保险丝的参数选择及其应用保险丝的参数选择及其应用在很多电子设备中，都离不开保险丝(Fuse)。
自从十九世纪九十年代爱迪生发明了把细导线封闭在台灯座里的第一个插塞式保险丝之后，保险丝的种类越来越多，应用越来越广。
本文给大家介绍保险丝的参数、选择及应用，希望大家能有所收益。
保险丝的各项额定值及其性能指标是根据实验室条件及验收规范测定的。
国际上有多家权威的测试和鉴定机构，如美国的保险商实验室公司的UL认证，加拿大标准协会的CSA认证、日本国际与贸易工业部的MTTI认证和国际电气技术委员会的IEC认证。
保险丝的选择涉及下列诸多因素：1 正常的工作电流。
2 施加在保险丝上的外加电压。
3 要求保险丝断开的不正常电流。
4 允许不正常电流存在的最短和最长时间。
5 保险丝的环境温度。
6 脉冲、冲击电流、浪涌电流、启动电流和电路瞬变值。
7 是否有超出保险丝规范的特殊要求。
8 安装结构的尺寸限制。
9 要求的机构认证。
10 保险丝座件：保险丝夹、安装盒、面板安装等。
下面把保险丝选用中常见的参数和术语作一些说明。
1.正常工作电流在25℃条件下运行，保险丝的电流额定值通常要减少25％以避免有害熔断。
大多数传统的保险丝其采用的材料具有较低的熔化温度。
因此，该种保险丝对环境温度的变化比较敏感。
例如一个电流额定值为10A的保险丝通常不推荐在25℃环境温度下在大于7.5A的电流下运行。
.电压额定值保险丝的电压额定值必须等于或大于有效的电路电压。
一般标准电压额定值系列为32V、125V、250V、600V。
3.电阻保险丝的电阻在整个电路中并不重要。
由于安培数小于1的保险丝电阻只有几个欧姆，所以在低压电路中采用保险丝时应考虑这个问题。
大部分的保险丝是用温度系数为正的材料制造的，因此，就有冷电阻和热电阻之分。
4.环境温度保险丝的电流承载能力，其实验是在25℃环境温度条件下进行的，这种实验受环境温度变化的影响。
环境温度越高，保险丝的工作温度就越高，其寿命也就越短。
保险丝(FUSE)选型分析
关于FUSE的选择一、介绍每个产品都有保护电路，大部分的电流保护基本都是用FUSE来进行保护，而FUSE的选择关系到产品的正常运行，如果没有选择合适的FUSE将会导致对电路起不到保护作用或总是熔断FUSE。
由于在不同的实际电路中存在各种其他因素，所以选择FUSE需通过具体测试验证来选型。
二、选型需要参数选择一个FUSE需要知道以下参数：1、最大稳态工作电流；2、最大工作温度；3、最大瞬态脉冲电流的波形（峰值、脉冲宽度）；4、应用中可能出现的最大故障电流；5、过载电流和在该电流下的熔断时间；6、所需耐受脉冲电流的次数；7、最大工作电压；8、封装尺寸；9、安规认证标准。
三、参数定义1、工作温度与温度折减保险管都有一个温度范围，但保险管数据手册上宣称的熔断特性等电气特性都是在25°环境下测试的，如果保险丝不是工作在25°，那么选型时，需根据厂家给出的温度折减曲线来进行对保险丝的温度折减，例如此图是每上升25°，保险丝就折减5%。
2、工作电压（Operating Voltage）与额定电压（Rated Voltage）保险丝的最大工作电压应该在额定电压之内，不能超过额定电压。
保险丝的额定电压是与保险丝的分断能力相关的安全指标。
在这个电压下，保险丝可以安全的截断不大于标称分断能力的电流。
3、分断能力分断能力是指在额定电压下保险丝可以安全截断的最大电流。
保险丝的分断电流是一个安全参数，它必须达到或者大于最大故障电流，这样保险丝才会安全熔断，不会产生燃烧、飞弧、爆炸等不安全现象。
4、工作电流（Operating Current）与额定工作电流(Rated current)工作电流是指电路在稳定工作状态下的最大工作电流；额定电流是规格书中宣称的电流。
保险丝在额定工作电流下工作必须大于4小时才能断开（25°环境条件下）。
为保证保险丝长期稳定工作，工作电流需小于保险丝额定电流的75%。
Fuse设计选型详解
Fuse 设计选型详解本文仅针对Fuse（熔断器）选型，PPTC&CPTC及其他过流保护装置或电路不在其列。
一、F use 简介及分类1、Fuse 的结构：（1）熔体：保险丝的核心部分，熔断时起到切断电流的作用。
以管式保险为例，就是玻璃管中间看到的金属丝；（2）电极：熔体与电路联接的部分，该部分必须具有良好的导电性，电阻值极小；（3）支架：固定熔体与电极成为刚性的整体的部分，便于安装使用，熔体相对脆弱，所以要求支架具有良好的机械强度、绝缘性、耐热性、和阻燃性。
以管式保险丝为例，就是玻璃管部分，可以防止内部的熔体被氧化或受外力而断裂，同时也保证在熔体熔断时、熔断后不会产生二次损害；（4）灭弧装置：该部分主要存在于高分断能力或高低压熔断器，可忽略。
2、Fuse 的分类：（1）按保护形式：过电流保护与过热保护，在这里只讨论过电流保护的Fuse；（2）按使用范围：电力保险丝、机床保险丝、电气仪表保险丝（电子保险丝）、汽车保险丝，在这里我们适用于电子保险丝；（3）按形状（安装方式）：管式保险丝（又分平头、尖头、内焊式、外焊式），铡刀式保险丝、螺旋式保险丝、片式保险丝（常见于汽车保险，少数机动车采用管式保险丝）、平板式保险丝、贴片式保险丝；（4）按额定电压：高压保险丝、低压保险丝、安全电压保险丝；科普知识：安全电压的范围，我国规定工频安全电压（有效值）的上限为50V，直流安全电压的上限为120V，我们常说的安全电压36V一般是指工频电压等级，也就是交流电，国家标准GB/T 3805-2008[ 特低电压（ELV）限值] 中规定交流（15Hz～100Hz）的电压的有效值额定值等级有42V，36V，24V，12V，6V，而对于更高频率或直流电的电压限值因为尚无可靠的研究数据，所以标准中未给出相应的限制。
（5）按分断能力：高分断能力保险丝、低分断能力保险丝；（6）按体积：大型、中型、小型、微型；（7）按熔断速度：特慢速保险丝（一般用TT表示）、慢速保险丝（一般用T 表示）、中速保险丝（一般用M 表示）、快速保险丝（一般用F 表示）、特快速保险丝（一般用FF 表示）。
保险丝的选择
Fuse selection guide一、Fuse 选择的几大要素：1.额定电流（rating current*）2.熔断特性（breaking capacity*）3.环境温度（ambient temperature*）4.额定电压（rating voltage）5.分断能力（interrupt capacity）6.安全认证（safety approve）二、real application1.额定电流是指fuse正常工作时的最大电流，正确选用fuse应当考虑其所使用的环境（环境因素有环境温度、环境湿度）、通过的最大电流（包括开关机时的pluse、正常工作时的最大电流等）和老化的影响（熔化热能值melting energy I2t）等因素。
2.熔断特性主要为是熔化热能值（I2t）。
Example:使用地方：LCD TV回路条件：a. 突波( Inrush current ) 波形: 如下图b保证突破通过回数：10 万回c 稳定(Normal current) 电流: 1.42A MAX.d. 假设Fuse周围环境温度Max 50 ℃e. 要求选用fuse为SMD 1206 Type额定负载（rating current）考虑fuse：I=I(normal)/(0.75*0.97)=1.95A其中0.75为选择欧规时的寿命折损系数，0.97为环境温度为50°C的温度折损系数。
熔化热能值（I2t）考虑fuse：从波形看可以采用公式C or E，取其大者。
I2t=0.5*（1.84A）2*0.0122S/(0.22*0.97*0.75)=0.129A2S其中0.5*（1.84A）2*0.0122S为波形匹配下图中的C or E进行的计算后中的较大者，0.22为寿命折损系数，0.95为温度折损系数，0.75为UL折损系数，与fuse spec进行比较知道fuse选用合理。
如果突波为多次上升波形则需分别分开进行计算最后求和。
熔断器的结构、特性及选用介绍
熔断器的结构、特性及选用介绍摘要熔断器也被称为保险丝，IEC127标准将它定义为"熔断体（fuse-link)"。
它是一种安装在电路中，保证电路安全运行的电器元件。
熔断器其实就是一种短路保护器，广泛用于配电系统和控制系统，主要进行短路保护或严重过载保护。
熔断器-正文熔断器利用金属导体作为熔体串联于电路中，当过载或短路电流通过熔体时，因其自身发热而熔断，从而分断电路的一种电器。
熔断器结构简单，使用方便，广泛用于电力系统、各种电工设备和家用电器中作为保护器件。
结构和特性熔断器主要由熔体、外壳和支座3部分组成，其中熔体是控制熔断特性的关键元件。
熔体的材料、尺寸和形状决定了熔断特性。
熔体材料分为低熔点和高熔点两类。
低熔点材料如铅和铅合金，其熔点低容易熔断，由于其电阻率较大，故制成熔体的截面尺寸较大，熔断时产生的金属蒸气较多，只适用于低分断能力的熔断器。
高熔点材料如铜、银，其熔点高，不容易熔断，但由于其电阻率较低，可制成比低熔点熔体较小的截面尺寸，熔断时产生的金属蒸气少，适用于高分断能力的熔断器。
熔体的形状分为丝状和带状两种。
改变变截面的形状可显著改变熔断器的熔断特性。
熔断器具有反时延特性，即过载电流小时，熔断时间长；过载电流大时，熔断时间短。
所以，在一定过载电流范围内，当电流恢复正常时，熔断器不会熔断，可继续使用。
熔断器有各种不同的熔断特性曲线（见图），可以适用于不同类型保护对象的需要。
熔断器分类熔断器根据使用电压可分为高压熔断器和低压熔断器。
根据保护对象可分为保护变压器用和一般电气设备用的熔断器、保护电压互感器的熔断器、保护电力电容器的熔断器、保护半导体元件的熔断器、保护电动机的熔断器和保护家用电器的熔断器等。
根据结构可分为敞开式、半封闭式、管式和喷射式熔断器。
敞开式熔断器结构简单，熔体完全暴露于空气中，由瓷柱作支撑，没有支座，适于低压户外使用。
分断电流时在大气中产生较大的声光。
半封闭式熔断器的熔体装在瓷架上，插入两端带有金属插座的瓷盒中，适于低压户内使用。
FUSE 保险丝
当然，劣质保险丝的分断能力达不到标准规定的要求，使用时同样会发生危害。
当电流流过导体时，因导体存在一定的电阻，所以导体将会发热。且发热量遵循着这个公式：Q=0.24I2RT；其中Q是发热量，0.24是一个常数，I是流过导体的电流，R是导体的电阻，T是电流流过导体的时间；依此公式我们不难看出保险丝的简单的工作原理了。
1.正常工作电流在25℃条件下运行，保险丝的电流额定值通常要减少25%以避免有害熔断。大多数传统的保险丝其采用的材料具有较低的熔化温度。因此，该种保险丝对环境温度的变化比较敏感。例如一个电流额定值为10A的保险丝通常不推荐在25℃环境温度下在大于7?5A的电流下运行。
2．电压额定值保险丝的电压额定值必须等于或大于有效的电路电压。一般标准电压额定值系列为32V、125V、250V、600V。
3．电阻保险丝的电阻在整个电路中并不重要。由于安培数小于1的保险丝电阻只有几个欧姆，所以在低压电路中采用保险丝时应考虑这个问题。大部分的保险丝是用温度系数为正的材料制造的，因此，就有冷电阻和热电阻之分。 4．环境温度保险丝的电流承载能力，其实验是在25℃环境温度条件下进行的，这种实验受环境温度变化的影响。环境温度越高，保险丝的工作温度就越高，其寿命也就越短。相反，在较低的温度下运行会延长保险丝的寿命。
的导电性，不应产生明显的安装接触电阻；三是支架部分，保险丝的熔体一般都纤细柔软的，支架的作用就是将熔体固定并使三个部分成为刚性的整体便于安装、使用，它必须有良好的机械强度、绝缘性、耐热性和阻燃性，在使用中不应产生断裂、变形、燃烧及短路等现象
灭弧装置
电力电路及大功率设备所使用的保险丝，不仅有一般保险丝的三个部分，而且还有灭弧装置，因为这类保险丝所保护的电路不仅工作电流较大，而且当熔体发生熔断时其两端的电压也很高，往往会出现熔体已熔化（熔断）甚至已汽化，但是电流并没有切断，其原因就是在熔断的一瞬间在电压及电流的作用下，保险丝的两电极之间发生拉弧现象。这个灭弧装置必须有很强的绝缘性与很好的导热性，且呈负电性。石英砂就是常用的灭弧材料。
Fuse 型号说明 ,参数说明
着电子元器件的小型化和贴片化，保险丝也随之走向小型贴片化，贴片式保险丝的应用愈来愈广，它们在电脑及外设接口、平板电视、手机、汽车电子电路及电池组等的过流保护中已大显身手。
除常见的熔断型保险丝外，近些年来，PPTC自复式保险丝（聚合物正温度系数热敏电阻）的兴起，更为IT设备的保护带来了新局面。
与贴片二、三极管和贴片IC等元件一样，贴片保险丝目前还没有统一标定方法，所以各生产厂家采用的代码各异。
有时甚至还出现同厂家用同一种代码（在不同系列中）代表不同额定电流的现象。
更有一些怪怪的代码，连识别都感到困难，给维修代换平白增添了不少麻烦。
本文列举了各类常用贴片保险丝的识别方法，以期满足维修代换的需要。
更希望读者逐渐积累识别贴片式保险的方法，在实践中不断提高自己这方面的能力。
一、常用熔断型贴片保险丝的识别熔断型贴片保险丝（贴片熔断器）与通常使用的保险丝功能基本相同，它在额定的电流下（电路正常时）能正常工作，当电路出现故障达到或超过熔断电流值时熔断，这可以避免故障进一步扩大，从而保护了电路。
保险丝（熔断器）按熔断速度分为：特慢速保险丝（一般用TT表示）、慢速保险丝（一般用T表示）、中速保险丝（一般用M表示）、快速保险丝（一艘用F表示）和特快速保险丝（一般用FF表示）等五种类型。
按最大分断电流的大小又可分为低分断型（L）和高分断型（H）两种。
熔断型贴片保险丝的标示方法一般可分为直接标示法和代码标示法两种，而代码标示法又可细分为字母(或数字)标示法与图形标示法两类，1 直接标示法图1的贴片保险，将主要特性参数直接标注在元件正面，称为直接标示法，简称直标法。
直标法一般用于体积略大的“方头”瓷管保险和长方体塑封贴片保险上。
图1中，上面一行的第1个符号为生产厂家力特(LITTELFUSE)公司的厂标，后面的F说明为快速熔断型，500mA是额定电流，字母L表示为低分断型；下面一行为额定电压交流250V，最后那个图形标志表示产品符合IEC（国际电工委员会）普通保险丝的标准。
fuse选型
1保险丝类1.1保险丝结构介绍一般保险丝由三个部分组成：一是熔体部分，它是保险丝的核心，熔断时起到切断电流的作用，同一类、同一规格保险丝的熔体，材质要相同、几何尺寸要相同、电阻值尽可能地小且要一致，最重要的是熔断特性要一致；二是电极部分，通常有两个，它是熔体与电路联接的重要部件，它必须有良好的导电性，不应产生明显的安装接触电阻；三是支架部分，保险丝的熔体一般都纤细柔软的，支架的作用就是将熔体固定并使三个部分成为刚性的整体便于安装、使用，它必须有良好的机械强度、绝缘性、耐热性和阻燃性，在使用中不应产生断裂、变形、燃烧及短路等现象；电力电路及大功率设备所使用的保险丝，不仅有一般保险丝的三个部分，而且还有灭弧装置，因为这类保险丝所保护的电路不仅工作电流较大，而且当熔体发生熔断时其两端的电压也很高，往往会出现熔体已熔化（熔断）甚至已汽化，但是电流并没有切断，其原因就是在熔断的一瞬间在电压及电流的作用下，保险丝的两电极之间发生拉弧现象。
这个灭弧装置必须有很强的绝缘性与很好的导热性，且呈负电性。
石英砂就是常用的灭弧材料。
参数解释：①．NORMAL OPERATING CURRENT: FUSE所串联回路通过的满载电流②．INTERRUPTING RATING:在保险丝额定电压范围内所允许保险丝安全熔断的电流，目前使用的半导体保护保险的INTERRUPTING RATING一般达到20KA，如果此电流持续时间足够短，Fuse将不会熔断，fuse具有重复承受此冲击的能力。
但是注意，如果短路电流超过此分断电流规格，可能导致FUSE无法正常熔断。
③．VOLTAGE RATING:Fuse所承受的额定电压，如果Fuse熔断后两端的电压差越高，由于内部的拉弧效应，Fuse熔断速度越慢，参考曲线如下：图中K表示I2t的能量系数。
④．TIME-CURRENT CURVE: Fuse 过载能力的查核表，通过电流/时间曲线可以找出fuse在不同电流模式下的过载时间，所有fuse均有此曲线，下图为Ferraz 30A Fuse的TIME-CURRENT CURVE曲线供参考。
电子产品保护设备的选型与应用指南说明书
How to apply fuse clipsEmploying fuse clips for cartridge fusesEvery electrical circuit has the potential for a damagingovercurrent or short circuit event. For this reason, many product standards are explicitly created to ensure product safety for themyriad of potential conditions it may be subjected to. The fuse is one of the most common devices to help protect electronic equipment and its users from the risk of electrical fire or shock due to these events, making it one of the most frequently employed solutions to obtain certification for these product and safety standards. When it comes to electronic or printed circuit board (PCB)applications, cartridge fuses are a cost-effective option and typically have higher voltage and interrupting ratings when compared to other types of electronic or PCB fuses. Given these characteristics, they can help ease the fault current investigation required to meet safety standards. For example, a power supply design may include evaluating all possible ways a user may connect to a power source and the possible fault currents each of those sources may deliver. When using cartridge fuses, a designer will need additionalaccessories to integrate this component on a PCB. Axial leads for thru-hole applications are one option (see Figure 1), but for designs requiring fuse replaceability or allowing the end-user to supply the fuses, fuse clips are a popular option. This document isintended to outline selection considerations, user guidelines, and considerations during assembly and fuse installation.Figure 1: Fuses with axial leads can be leveraged for PCBinstallation. However, this prevents the user from easily replacing the fuse cartridge. Consequently, fuse holders are used for easeof fuse installation and replaceability.Technical Note ELX1149Effective February 2022Fuse accessoryapplication guidelinesFuse holder productsThere is no one-size-fits-all fuse holder, and the suitability ofthe particular fuse clip depends heavily upon the end application. To best understand which fuse holder best meets the needs of an end application, see Eaton’s guide on selecting a fuse holder . Eaton offers four different fuse holder products:• Printed Circuit Board (PCB) fuse clips • Printed Circuit Board (PCB) fuse holders • Panel mount fuse holders •In-line fuse holdersThe fuse accessory selection guide offers assistance in selecting the correct fuse holders for a particular diameter fuse cartridge. The constructional differences between these types of fuse holders can be seen in Figure 2.Figure 2: Four different fuse clips can be employed for cartridge fuses, including (a) panel mount fuse holders,(b) PCB fuse clips, (c) PCB fuse holders, and (d) in-line fuse holders.Fuse clip selection considerationsChoosing the right fuse clip for the cartridge fuseEaton offers a wide variety of PCB fuse clips for 5 mm, ¼” (6.3 mm), and 13/32” (10 mm) diameter cartridge fuses, as well as fuse clips for ATC/ATM auto blade fuses (see Figure 3). Much of fuse clip selection is due to preference; users may prefer a particular pin configuration or end stop variety for any number of reasons. Fuse clip pin configurationsEaton fuse clip circuit connections are all thru-hole. However,pin configurations can vary between straight, angled-out, angled-in, or the stand-off construction that keeps the bottom of the clip from hitting the board during the installation/removal process.Figure 4: Fuse clips can come with straight, angled-out, angled-in, or stand-off configurations (left to right).Constructional differences in fuse clipsFuse clips can employ end stops (also referred to as “ears”)to hold the fuse cartridge in place (see Figure 5). The choice between these two is mainly based upon the designer’s preference.Both options provide an adequate fuse contact force while the end stops can help prevent connection issues due to fuses exiting the clips. As shown in Figure 5, these clips are of the same height (0.255“) with the two fuse clip variations. Eaton offers 1/4” (6.3 mm) diameter fuse clips with straight, angled-in, and angled-out leads.Figure 5: Fuse clips can either use end stops (top) or no end stops (bottom).Some variations of ears (or end stops) will also include metal tabs as stoppers for the cartridge fuse.Figure 6: Fuse clip with metal tabs to prevent slippage fromhorizontal motions or vibrations.FamilyMax current ratingFuses acceptedCircuitconnections 3rd party certifications1Axxxx40 A 10 mm Thru-hole cURus 30 A1/4" (6.3 mm)Thru-hole cURus10 A 5 mmThru-hole 15 AATC/ATM auto blade fuses Thru-hole HTC-2xx6.3 A5 mmThru-holeFigure 3: Specifications for fuse clips can be found inEaton’s circuit protection devices & applications catalog.Fuse clipsa bc dHorizontal fuse heightThe horizontal fuse height from the board varies per fuse family (see T able 2). This range in fuse heights from the board ismost apparent in the various fuse clip families made for 5 mm cartridge fuses. The two fuse clips in Figure 7 support the same 5 mm diameter cartridge fuse and have straight leads with standoffs. However, they have different fuse heights of 3.2 mm and 11.2 mm. The choice between fuse heights depends upon the access a user may need to the fuse clips and the profile of the PCB. Employing a shorter fuse clip for high integration, lower-profile PCBs may be more optimal.Figure 7: 1A3399 fuse clip with a 3.2 mm fuse height from the board and the 1A5018 fuse clip with an 11.2 mm fuse height from the board. Both options support 5 mm cartridge fuses. Body materialThe fuse clip’s body material and plating composition may vary as well (see T ables 1 and 2). Fuse clips must exhibit a high degree of strength and a resistance to permanent deformation to withstand the strain of fuse installation and replacement. For this reason, the body of the fuse clip must have a high yield strength and modulus of elasticity to provide adequate contact forces while also preventing any material deformations during handling (see T able 1). Additionally, the body materials contribute to the overall circuit resistance.Thus, selecting a reasonably conductive alloy to carry the operational current is another condition to consider. Generally speaking, more conductive alloys are recommended for higher current applications. For each material, there are heat treating or additionalmanufacturing processes that help properly utilize the material properties of each alloy and ensure suitability for virtually all electronic applications, including the current carry capability. Plating compositionThe plating composition of fuse clips is typically either bright tin or pure silver (see T able 2). The primary purpose of plating layers of fuse clips is to support solderability in the application. While both are good options for solderability, given the alloy markets, tin plating is a more economical option. Since there are differences in conductivity between these two plating alloys, silver plating does offer slightly improved conductivity for the overall clip. However, the thickness of plating doesn’t provide significant improvements in current carrying capability. Each application and operational conditions are different though. Lastly, if there are concerns around tin whiskers of bright tin plating, silver plating does provide an option to avoid costly and time consuming testing to help speed to market.Properly installing a fuse clip Fuse clip assemblyT wo fuse clips must be horizontally aligned and orthogonal tothe fuse cylinder to properly install fuse clips. Naturally, the centers of the fuse clips should be centered with the contacts of the fuse cylinder (Figure 8). This need for proper orientation and alignment of the fuse clips necessitates the use of fuse clips with identical fuse heights from the PCB. In this case, one fuse clip might contain end stops while the other might not for the ability to slide the fuse in and out. T o mitigate the risk of an unusable fuse clip installation,employ two identical fuse clips. While the fuse clips have an inherent resistance to deformation, it is essential not to deform them due to improper installation, which includes not pressing the fuse past where it is intended to be held by the clip. This requires careful insertion/removal of any fuse cartridge. The through-hole fuse clips must be soldered straight to ensure proper heat rise. This way, the fuse clips and fuse assembly can carry current safely without issues.Figure 8: Fuse clips must be in plane with each other and orthogonal to the fuse cylinder. It is crucial to get the orientation and alignment correct to install a fuse.Per the UL4248, the UL standard for fuse holders, a dummy fuse is for testing and has a 30°C limit in order to have a consistent and standardized resistance. However, many fuses in the relevant fuse diameters have varying current handling capabilities and DC resistances (DCRs) than a dummy fuse. The DCR of the fuses will inevitably be higher than that of a dummy fuse, which will contribute significantly to a different heat rise vs the standard laboratory testing. For this reason, the standard approaches may not be sufficient for ensuring sufficient heat rise. Additional testing should be carried out under worst-case (or similar) conditions that the equipment may experience to ensure the suitability of the installation in harsh electrical and environmental conditions. This testing could include testing the board within higher ambient temperatures, higher currents, with the potential use of higherresistance fuses by end-users.Eaton is a registered trademark.All other trademarks are property of their respective owners.EatonElectronics Division 1000 Eaton Boulevard Cleveland, OH 44122United States/electronics© 2022 EatonAll Rights Reserved Printed in USAPublication No. ELX1149 BU-ELX22008February 2022Other worst-case scenarios may consist of the experimental use of thinner PCB traces or wires with no ambient airflow. Larger PCB trace weight can help thermally conduct and dissipate additional heat. Natural or forced convective cooling would also reduce heat rise; however, suitability is up to the end application. Eaton andauthorized distributors provide the expertise and required samples toassist engineers in designing and installing fuses.T able 3: PCB layout from the 1Axxxx datasheet.Follow us on social media to get thelatest product and support information.。
《FUSE保险丝》课件
2
步骤二
选择适当的保险丝规格和类型。
3
步骤三
正确安装保险丝并连接电路。
FUSE保险丝的维修与更换
当保险丝熔断时，我们应该首先排除故障原因，修复电路问题。然后，按照以下步骤更换保险丝：
1. 断开电源。 2. 找到熔断的保险丝。 3. 小心取下熔断的保险丝。 4. 安装新的保险丝。 5. 恢复电源，测试电路。
FUSE保险丝的优点
1 响应迅速
2 简单易用
保险丝在电流异常时能立即熔断，保护设 备安全。
更换保险丝简单方便，不需要复杂的操作。
3 经济实惠
4 广泛应用
保险丝的成本相对较低，是一种经济实用 的电路保护器件。
适用于各种电气设备和电路，应用范围广 泛。
使用FUSE保险丝的方法
1
步骤一
了解电气设备的负载和电流要求。
《FUSE保险丝》PPT课件
欢迎大家来到本次《FUSE保险丝》PPT课件！在这个课件中，我们将介绍保 险丝的作用、种类、优点，以及使用、维修和更换保险丝的方法。让我们一 起来探索吧！
公司介绍
我们是一家专注于电气设备保护的公司，致力于为客户提供高品质的FUSE保险丝解决方案。我们的专 家团队拥有丰富的经验和技术知识。
FUSE保险丝的作用
FUSE保险丝在电路中起着重要的保护作用，当电流异常增大时，保险丝会熔 断，切断电路，从而保护电气设备免受过载和短路的损害。
FUSE保险丝的种类
玻璃管保险丝
适用于一般电路保护，常 见于家庭和办公室电路。
陶瓷保险丝
具有更高的耐高温性能， 适用于工业和高功率设备。
低压保ቤተ መጻሕፍቲ ባይዱ丝
用于低电压电子设备的保 护，如计算机和通信设备。
fuse 保险丝的工作原理
《fuse 保险丝的工作原理》
fuse 保险丝是一种常见的电路保护元件。
保险丝的工作原理是基于电流的热效应。
当电路中的电流超过保险丝的额定电流时，保险丝会发热。
如果电流持续增大，保险丝的温度会不断升高。
当温度达到保险丝的熔点时，保险丝会熔断，从而切断电路，保护电器设备和电路不受损坏。
例如，在一个家庭电路中，如果某个电器发生短路，电流会急剧增大。
如果没有保险丝的保护，过大的电流可能会导致电线过热起火，甚至引发火灾。
但是，由于安装了保险丝，当电流超过保险丝的额定电流时，保险丝会熔断，切断电路，从而避免了危险的发生。
保险丝的额定电流是根据电路的负载情况来选择的。
如果额定电流选择过大，当电路发生故障时，保险丝可能不会及时熔断，起不到保护作用；如果额定电流选择过小，保险丝可能会在正常工作时频繁熔断，影响电器设备的正常使用。
此外，保险丝还有不同的类型，如玻璃管保险丝、陶瓷保险丝、贴片保险丝等。
不同类型的保险丝适用于不同的场合，用户可以根据实际情况选择合适的保险丝。
保保险丝选择指南
Fuse Selection GuideAlthough care is taken to properly design electrical and electronic circuits; overcurrents in the form of short-circuits and overload can occur. The sole purpose of fuses and circuit breakers is to protect personnel and/or equipment from serious harm when an overcurrent condition arises. This guide is intended to help create a better understanding the various parameters of overcurrent protection and the proper application of circuit protective devices. This guide creates a basic understanding of overcurrent principles and applications but is not intended to supplant sound engineering principles or replace specific application testing.OvercurrentsAn overcurrent is a condition which exists in an electrical circuit when the normal load current is exceeded. The two basic forms of an overcurrent are overloads and short circuits. Fuses and circuits breakers primary role in a circuit is to protect personnel and equipment when dangerous overcurrents do happen.Short CircuitA short-circuit is an overcurrent condition where an abnormal, low-resistance, circuitpath is introduced into the circuit. This low-resistance path bypasses the normal load and can create extremely high currents (up to 1000x the normal current under some conditions).Under normal conditions a typical circuit may be described by Ohm’s Law as follows:When a short circuit occurs, a low-resistive, abnormal path is created which will cause the circuit current to increase as the circuit resistance is decreased. The current when a short circuit is introduced can exceed 1000 times the normal current of the circuit. The circuit diagram of a short circuit is shown below:Over LoadAn overload is an overcurrent condition where the current exceeds the normal full load-capacity of the circuit but where no fault condition (short-circuit) is present. A momentary overload condition (also known as “in-rush” currents) may also occur when a circuit is first initialized due to capacitor charging and/or motor-startup. A over load circuit diagram is shown below:In order to select the proper protective device, the following parameters and criteria need to be considered:1.What is the normal operating current of the circuit?2.What is the operating voltage?3.Is the circuit AC or DC?4.What is the operating ambient temperature?5.What is the available short-circuit current?6.What is the maximum allowable I²t?7.Are there in-rush currents available?8.Is the protective device being used for short-circuit protection, over-loadprotection, or both?9.What are the physical size limitations?10. Is the PCB surface mount or thru-hole?11.Does the fuse need to be "field-replaceable"?12.Is resettability an issue?13.What safety agency approvals are needed?14.How will I mount the device?15.What are the cost considerations?What is the normal operating current of the circuit?In order to select the right amperage of the fuse, you first need to know the full-load steady-state current of the circuit at an ambient temperature of 25º C (68º F). Once the current value is determined, then a fuse rating should be selected as to be 135% of this value (taken to the next standard value).For example, if the normal steady-state current is calculated to be 10 amps, then a 15A fuse rating should be selected [10 amps x 135% = 13.5 amps, the next larger standard size is 15A].It is important to note that if the fuse is intended to be used in an environment with possibly very high or low ambient temperatures, then the nominal fuse current would need to be sized significantly higher or lower (see ambient temperature below).What is the operating voltage?The basic rule of thumb is that the voltage rating of the fuse must always higher than the voltage rating of the circuit that it is protecting.For example, if the circuit voltage is 24 volts, then the fuse voltage rating must be higher than 24 volts (yes...it can be 250 V...just so long as it’s higher than the circuit voltage). Is the circuit AC or DC?There exist two distinct types of circuits AC (alternating current) and DC (direct current).AC power is what you will typically find in your home from the electrical utility. AC power is created primarily by moving machines such as generators and delivered through the electric grid.DC power is typically used in electronic and automotive applications. DC power generally is created via a chemical reaction (as batteries and solar cells) or converted AC power through the use of AC to DC power supplies.With AC power, the current and voltage oscillate back and forth. This oscillation helps the fuse to clear quickly. DC power on the other hand doesn’t oscillate so the fuse must find other means to clear itself when opening.Because of these differences, some fuses are designed specifically to be used in DC applications (such as automotive fuses). Some AC rated fuses may be used in DC applications, however there may be a voltage de-rating in these cases.What is the operating ambient temperature?Ambient temperature is a fancy way of saying the “outside air” surrounding the fuse. Normally, the fuses are tested in "laboratory conditions" by the safety agencies such as UL and CSA. The lab conditions are almost always set at 25°C or 77°F. Unfortunately, most real world conditions are not those found in a laboratory.Fuses are heat sensitive devices meaning that it takes heat (via the overcurrent) in order to melt the fuse element inside the fuse. The more heat...the faster it takes to melt the fuse element...the less heat...the longer it takes to melt the fuse element.If a fuse will be subjected to a higher temperature than 25°C, then the fuse amperage will need to be increased as to compensate for the higher temperature (to avoid "nuisance tripping"). Likewise, if the fuse will be used at a lower temperature, then the fuse amperage needs to be lowered (or else it might never open).The rule of thumb is that for every 20°C higher or lower in temperature, the fuse should be re-rated higher or lower 10-15%.An example of a fuse re-rating when higher ambient temperatures are present:Normal full-load current:1 AmpNormal fuse sizing:1.5 Amps (135% of full load current taken to the nexthigher standard rating)Ambient Temperature: 65°CRe-rating:Re-rating: 2 Amps (130% of normal fuse rating) Conversely, when a fuse is intended to be used in extreme low temperature conditions, the fuse must have a lower rating than that in normal conditions.An example of the fuse re-rating when lower ambient temperatures are present:Normal full-load current:1 AmpNormal fuse sizing:1.5 Amps (135% of full load current taken to the nexthigher standard rating)Ambient Temperature: -15°CRe-rating:1.2 Amps (70% of normal fuse rating taken to the nexthigher standard fuse rating)What is the available short-circuit current?The available short circuit current is the measured or calculated current that can be delivered to a circuit by a power source when a short circuit is present. This information is extremely important as an overcurrent protective device has only a finite ability to safely open a circuit when a fault condition occurs. Therefore the amount of fault current available is a critical piece of information in order to select the proper protective device.The available short circuit calculation can be very complex and generally should be left to qualified engineers to calculate. These calculations are generally based on the following factors:•How much short-circuit current is available from the utility?•What is the resistance of the wiring from the utility to the piece of equipment where the fuse is installed?•What is the internal resistance of the piece of equipment where the fuse is installedOnce all of these factors are known, then the engineer can calculate the available short circuit current to the fuse.The fuse must be selected as to have a greater short circuit rating than what is available in the circuit (otherwise the fuse can explode and cause great harm to people and equipment!)What is the maximum allowable I²t?All overcurrent protective devices take a certain amount of "reaction time" when they open to clear a circuit fault. During the time it takes for the fuse to open, there is energy flowing through the fuse. That energy is measured in I²t. There two parts to the fuse’s "reaction time".1) The time it takes to melt the fuse element (also known as the melting time, T m).2) The time it takes to quench the electrical arc (also known as the arcing time, T a).The total time open the fault is known as the total clearing time. T c + T m + T aDuring this clearing time, there is energy is being "let-thru" the fuse. The downstream components are then subjected to this extreme energy as it passes through the fuse (if only for a few milliseconds).In order to specify the proper fuse or circuit breaker in a circuit, the engineer must know the withstand capabilities of the downstream circuit components and select a fuse whose let-thru energy is below that of those components.Are there "in-rush" currents available?Depending on the circuit, there are times when a large amount of current is requiredwhen a piece of equipment is turned on. The types of components that can cause this type of in-rush include motors, fans, and capacitors.The in-rush current can be as high as 6-10 times that of the normal current (for example a typical TV might draw 3A but the in-rush could be as high as 30A). These currents are typically harmless and subside within 1-2 seconds of startup.During an in-rush, the fuse should not open. The specified fuse in this case should be a time-delay fuse allowing the piece of equipment to start up properly without a nuisance opening of the fuse when the overcurrent occurs.Is the protective device being used for short-circuit protection, over-load protection, or both?If the device is to be used as short-circuit protection, the fuse or circuit breaker must interrupt the fault quickly (generally less than 4 milliseconds) in order to give the maximum protection to equipment and personnel.If the fuse or circuit breaker is intended for over-load protection only, then it can be much slower in reacting to the over-current - seconds or even minutes as compared to milliseconds...All fuses offer some form of both short-circuit protection as well as over-load protection whereas many circuit breakers however are over-load protection ONLY and have no capabilities to protect against dangerous short-circuits.What are the physical size limitations?Many times the fuse or circuit breaker needs to be mounted into a place with physical size limitations.It is this reason that fuse and circuit breaker manufacturers have created a wide selection of components with varying physical sizes. Typically however, there are a trade-offs that the engineer must consider.Generally speaking, the smaller the fuse, the less current and/or capabilities that the fuse or circuit breaker may have. For example, a subminiature fuse maybe limited to 15A where as the larger 1/4" x 1 1/4" glass tube fuse can accommodate up to 40A.Additionally, although the fuse can be smaller, the corresponding fuse holder maybe substantially bigger adding to the consideration.Is the PCB surface mount or thru-hole?There are several different options for both surface mount fuses and thru-hole fuses.With surface mounted fuses, there are multiple sizes available from a 6125 (6.1 x 2.5 mm) package all the way down to a 0603 (0.6 x 0.3 mm) package.The thru-hole options are even greater with axial-leaded options available on all of ourstandard glass and ceramic fuses as well as a variety of leaded subminiature and micro fuses.These same options are available in resettable fuses as well.Additionally, the fuse mounting can also play a part in the designers’ decision especially if the fuse needs to be field-replaceable.Does the fuse need to be "field-replaceable"?Fuses are intended to open a circuit when an overcurrent occurs; whether it be a short-circuit or an over-load. A decision by the engineer needs to be made as to whether or not the fuse should be field replaceable.The primary reason for making the fuse replaceable is simply convenience for the end-user in getting their equipment back up and running.The reasons for choosing not to have the fuse field replaceable are two-fold:1.There can be a significantly greater cost to the manufacturer to include afuseholder as opposed to directly soldering the fuse into or onto the PCB2.The manufacturer may not want the end-customer to access the interior of theequipment to replace the fuse for liability issues. This is especially true when ashort-circuit was the cause of the problem in the first place.3.The manufacturer may have some "planned obsolesce" of their parts and maywant to replace the entire circuit board rather than have someone replace just the fuseIs resettability an issue?There are one-time use fuses and resettable type fuses available to the engineer.Both types of fuses provide short-circuit and over-load protection. Resettable fuses are limited to circuit applications below 9 amps (at 12V) and even less current at higher voltages.Circuit breakers can also provide resettability and can range from 1A to 6000A.One-time fuses are just as their name implies. Once they are called upon to act, the interior link melts and the fuse must be replaced. Just because the fuse is replaced, there can still be a short-circuit or over-load still present in the circuit which can cause the newly replaced fuse to open as well. Care should be taken to correct whatever problem that may have occurred when the fuse opened in the first place...before replacing the open fuse with a new fuse.What safety agency approvals are needed?There is an entire alphabet soup of world-wide safety agencies out there. UL, CSA, IEC, CCC, PSE, VDE, Nemko, Semko and TUV are some of the most popularagencies.The agency approvals needed by manufacturers depends solely on what type of equipment they are making and where in the world they hope to sell their equipment.Fuses typically are available with several approvals (for example UL and CSA). Even within a single agency, there can be multiple types of approvals such as UL listing versus UL recognized. .Certain equipment does not require any agency approvals such as many automotive or low-voltage applications.The biggest issues as it relates to safety agency approvals for fuses is that there are several different test methodology and standards depending on the agency involved. This might mean two different fuse characteristics for what is apparently the same fuse and/or application.How will the fuse be mounted?One of the most careful considerations that need to be made is the mounting of the fuse in the circuit. There are several options at hand:1. Direct Solder - In this method, the fuse is directly soldered into or onto the printedcircuit board (PCB). The drawback to this design is the lack of field replaceable parts as discussed in great detail in section 11 but cost can be significantlyreduced with this mounting method.2. Fuse Clips - Fuse clips are relatively inexpensive and allow for fieldreplaceability. Fuseclips are typically mounted on a PCB so any attempt atreplacing the fuse will require opening of the piece of equipment by the end-user. Additionally, removing a fuse from a PCB without disconnecting the power source could lead to an electrical shock when touching the fuse. Fuse clips are available for all "tube" fuses as well as microfuses. Typically fuseclips are limited to 15A of normal current. Fuse clips are generally not listed or recognized by any safety agencies.3.Panel Mounted Fuseholders - Panel mounted fuseholders allow for easy accessfor the end-user to replace the fuse in the field. The panel mount fuseholder isshock-safe meaning that the fuse is removed safely when the cap of thefuseholder is removed preventing the possibility of electrical shocks.Fuseholders are typically tested and approved by safety agencies such as ULand CSA. Fuseholders are typically available up to 30A.4. Fuse Blocks - Fuse blocks are like fuse clips however they do not need to bemounted on the PCB. Fuses mounted in fuse blocks are typically only accessible by opening the piece of equipment which could lead to electrical shocks if theequipment is not disconnected from the power source. Fuse blocks are one ofthe few methods to mount fuses of large amperage.5.Inline Fuse Holders - Inline fuse holders are typically used as a part of a wireharness assembly or where no surface is available to secure another type of fuse mount. Inline fuse holders are generally available up to 100A in lower voltageapplications and up to 30A in higher voltage applications.What are the cost considerations?The costs considerations can vary by several degrees depending on the size, performance, and mounting of the fuse. Generally speaking, the larger a fuse is; the most it will cost (due to higher material costs to build the fuse).The performance characteristics of a particular fuse are also a large cost consideration.A low voltage automotive fuse might a fraction of the cost as compared with a 500V super high-speed, ceramic tube fuse both rated at 10A.Safety agency approvals will also add to the overall cost of the fuse.One of the largest costs of a fuse is the fuse holder. A typical panel-mount fuse holder may cost in upwards of 10 times than that of the fuse itself.。
fuse选用规则
保险丝选用设计规范2008-02-13 10:421.目的为了使本公司产品设计文件中有关保险丝设计选用的技术要求进一步规范化，特制定本规范。
2.适用范围适用于本公司产品设计过程中对保险丝的选用。
3.规范3.1保险丝分类3.1.1本公司保险丝目前有功得和SUN两家供应商，除定型的客户已承认的机种还用功得的保险丝外，由于采购和成本原因新开发的产品所用保险丝一般选用SUN。
3.1.2从熔断速度来讲，保险丝一般分为快速型和慢速型两种，以下以SUN为例说明：3.1.2.1 5G、5GP、5F、5FP、6G、6GP为快速型，其中：a. 5G、5GP、6G和6GP有UL认证；b. 5F和5FP无UL认证；c. 5G、5F和6G无引脚；d. 5GP、5GP和6GP有引脚。
3.1.2.2 5S、5SP、5T、5TP、6S、6SP为慢速型，其中：a. 5S 、5SP、6S和6SP有UL认证；b. 5T和5TP无UL认证；c. 5S、5T和6S无引脚；d. 5SP、5TP和6SP有引脚。
3.1.3保险丝还有温度保险丝和过流保护器两种延伸类型，温度保险丝主要用于变压器里作温度保险用，过流保护器主要用于电源电流大于10A以上的机种作过流保护用。
3.2选型3.2.1 100V-120V保险丝选用5G、5GP、5F、5FP、6G、6GP快速型保险丝，220V-240V保险丝选用5S、5SP、5T、5TP、6S、6SP慢速型保险丝，OEM机种按客户要求选择。
3.2.2 100V-120V保险丝一般选值计算原则：假定放大器的额定输出功率为W保险丝的电流计算值为AI（单位为安培）保险丝的实际取值为A（单位为安培）其经验计算公式为：AI=11W/590+0.8则A按保险丝的标称电流的优先取值顺序为① A =AI ±0.1②AI +0.1≤A≤AI +0.43.2.3 220V-240V保险丝一般选值原则：保险丝规格电流值以100V-120V保险丝取值的1/2倍取值。
熔断器fuse的型号大全
熔断器的型号有哪些，每个型号上的字母是什么意思，我们可能都不大清楚，就不了解它的功能是什么意思，就有可能用错熔断器，造成不必要的麻烦。
我们在购买熔断器时，是可以提前了解熔断器的型号有哪些，上面的字母代表什么意思，就不会购买错了。
下面由赫森电气给大家介绍一下。
熔断器（fuse）是指当电流超过规定值时，以本身产生的热量使熔体熔断，断开电路的一种电器。
熔断器是根据电流超过规定值一段时间后，以其自身产生的热量使熔体熔化，从而使电路断开；运用这种原理制成的一种电流保护器。
熔断器广泛应用于高低压配电系统和控制系统以及用电设备中，作为短路和过电流的保护器，是应用最普遍的保护器件之一。
表示形式：
T—有填料封闭管式
L—螺旋式、S—快式
LS—螺旋快式
M—无填料封闭管式
C—插入式；
(2) 设计代号；
(3) 熔断器、支持件额定电流；(4) 熔断体额定电流。
如RT18系列：R表示低压熔断器，T表示有填料封闭管式，18表示设计代号。
保险丝选型计算公式(一)
保险丝选型计算公式(一)保险丝选型保险丝（Fuse）是一种用来保护电路的装置，当电路中出现过流情况时，保险丝会断开电路以防止电路过载。
保险丝的选型非常重要，合适的保险丝能确保电路的安全运行。
本文将介绍保险丝选型的相关计算公式，并通过实例说明。
保险丝额定电流保险丝的额定电流是指保险丝可以正常工作的电流大小。
当电路中的电流超过了保险丝的额定电流时，保险丝会熔断以切断电路。
保险丝额定电流的计算公式如下：保险丝额定电流 = 电路最大电流 × 系数其中，系数取决于电路的性质和工作环境，一般在到之间。
示例假设某电路的最大电流为10A，选取保险丝时，假设系数为，则保险丝的额定电流为：保险丝额定电流 = 10A × =因此，应选取额定电流为的保险丝来保护该电路。
保险丝断电时间保险丝断电时间是指保险丝在电流超过额定电流时，多长时间内能够切断电路。
保险丝的断电时间计算公式如下：保险丝断电时间 = 电流系数 × 保护电流 × 保护时间系数其中，电流系数是保险丝动作电流和额定电流之比，保护时间系数取决于所要保护的设备的性质。
示例假设某保险丝的保护电流为10A，选取保险丝时，假设电流系数为，保护时间系数为2，则保险丝的断电时间为：保险丝断电时间 = × 10A × 2 = 30ms因此，该保险丝在电流超过10A时，能够在30毫秒内切断电路。
保险丝能量消耗保险丝能量消耗是指保险丝断电时消耗的能量。
保险丝能量消耗的计算公式如下：保险丝能量消耗 = 保护电流 × 保护电流 × 保险丝动作时间保险丝动作时间是指保险丝断开电路所需的时间。
示例假设某保险丝的保护电流为10A，保险丝动作时间为15ms，则保险丝的能量消耗为：保险丝能量消耗 = 10A × 10A × 15ms =因此，该保险丝在断电时消耗的能量为焦耳。
总结保险丝选型需要考虑额定电流、断电时间和能量消耗等因素。
FUSE选型读后笔记汇总
1．额定电流In：保险丝的额定电流是指它的公称额定电流, 通常就是电路能，够工作的最大电流值正确选择保险丝的额定电流值, 必须作如下考虑电路的工作电流: Ir = 1.5 AUL规格保险丝额定电流应是: In = Ir/Of = 1.5/0.75 = 2A，这儿的Ir是电路工作电流,Of 是UL 规格保险丝的折减率，所以应该选择2A 的保险丝对于IEC规格保险丝则没有折减率要求, 即: Ir = In如果特殊的额定电流不是通用的, 应该选最邻近的较高值。
错误的选泽：把希望保险丝熔断的电流值作为额定电流值2．额定电压Un：保险丝的额定电压是指它的公称额定电压, 通常就是保险丝断开后能够承受的最大电压值正确选择保险丝额定电压应该等于或大于电路电压关于保险丝的额定电压主要应考虑: 当电路电压不超过熔断器额定电压时, 保险丝是否有能力分断给出的最大电流认识的误区：保险丝的额定电压必须跟电路电压一致！3.环境温度：环境温度越高, 保险丝的工作时就越热, 其寿命也就越短不管是UL 规格还是IEC规格, 保险丝的各项指标都是指在25 0C ，如小环境工作温度较高，则要考虑保险丝的温度折减率例: 选用快熔断保险丝在90 0C小环境下和1.5A 电流下工作,参阅下图, 其折减率(Tf) 是95%.若选用IEC规格保险丝, 那么额定电流就是:In = In/ Tf = 1.5A/0.95 = 1,58 A 推荐1.6 A 或2 A 的保险丝若选用UL 规格保险丝那么额定电流就是:In = In/OfxTf = 1.5A/0.75x0.95 = 2.1 A 应选2.5 A 的保险丝曲线A: 传统的慢熔断保险丝曲线B: 特快熔断, 快熔断和螺旋式绕制的保险丝曲线C: 可恢复PTC4.电压降/冷电阻----Ud/R一般情况下，保险丝的电阻值与它的额定电流值成反比在保护电路中要求保险丝阻值越小越好，这样它的损耗功率就小；因此在保险丝技术参数中规定了最大电压降值或冷电阻值，但不作为产品验收依据保险丝的电压降：通以直流额定电流，使保险丝达到热平衡后所得的读数。
FUSE 的选择
电流保险丝应用基本知识一、保险丝的作用：1、正常情况下，保险丝在电路中起连接电路作用。
2、非正常（超负载）情况下，保险丝做为电路中的安全保护元件，通过自身熔断安全切断并保护电路。
二、保险丝的工作原理：保险丝通电时，由电能转换的热量使可熔体的温度上升。
正常工作电流或允许的过载电流通过时，产生的热量通过可熔体、外壳体向周围环境辐射，通过对流、传导等方式散发的热量与产生的热量逐渐达到平衡。
如果产生的热量大于散发的热量，多余的热量就逐渐积聚在可熔体上，使可熔体温度上升；当温度达到和超过可熔体的熔点时，就会使可熔体熔化、熔断而切断电流，起到了安全保护电路的作用。
三、保险丝的分类：1、按外型尺寸分为：φ2、φ3、φ4、φ5、φ6及其它。
2、按熔断特性分为：快速熔断型、中等延时熔断型、延时熔断型。
（还可分特快、强延时）。
3、按分断能力分为：低分断型、高分断型（还可分增强分断型）。
4、按安全标准（或使用地区）分为：UL/CSA（北美）规格、IEC（中国、欧洲等）规格、MIT/KTL（日本/韩国）规格等。
5、其它分类。
四、保险丝的特性术语：1、额定电流：保险丝管的公称工作电流（正常条件下，保险丝长期维持正常工作的最大电流）。
2、额定电压：保险丝的公称工作电压（保险丝断开瞬间，能安全承受的最大电压）。
选用保险丝时，被选用保险丝的额定电压，应大于被保护回路的输入电压。
3、分断能力：当电路中出现很大的过载电流（如强短路）时，保险丝能安全切断（分断）电路的最大电流。
它是保险丝最重要的安全指标。
安全分断是指在分断电路中不发生喷溅、燃烧、爆炸等危及周围元、部件以至人身安全的现象。
4、过载能力(承载能力)：保险丝能在规定时间内维持工作的最大过载电流。
当流经保险丝的电流超过额定电流时，一段时间后熔体温度将逐渐上升以至最后被熔断。
UL标准规定：保险丝维持工作4小时以上，最大不熔断电流是额定电流的110%（微型保险丝管为100%）IEC标准规定：保险丝维持工作1小时以上，最大不熔断电流是额定电流的150%5、熔断特性（I-T）：保险丝所加负载电流与保险丝熔断时间的关系。
从一个实际应用案例来谈Fuse选型
从一个实际应用案例来谈Fuse选型Fuse作为过流庇护器件，已经被广泛地用法在各种电器产品中。
但国内相当多设计开发人员对保险丝器件缺乏足够的认知，选型比较任意，通常只容易考虑下器件的工作/工作参数，就选定了一个规格，因为国内项目通常开发周期较紧要求，工程师的测试重点很少关注到保险丝器件，对其庇护功能和效果未举行充分验证，导致终端产品投入市场后，产品濒临客户各种埋怨：频繁的保险丝选用存在如下几类问题：1, 保险丝电流规格挑选过高，过电流状况下不能准时熔断，保险丝起不到庇护效果导致危急发生；2, 保险丝电流规格挑选过低，正常工作条件下，保险丝即发生熔断，造成产品不能正常工作；3, 保险丝类型挑选错误，其耐冲击能力不够，正常应用之冲击条件下即造成保险丝动作熔断，造成产品无法工作；4, 挑选低端或者假冒品牌保险丝，器件性能不符合自身规定参数。
不能实现应当有的庇护功能。
下面就以一个实际案例，结合TE/FUSE参数特性来谈谈如何挑选一款符合实际应用要求的保险丝：收集终端产品设计/应用对保险丝的要求：- 产品工作温度范围:-40℃to +85℃- 正常工作电压范围: 6V to 18V- 正常工作稳定工作电流=0.36 A/ 正常工作峰值最大电流=1.68A耐脉冲测试要求：- 正常开关发生的脉冲冲击测试要求:Imax=12.94A/持续时光200us/开关次数大于 120,000次;- 24V条件下启动脉冲冲击测试:Imax=27.56A/持续200us/冲击起码5次;- Pulse 1 脉冲冲击 Imax=7A/持续10ms/500次冲击;- Pulse 2a 脉冲冲击Imax=23.38A/持续30us/500次冲击.第1页共2页。
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
1保险丝类1.1保险丝结构介绍一般保险丝由三个部分组成：一是熔体部分，它是保险丝的核心，熔断时起到切断电流的作用，同一类、同一规格保险丝的熔体，材质要相同、几何尺寸要相同、电阻值尽可能地小且要一致，最重要的是熔断特性要一致；二是电极部分，通常有两个，它是熔体与电路联接的重要部件，它必须有良好的导电性，不应产生明显的安装接触电阻；三是支架部分，保险丝的熔体一般都纤细柔软的，支架的作用就是将熔体固定并使三个部分成为刚性的整体便于安装、使用，它必须有良好的机械强度、绝缘性、耐热性和阻燃性，在使用中不应产生断裂、变形、燃烧及短路等现象；电力电路及大功率设备所使用的保险丝，不仅有一般保险丝的三个部分，而且还有灭弧装置，因为这类保险丝所保护的电路不仅工作电流较大，而且当熔体发生熔断时其两端的电压也很高，往往会出现熔体已熔化（熔断）甚至已汽化，但是电流并没有切断，其原因就是在熔断的一瞬间在电压及电流的作用下，保险丝的两电极之间发生拉弧现象。
这个灭弧装置必须有很强的绝缘性与很好的导热性，且呈负电性。
石英砂就是常用的灭弧材料。
参数解释：①．NORMAL OPERATING CURRENT: FUSE所串联回路通过的满载电流②．INTERRUPTING RATING:在保险丝额定电压范围内所允许保险丝安全熔断的电流，目前使用的半导体保护保险的INTERRUPTING RATING一般达到20KA，如果此电流持续时间足够短，Fuse将不会熔断，fuse具有重复承受此冲击的能力。
但是注意，如果短路电流超过此分断电流规格，可能导致FUSE无法正常熔断。
③．VOLTAGE RATING:Fuse所承受的额定电压，如果Fuse熔断后两端的电压差越高，由于内部的拉弧效应，Fuse熔断速度越慢，参考曲线如下：图中K表示I2t的能量系数。
④．TIME-CURRENT CURVE: Fuse 过载能力的查核表，通过电流/时间曲线可以找出fuse在不同电流模式下的过载时间，所有fuse均有此曲线，下图为Ferraz 30A Fuse 的TIME-CURRENT CURVE曲线供参考。
⑤．Fuse 拉弧现象Fuse受冲击电流时均会产生拉弧现象，如果冲击能量>FUSE I2t承受能力，Fuse将发生熔断，参考波形如下：从图中看出，Fuse受冲击时的能量（Total I2t）由melting I2t和Arcing I2t两部分组成。
拉弧的电流（Arcing Current）持续到冲击能量减小到零为止。
拉弧过程的阻抗将抑制在短路回路中电流的增长。
当拉弧阻抗无法抑制住电流的增长时，将发生拉弧故障，将冲击能量超出了上图的灰色区域，此时fuse将熔断。
由于拉弧过程中的阻抗及电流的关系，在拉弧过程中会产生瞬间的拉弧电压，如下图波形：从上图看出，拉弧电压的波形与电压尖峰的波形相同。
1.2分类原则①．按保护分类按保护形式分，可分为：过电流保护与过热保护。
用于过电流保护的保险丝就是平常说的保险丝（也叫限流保险丝）。
用于过热保护的保险丝一般被称为"温度保险丝"。
温度保险丝又分为低熔点合金形与感温触发形还有记忆合金形等等（温度保险丝是防止发热电器或易发热电器温度过高而进行保护的，例如：电吹风、电熨斗、电饭锅、电炉、变压器、电动机等等；它响应于用电电器温升的升高，不会理会电路的工作电流大小。
其工作原理不同于"限流保险丝"）。
②．按使用范围分类按使用范围分，可分为：电力保险丝、机床保险丝、电器仪表保险丝（电子保险丝）、汽车保险丝。
③. 按体积分类按体积分，可分为：大型、中型、小型及微型。
④．按额定电压分类按额定电压分，可分为：高压保险丝、低压保险丝和安全电压保险丝。
⑤．按分断能力分类按分断能力分，可分为：高、低分断能力保险丝。
⑥. 按形状分类按形状分，可分为：平头管状保险丝（又可分为内焊保险丝与外焊保险丝）、尖头管状保险丝、铡刀式保险丝、螺旋式保险丝、插片式保险丝、平板式保险丝、裹敷式保险丝、贴片式保险丝。
⑦.按照熔断速度分类按熔断速度分，可分为：特慢速保险丝（一般用TT表示）、慢速保险丝（一般用T表示）、中速保险丝（一般用M表示）、快速保险丝（一般用F表示）、特快速保险丝（一般用FF表示）。
按标准分，可分为：欧规保险丝、美规保险丝、日规保险丝。
1.3保险丝选择原则保险丝选取从下面几个参数进行考虑：①． 必须符合UPS所对应的安規(Approval)标准；目前UPS的fuse应用主要涉及安规标准为：IEC127和UL 248两个标准。
⑴．UL/CSA/ANCE (Mexico) 248-14 FUSES FOR SUPPLEMENTARYOVERCURRENT PROTECTION标准原文描述如下：UL ampere rating tests are conducted at 100%, 135%, and 200% of rated current. The fuse must carry 110% of its ampere rating and must stabilize at a temperature that does not exceed a 75°C rise at 100%. The fuse must open at 135% of rated current within one hour. It also must open at 200% of rated current within 2 minutes for 0-30 ampere ratings and 4 minutes for 35-60 ampere ratings.最低Interrupt current承受能力需满足下表：⑵．INTERNATIONAL ELECTROTECHNICAL COMMISSION (IEC)Publication 127, Sheet I, II, III, V, VI (250 Volts)标准原文描述如下：IEC Publication 127 defines three breaking capacity levels (interrupting rating). Low breaking capacity fuses must pass a test of 35 amperes or ten times rated current, whichever is greater, while enhanced breaking capacity fuses must pass a test of 150 amperes and finally high breaking capacity fuses must pass a test of 1500 amperes. Sheet I –Type F Quick Acting, High Breaking CapacitySheet II –Type F Quick Acting, Low Breaking CapacitySheet III –Type T Time Lag, Low Breaking CapacitySheet V –Type T Time Lag, High Breaking CapacitySheet VI –Type T Time Lag, Enhanced Breaking CapacityIEC标准中所描述的过载能力如下：在FUSE过载能力的选择上，经验预留1.2倍的余量，保证FUSE过载保护的可靠性。
②．Fuse两端应用的电压必须在额定电压(Voltage Rating)范围之内；③. Fuse所串联的线路通过的满载电流必须低于fuse的额定电流(Current Rating)；Li④．Fuse必须能承受所串联回路的瞬间冲击电流，必须具有分断短路电流的能力；Fuse熔断时的过程如下图所示：一般FUSE选择时均会选取Current-Limiting Fuse，即选取的fuse均有电流的抑制能力，下图为FUSE在线路中遭遇冲击电流时的波形：从上述图片可以看出，FUSE的熔断保护是慢速的，一般至少持续1/2 输入能量的周期。
在FUSE的参数中，Interrupt Rating在FUSE位置的选择至关重要，下图为一般UPS内部应用FUSE的电路参考：其中Main Switch选择的FUSE Interrupt rating至少为125，000A，建议选择rating的等级为200，000A。
在A点的FUSE Interrupt rating至少选为85,000A，建议选择rating的等级为100,000A。
而对于承受冲击电流能力的可靠性来说，A点的FUSE最好选择具有承受200,000A冲击能力的FUSE。
⑤．根据线路的需求选择快斷或慢斷(Fast Acting or Time Delay/Slo-Blo ，区别在于I ²T 的能力)的保险，当Fuse 串联在功率回路上不可避免将遭遇Inrush current 的问题，选择的基础根据经验公式：SCR ：)*(3.0*9.0*3.0*222t I t I T I current Inrush fuse of total component --->=； IGBT&MOSEFT&DIODE：)*(3.0*5.0*3.0*222t I t I T I current Inrush fuse of total component --->= 进行选取，Inrush Current /I ²T的实际波形参考下图：计算I 2t 的数值时，根据冲击波形的形状进行等效能量计算，可参考的下图公式进行相关计算一般fuse均有承受冲击电流次数的限制，不同冲击能量条件下fuse承受的次数不同，具体判断可参考下图：对于大部分的fuse选择来说，fuse正常使用及过载使用的是否安全的判断标准为I2t的数值，具体选用方法根据TIME-CURRENT CURVE曲线查找对应工作电流点的时间常数，根据定义的规格要求判断过载时间是否符合设计要求。
⑥．根据线路可能出现的尖峰电流次数选择具有承受所需脈衝次數(Pulse Behavior)的fuse⑦．根据fuse的应用环境温度情况，选择所需溫度(Temperature)能力的fuse下图为Little fuse不同fuse类别产品的电流&温度曲线：图中可以看出，快速保险相对来说具有较好的current rating 保持特性。
⑧．根据fuse 的封装方式及外部限制条件，选择不同的fuse ，目前主要有几种: FuseClip, Fuse Holder, Pig Tail, DIP , SMD.1.4 保险丝应用介绍1.4.1 保险丝并联运行保险丝并联相当于线路电阻减少一半，此时根据线路分析的原理可以计算出此时并联后两颗fuse 总的fuse parallel t I T I -´=one 222保险丝并联时注意线路layout 的情况，下图为实际摆放参考：放置时注意回路面积比较小，同时线路保持对称。