保險(xiǎn)絲培訓(xùn)資料PPT課件

LittelfuseOCSelectionTraining,AnthonyChang,WhoWeAre.,LittelfuseInc.成立於1927年，為專業(yè)製造保險(xiǎn)絲公司。自1999至2005年投入了過電壓保護(hù)元件製造而成為一家線路保護(hù)元件的CircuitProtectionProvider的跨國公司?？偛吭O(shè)在美國伊利諾州DesPlaines市，擁有十幾家工廠分佈在美、歐、亞三大洲七個(gè)國家，在世界各地設(shè)有區(qū)域性營銷中心。,1927Firstinstrumentfuses1976ATObladefuse1992Surfacemount(D-Case)1994SquareNanofuse1994A-Case(1206)19960603surfacemount1997PTCResettableDevice1999ESDProtectors/HarrisSuppression2002LeadFree1206,0603therebyhaltingtheovercurrentcondition.,FuseReview:Construction,TraditionalCartridgeTypeVs.SlimlineThinFilmType,Cartridgefuse,ThinFilmfuse,Themetallicelement(filament)meltsanddisconnectsthepowertothecircuit.,SMDFuse1.-CeramicBody.2.-FuseendcapsTin-LeadandRoHS(SilverorGold)platedcaps.3.-Filament(AgAlloy)for451wire-in-airdesignminimizesthermalde-ratingfactorandextendsusabletemperaturerange.,Fuse,Nano2UMFfuse,TeleLinkfuse,Nano2fuse,ChipfusesBatterypackHarddiskdriveCellphoneDigitalcameraLCDmonitorinverter(smallpanels)MP3/PMPplayerBluetoothheadset,Wire-in-AirSMDfusesMotherboards(servers,notebooks)LCDmonitorinverter(largepanels)Telecomequipment(TeleLink)AutomotiveElectronicsmodulesTelematics,climatecontrol,navigation,bodycontrollers,Targetapplications:,Protectionofinvertercircuit(LCD),Inverter,Fuse,Inverter,WhatisaFUSE?,1.Afuseisathermallyrespondingdevice.Afuseisdesignedandmanufacturedtoprotectbybeingtheintentionalweaklinkinanelectricalcircuit.PurposeofthefuseistopreventFIRE!,Fusing,UltimateSystem,End,基本保險(xiǎn)絲學(xué),保險(xiǎn)絲基本工作原理:,結(jié)構(gòu):金屬熔絲及兩端極功能:保險(xiǎn)絲是串聯(lián)在電路中,當(dāng)電路正常工作時(shí),保險(xiǎn)絲只相當(dāng)予一根導(dǎo)線能夠長時(shí)間穩(wěn)定地使用.只有當(dāng)電路中發(fā)生較大的過載電流和或發(fā)生短路時(shí)保險(xiǎn)絲才會(huì)熔斷開電流來保護(hù)電路的安全.原理:保險(xiǎn)絲通電時(shí)因電流轉(zhuǎn)換的熱量會(huì)使熔絲的溫度上升.當(dāng)正常工作電流或允許的過載電流通過時(shí),電流產(chǎn)生的熱量通過熔絲,殼體向周圍環(huán)境輻射,通過對(duì)流和傳導(dǎo)等方式散發(fā)的熱量能與產(chǎn)生的熱量逐漸達(dá)到平衡.當(dāng)散熱速跟不上發(fā)熱時(shí)這些熱量就會(huì)在熔絲上逐漸累積,使溫度上升,一旦溫度達(dá)到和超過熔絲材料的熔點(diǎn)時(shí)會(huì)使熔絲熔化而斷開電流,達(dá)到保護(hù)的作用.,保險(xiǎn)絲允許的過載能力(FuseCurrentCapacity),Max.Carryingcurrent:ULSTD保險(xiǎn)絲的最大不熔斷電流是75%In；IECSTD保險(xiǎn)絲的最大不熔斷電流是100%In。同時(shí)也要求保險(xiǎn)絲在超過限量的過載電流時(shí)能及時(shí)燒斷，其中:MinimumFusingCurrent:ULSTD保險(xiǎn)絲的最小熔斷電流在200%In左右；IECSTD保險(xiǎn)絲的最小熔斷電流在210%左右。,Cold,HOT,選用保險(xiǎn)絲的重要參數(shù)(Fuseselectionfactors),選擇的保險(xiǎn)絲是主要或次要的保護(hù)元件?(FuseforPrimaryorSecondaryProtection?)1。額定電流(Ratedcurrent)(Minimumfuserating)=In2。額定電壓(Ratedvoltage)AC/DC3。應(yīng)用環(huán)境溫度(Ambienttemperature)4。電壓降(Voltagedrop)5。熔斷特性(Fusingcharacteristics)-時(shí)間/電流特性(TCcurves),6。遮斷/分?jǐn)嗄芰?Breaking/InterruptingCapacity)7。熔化熱能值(MeltingIt)8。結(jié)構(gòu)特徵(Structure)-外形尺寸-安裝型式,額定電流RatedCurrent(In),額定電流In=Irmax/(Frf*Tdf)最大/重載工作電流(maxoperatingcurrentIrmax*)ULre-ratingfactor:Frf-0.75IECre-ratingfactor:Frf-1Temperaturede-ratingfactor,TdfrefertotemperaturecurveA,BorC,UL規(guī)格保險(xiǎn)絲：In=Ir/(Frf*Tdf)IEC規(guī)格保險(xiǎn)絲:In=Ir/Tdf計(jì)算的In是Absolute最小的In額定電流值可選或往上選用最佳適用的In額定電流值。,應(yīng)用環(huán)境溫度(AmbientTemperature),UL/IEC保險(xiǎn)絲的各項(xiàng)要求都是指在室溫條件下-250C時(shí)應(yīng)用環(huán)境溫度對(duì)保險(xiǎn)絲的特性是有很大的影響!溫度折減率-TdfAmbientTemp:referstotheairtemperatureimmediatelytothevicinityoffuse.(Note:AttheworstConditionsuchasBurnIn,hightemptest,etc.),實(shí)例:應(yīng)用電壓:12VDC應(yīng)用最大/重載電流:1Amax環(huán)境溫度緊鄰保險(xiǎn)絲:80C脈衝電流:20A30uSec.*短路電流:35Amax.at12V保險(xiǎn)絲種類:1206sizeTFF應(yīng)用最大電流是1.0A就將此值帶入下述公式:,Tdf:0.75*(0.70),Example:,Example:Steadystatecurrent,應(yīng)用最大電流(Irmax)1.0ACat.FuseRating=-=-0.75x溫度折減率(Tdf)80C0.75x0.70Cat.FuseRating=1.91A計(jì)算值-Absoluteminimumfuseratingcanbeselected.(可從1206size的466or468系列2A以上安培數(shù),請(qǐng)參考表(一)。)表(一)P/NRatingVoltageMeltingI2t04660022.0A63V0.2326A2Sec046602.52.5A32V0.3516A2Sec04660033.0A32V0.5760A2Sec04680022.0A63V0.506A2Sec04680033.0A32V1.270A2Sec,Example:(Continue),額定電壓RatedVoltage(Vr）,保險(xiǎn)絲的額定電壓應(yīng)大於或等於應(yīng)用電路電壓(Vr標(biāo)示在保險(xiǎn)絲目錄上)正常負(fù)載時(shí)額定電壓對(duì)保險(xiǎn)絲影響很小過載熔斷時(shí)額定電壓對(duì)保險(xiǎn)絲有影響,FUSING,Basics:Hotspot,溫度Temperature(C),負(fù)載電流時(shí)的溫度,PCBSn錫球PCB,In,IIn,MeltingPoint,t=0,t=1fusingtomelting,fusing,BasicFusingProcess(保險(xiǎn)絲熔斷過程),t=1,t=3arcingcontinuedependedontheIandV，,Arcingend,t=2,arcingstarting,BasicFusingProcess(保險(xiǎn)絲熔斷過程),保險(xiǎn)絲的電壓降說明,保險(xiǎn)絲的電壓降是保險(xiǎn)絲在額定電流條件下，其兩端的電壓降。它反映了保險(xiǎn)絲的內(nèi)阻，其值不應(yīng)過大。若將內(nèi)阻（電壓降）過大的保險(xiǎn)絲安裝在電路中，它將影響電路的系統(tǒng)參數(shù)，使得電路不能正常工作。標(biāo)準(zhǔn)對(duì)電壓降不僅有其值的上限規(guī)定，而且對(duì)其一致性也作了規(guī)定。,時(shí)間/電流特性Time/CurrentCharacteristic,承受過電流時(shí),電流與熔斷時(shí)間的關(guān)係Itisacharacteristicsdeterminehowfastafuserespondstoover-currents.Over-currentisdividedintooverloadsandshortcircuits.UL和IEC的熔斷特性是完全不同的,UL/CSA248-14規(guī)格ULVsIEC60127規(guī)格（）,AGENCYAPPROVALS,UL/CSA248-14ListedCompliedUL/CSA248-14Recognized-ManufacturerIEC60127Certifyagency:VDE,BSI,SEMKO,TUV,NemKoMETIPSEMarkingCCCChinaSafetyperIECK-markKoreanSafety,時(shí)間vs.電流曲線:(Timevs.Currentcurve),T/CCurve是一個(gè)供設(shè)計(jì)參考用的工具而不是保險(xiǎn)絲的規(guī)範(fàn)是保險(xiǎn)絲一個(gè)的平均熔斷時(shí)間曲線圖.實(shí)際熔斷時(shí)間必須考量實(shí)際供應(yīng)電壓.,如何看讀時(shí)間/電流曲線(HowtoreadtheTCcurve),先選3A曲線.找出3曲線與6A線交叉點(diǎn).後再往Y軸讀取相應(yīng)時(shí)間-0.1seconds.,.18012357.515,遮斷/分?jǐn)嗄芰?Breaking/InterruptingCapacity),在額定電壓條件下,保險(xiǎn)絲能夠安全地分?jǐn)囝A(yù)期的電流且沒有對(duì)環(huán)境的損害.(InterruptingratingalsoknownasBreakingCapacityorshortcircuitrating,theinterruptingratingisthemaximumapprovedcurrentwhichthefusecanSAFELYinterruptatratedvoltage.)保險(xiǎn)絲最重要的安全指標(biāo)(Theword“safely”heremeansthatthereshouldbenosignificantdamagetothefusehousingnortothesurroundingsasaresultofarcingormoltenmetalemergingfromthefuse.)短路時(shí)保險(xiǎn)絲能安全分?jǐn)嗟淖畲蠖搪冯娏鱅ECSTDFuseType有分高分?jǐn)?HighBreakingCapacity)，中分?jǐn)?EnhanceBreakingCapacity)和低分?jǐn)?LowBreakingCapacity)保險(xiǎn)絲.,遮斷/分?jǐn)嗄芰?Breaking/InterruptingCapacity),UL248-14規(guī)定的分?jǐn)嗄芰?125VAC條件下ULListed保險(xiǎn)絲必須能切斷10,000AforSubminiaturefuse(2AG)的電流;250VAC條件下保險(xiǎn)絲必須能切斷的電流如下:保險(xiǎn)絲的額定電流額定分?jǐn)嗄芰?1A35A1.13.5A100A3.69A200A10.115A750A15.130A1500ARemark:Recognized認(rèn)證的保險(xiǎn)絲直接參考製造商的InterruptingRating規(guī)格,遮斷/分?jǐn)嗄芰?Breaking/InterruptingCapacity),IEC127規(guī)定的分?jǐn)嗄芰?250VAC條件下的分?jǐn)嗄芰ΡｋU(xiǎn)絲-低分?jǐn)?LBC)必須能安全切斷35AMINIMUM或它的10In中的最大的電流;中分?jǐn)?EBC)必須能安全切斷150A的電流;高分?jǐn)?HBC)必須能安全切斷1500A的電流,EXAMPLE:(continue),0466seriesInterruptingrating50A63VAC/DCfor0.52.0A0466seriesInterruptingrating50A32VAC/DCfor2.53A0466seriesInterruptingrating50A24VAC/DCfor45A0468seriesInterruptingrating35A63VAC/DCfor2A0468seriesInterruptingrating50A32VAC/DCfor3A,熔化熱能值(MeltingI2t),切斷保險(xiǎn)絲所需的熱能量值*(isadirectmeasurefortheenergyrequiredtoblowthefuse-element.)often,thefusenominalmeltingItMethodoffuseselectionisappliedtothoseapplicationsinwhichthefuseMUSTsustainlargecurrentpulsesofashortduration.選用保險(xiǎn)絲規(guī)格的重要參數(shù)(mostimportantfuseselectionfactor)防疲勞,多次的擴(kuò)散,氧化(preventde-grade,andoxidize,etc.)力特對(duì)每一種小型保險(xiǎn)絲給出了FuseNominal熔化I2t值清除I2t=熔化I2t+飛弧I2tClearingI2t=MeltingI2t+ArcingI2t*Ratio22%=PulseI2t/FuseMeltingI2t*SelecteitherF-fast-actingorT-timelaggedfuse*Thesehigh-energycurrentsarecommoninmanyapplicationsandaredescribedbyavarietyofterms,suchas“surgecurrent”,“start-upcurrent”,“Inrushcurrent”,andothersimilarcircuit“transients”thatcanbeclassifiedingeneralcategoryof“PULSES.”Pulsecurrenti.e.aflowofrepetitivecurrentpulses.,PulseIt=ip(t)dt=ip(t)0SafetyfactorisLessthan22%=PulseIt/FuseNominalMeltingItORFuseminimumMeltingIt=PulseIt/22%,I2tofanArbitraryPulse-Conceptually,I2t=areaunderi2(t)curve,i(t),Time(t),Current(A),t1,t2,i2(t),Time(t),Current(A),t1,t2,i2(t),MeltingI2t,MeltingI2tisanindexthatcharacterizestheenergyrequiredtomeltafuseelement.MeltingI2tvaluesareempiricallymeasuredasshown:,Current(A),Time,meltingtime,arcingtime,Elementmelted,Arcingbegins,IntegratedtocalculateMeltingI2t,ExampleofInrushCurrent,Ip2,Ip1,Ip3,t1,t2,t3,t4,t5,Ir=4.5A,ExampleofInrush,Ip1=25AIp2=20AIp3=25AT1=3mSecT2=10SecT3=3mSecT4=1hourT5=5mSecPulseI2t1=Ip1xIp1xt1=25x25x3mSec=1.875A2SecPulseI2t2=Ip2xIp2x(t3-t2)=20 x20 x3mSec=1.2A2Sec.PulseI2t3=Ip3xIp3x(t5t4)=25Ax25Ax5mSec=3.125A2SecTotalPulseI2t=6.2A2Sec(3.1A2Sec)FuseMeltingI2t=TotalPulseI2t/0.22100,000cycles=28.2A2Sec(14.1A2Sec)Fuserating,In=Ir/(safetyfactor*Temperaturefactor)ULfactor=0.75,IECfactor=1,Temperature=100CFuserating,In=4.5/(0.75x0.9)=6.67AforULtypefuseminimum.In=4.5/(1x0.9)=5AforIECtypeminimum.,Example(continue):PulseI2tcalculation,T：30secIp：Max20APulseI2t=（Ip2T）（202030sec）=0.12A2Sec(AssumeworstinrushconditionofSquarewaveform*)100000PulsesFactor：0.22safetyfactorFuseMeltingI2t=PulseI2t/0.22=0.12/0.22=0.5455A2Sec,CalculatedPulseI2t(計(jì)算單脈衝I2t值)=(20A)2x30uSec=0.12A2Sec/2=0.06A2Sec(請(qǐng)參照LFsDesignersGuidewaveformC,onpage6,chartI,如下Note:最佳以方形波計(jì)算單脈衝PulseI2t值),C,CalculatedMeltingI2t(計(jì)算熱熔能量值I2t)=0.120.22=0.5455A2Sec*(Per“A”)=0.06/0.22=0.273A2Sec*(Per“C”)%ratio=0.06/0.2326=0.258=25.8%-NG(52%)%ratio=0.06/0.3516=0.171=17.1%-OK(34.2%)%ratio=0.06/5716=0.105=10.5%-OK(21%)%ratio=0.06/506=0.119=11.9%-OK(23.8%)%ratio=0.06/1.27=0.048=4.8%-OK(9.5%),Example(Continue):PulseI2TRecycle;Recoveryby2006!,ResettablePTCs,ResettablePTC,PTCoperationResistanceislowduringnormalcircuitoperationandincreasesduringovercurrentevents,Solutionsfor:Poweredplug-and-playportovercurrentprotection,ResettablePTCSurfacemountandradialleadedformfactorsAmperageratingsfrom0.10Ato9.0ASurfacemountpartsavailableinsizesof1206and1812.Keyfeatureistheabilitytoresetitself(returntolowresistancestate)andreconnectpoweraftertheovercurrentconditionhasbeencleared,ResettablePTC,ResettablePTCsBatterypackCellphoneDigitalcameraMotherboardsUSB,FireWire(DCbus)AdaptercardsPoweredEthernetportsTip/ringcircuits,Targetapplications:,USBportprotection,ResettablePTC,Tip/ringprotection,DCportprotection,UnderNormalOperation,UnderAFaultCondition,Atope