保险丝培训资料PPT课件

LittelfuseOCSelectionTraining,AnthonyChang,WhoWeAre.,LittelfuseInc.成立於1927年，為專業製造保險絲公司。自1999至2005年投入了過電壓保護元件製造而成為一家線路保護元件的CircuitProtectionProvider的跨國公司。總部設在美國伊利諾州DesPlaines市，擁有十幾家工廠分佈在美、歐、亞三大洲七個國家，在世界各地設有區域性營銷中心。,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,基本保險絲學,保險絲基本工作原理:,結構:金屬熔絲及兩端極功能:保險絲是串聯在電路中,當電路正常工作時,保險絲只相當予一根導線能夠長時間穩定地使用.只有當電路中發生較大的過載電流和或發生短路時保險絲才會熔斷開電流來保護電路的安全.原理:保險絲通電時因電流轉換的熱量會使熔絲的溫度上升.當正常工作電流或允許的過載電流通過時,電流產生的熱量通過熔絲,殼體向周圍環境輻射,通過對流和傳導等方式散發的熱量能與產生的熱量逐漸達到平衡.當散熱速跟不上發熱時這些熱量就會在熔絲上逐漸累積,使溫度上升,一旦溫度達到和超過熔絲材料的熔點時會使熔絲熔化而斷開電流,達到保護的作用.,保險絲允許的過載能力(FuseCurrentCapacity),Max.Carryingcurrent:ULSTD保險絲的最大不熔斷電流是75%In；IECSTD保險絲的最大不熔斷電流是100%In。同時也要求保險絲在超過限量的過載電流時能及時燒斷，其中:MinimumFusingCurrent:ULSTD保險絲的最小熔斷電流在200%In左右；IECSTD保險絲的最小熔斷電流在210%左右。,Cold,HOT,選用保險絲的重要參數(Fuseselectionfactors),選擇的保險絲是主要或次要的保護元件?(FuseforPrimaryorSecondaryProtection?)1。額定電流(Ratedcurrent)(Minimumfuserating)=In2。額定電壓(Ratedvoltage)AC/DC3。應用環境温度(Ambienttemperature)4。電壓降(Voltagedrop)5。熔斷特性(Fusingcharacteristics)-時間/電流特性(TCcurves),6。遮斷/分斷能力(Breaking/InterruptingCapacity)7。熔化熱能值(MeltingIt)8。結構特徵(Structure)-外形尺寸-安裝型式,额定電流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規格保險絲：In=Ir/(Frf*Tdf)IEC規格保險絲:In=Ir/Tdf計算的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额定電流值。,應用環境温度(AmbientTemperature),UL/IEC保險絲的各项要求都是指在室温條件下-250C時應用環境温度對保險絲的特性是有很大的影響!温度折减率-TdfAmbientTemp:referstotheairtemperatureimmediatelytothevicinityoffuse.(Note:AttheworstConditionsuchasBurnIn,hightemptest,etc.),實例:應用電壓:12VDC應用最大/重載電流:1Amax環境溫度緊鄰保險絲:80C脈衝電流:20A30uSec.*短路電流:35Amax.at12V保險絲種類:1206sizeTFF應用最大電流是1.0A就將此值帶入下述公式:,Tdf:0.75*(0.70),Example:,Example:Steadystatecurrent,應用最大電流(Irmax)1.0ACat.FuseRating=-=-0.75x溫度折減率(Tdf)80C0.75x0.70Cat.FuseRating=1.91A計算值-Absoluteminimumfuseratingcanbeselected.(可從1206size的466or468系列2A以上安培數,請參考表(一)。)表(一)P/NRatingVoltageMeltingI2t04660022.0A63V0.2326A2Sec046602.52.5A32V0.3516A2Sec04660033.0A32V0.5760A2Sec04680022.0A63V0.506A2Sec04680033.0A32V1.270A2Sec,Example:(Continue),额定電壓RatedVoltage(Vr）,保險絲的额定電壓應大於或等於應用電路電壓(Vr標示在保險絲目錄上)正常負載時额定電壓對保險絲影響很小過載熔斷時额定電壓對保險絲有影響,FUSING,Basics:Hotspot,温度Temperature(C),負載電流時的溫度,PCBSn锡球PCB,In,IIn,MeltingPoint,t=0,t=1fusingtomelting,fusing,BasicFusingProcess(保險絲熔斷過程),t=1,t=3arcingcontinuedependedontheIandV，,Arcingend,t=2,arcingstarting,BasicFusingProcess(保險絲熔斷過程),保險絲的電壓降說明,保險絲的電壓降是保險絲在額定電流條件下，其兩端的電壓降。它反映了保險絲的內阻，其值不應過大。若將內阻（電壓降）過大的保險絲安裝在電路中，它將影響電路的系統參數，使得電路不能正常工作。標準對電壓降不僅有其值的上限規定，而且對其一致性也作了規定。,時間/電流特性Time/CurrentCharacteristic,承受過電流時,電流與熔斷時間的關係Itisacharacteristicsdeterminehowfastafuserespondstoover-currents.Over-currentisdividedintooverloadsandshortcircuits.UL和IEC的熔斷特性是完全不同的,UL/CSA248-14規格ULVsIEC60127規格（）,AGENCYAPPROVALS,UL/CSA248-14ListedCompliedUL/CSA248-14Recognized-ManufacturerIEC60127Certifyagency:VDE,BSI,SEMKO,TUV,NemKoMETIPSEMarkingCCCChinaSafetyperIECK-markKoreanSafety,時間vs.電流曲線:(Timevs.Currentcurve),T/CCurve是一個供設計參考用的工具而不是保險絲的規範是保險絲一個的平均熔斷時間曲線圖.實際熔斷時間必須考量實際供應電壓.,如何看讀時間/電流曲線(HowtoreadtheTCcurve),先選3A曲線.找出3曲線與6A線交叉點.後再往Y軸讀取相應時間-0.1seconds.,.18012357.515,遮斷/分斷能力(Breaking/InterruptingCapacity),在額定電壓條件下,保險絲能夠安全地分斷預期的電流且沒有對環境的損害.(InterruptingratingalsoknownasBreakingCapacityorshortcircuitrating,theinterruptingratingisthemaximumapprovedcurrentwhichthefusecanSAFELYinterruptatratedvoltage.)保險絲最重要的安全指標(Theword“safely”heremeansthatthereshouldbenosignificantdamagetothefusehousingnortothesurroundingsasaresultofarcingormoltenmetalemergingfromthefuse.)短路時保險絲能安全分斷的最大短路電流IECSTDFuseType有分高分斷(HighBreakingCapacity)，中分斷(EnhanceBreakingCapacity)和低分斷(LowBreakingCapacity)保險絲.,遮斷/分斷能力(Breaking/InterruptingCapacity),UL248-14規定的分斷能力:125VAC條件下ULListed保險絲必須能切斷10,000AforSubminiaturefuse(2AG)的電流;250VAC條件下保險絲必須能切斷的電流如下:保險絲的額定電流額定分斷能力01A35A1.13.5A100A3.69A200A10.115A750A15.130A1500ARemark:Recognized認證的保險絲直接參考製造商的InterruptingRating規格,遮斷/分斷能力(Breaking/InterruptingCapacity),IEC127規定的分斷能力:250VAC條件下的分斷能力保險絲-低分斷(LBC)必須能安全切斷35AMINIMUM或它的10In中的最大的電流;中分斷(EBC)必須能安全切斷150A的電流;高分斷(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),切斷保險絲所需的熱能量值*(isadirectmeasurefortheenergyrequiredtoblowthefuse-element.)often,thefusenominalmeltingItMethodoffuseselectionisappliedtothoseapplicationsinwhichthefuseMUSTsustainlargecurrentpulsesofashortduration.選用保險絲规格的重要参数(mostimportantfuseselectionfactor)防疲勞,多次的擴散,氧化(preventde-grade,andoxidize,etc.)力特對每一種小型保險絲给出了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(計算單脈衝I2t值)=(20A)2x30uSec=0.12A2Sec/2=0.06A2Sec(請參照LFsDesignersGuidewaveformC,onpage6,chartI,如下Note:最佳以方形波計算單脈衝PulseI2t值),C,CalculatedMeltingI2t(計算熱熔能量值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