Touch Leakage Current接触电流ppt课件

Touch(Leakage)Current,ST07,Version3.0,OverallSessionObjectives:1.TounderstandtherationalefortheTouch(leakage)CurrentTest,instrumentation,connections,testproceduresandlimits2.Tounderstandlimitationsoftestandalternativeapproaches,Touch(Leakage)Current,Touch(Leakage)CurrentTopicsDefinitions(UL101,IEC60990)TouchcurrentpathsPhysiologicaleffectsoftouchcurrent(electricshock)Bodyimpedancemodelsand“safe”voltagelimitsTouch(Leakage)CurrentTest,Touchcurrentinstruments(meters)MeasurementcircuitsandproceduresLimitsSpecialSituations,DEFINITIONSLEAKAGECURRENT(UL101-2002):Electriccurrentwhichflowsthroughapersonuponcontact,betweenaccessiblepartsofanapplianceand(1)ground,or(2)otheraccessiblepartsoftheapplianceTOUCHCURRENT(IEC60990):Electriccurrentthroughahumanbodyorananimalbodywhenittouchesoneormoreaccessiblepartsofaninstallationorofequipment.,Touch(Leakage)CurrentPaths,Accessiblemetal,Load,Load,ElectricalinsulationSystem,L,N,G,+,_,UngroundedConductor,GroundedConductor,Grounding(protectiveearthing)Conductor,?,Touchcurrent,ReturnPath,TouchCurrentPaths,Load,Load,Example:Ungrounded2wireCordandPlug-ConnectedAppliances,touchablemetal,ElectricalInsulationSystem,ToElectricalSupply,Canopener,Toasteroven,TV,radio,Coffeemaker,iron,blender,Examplesof2-wireNon-GroundedAppliances,TouchCurrentPaths,Touchablemetal,Load,Load,Ungrounded2wireappliance,TouchableMetalofGroundedAppliances,ElectricalinsulationSystem,EquipmentGroundingConductor(protectiveearthingconductor),G,L,N,G,+,_,UngroundedConductor,GroundedConductor,Grounding(protectiveearthing)Conductor,ReturnPaths,dishwasher,range,microwave,refrigerator,Examplesof3-wireGroundedAppliances,Canopener,Toasteroven,TV,radio,Coffeemaker,iron,blender,Examplesof2-wireNon-GroundedAppliances,ConstructionGrounds,MetallicPipingSystem,Bondingconnectiontowaterpipe,Touchablemetal,Load,Load,Ungrounded2wireappliance,ElectricalinsulationSystem,G,L,N,G,+,_,UngroundedConductor,GroundedConductor,Grounding(protectiveearthing)Conductor,ReturnPaths,TouchCurrentPaths,Sink,ExamplesofConstructionGrounds,Baseboardheating,Examplesof3-wireGroundedAppliances,Examplesof2-wireNon-GroundedAppliances,dishwasher,range,microwave,refrigerator,Canopener,Toasteroven,TV,radio,Coffeemaker,iron,blender,TouchCurrentPaths,Ungrounded2wireappliance,Load,Load,Pathwaythroughearth,Touchablemetal,ElectricalinsulationSystem,Soil,L,N,G,+,_,UngroundedConductor,GroundedConductor,Grounding(protectiveearthing)Conductor,ReturnPaths,TouchCurrentPaths,Touchablemetal,Load,Load,ElectricalinsulationSystem,L,N,G,+,_,UngroundedConductor,GroundedConductor,Grounding(protectiveearthing)Conductor,Example:Three-WireGroundedCordandPlugConnectedproduct,TouchCurrentPaths,2-wirereceptacle(normal-oldconstruction),OR,ConnectiontoUngroundedReceptacle,Touchablemetal,Load,ElectricalinsulationSystem,L,N,G,+,_,UngroundedConductor,GroundedConductor,Grounding(protectiveearthing)Conductor,Example:Three-WireGroundedCordandPlugConnectedproduct,Opencircuitorhighimpedance(fault),TouchCurrentPaths,touchablemetal,Load,L,N,G,+,_,UngroundedConductor,GroundedConductor,Grounding(protectiveearthing)Conductor,TouchCurrentFromSimultaneouslyTouchablePartsofsameproduct,Touch(Leakage)CurrentTopicsDefinitions(UL101,IEC60990)TouchcurrentpathsPhysiologicaleffectsoftouchcurrent(electricshock),PhysiologicalEffectsofTouchCurrent(sinusoidal,rms,60Hz),Perception(microamperesto0.5mA),Startlereaction(0.5mA),Muscletetanization(inabilitytoletgo)(5mA),Ventricularfibrillation(50mA),Electricalburns(70mA),V10-001,0.5,1,5,10,10,20,35,VentricularFibrillation,Let-Go,I=0.954f,0.716,f70Hz,IECThresholdULLimit,EffectsofFrequencyonElectricShockThresholdsandLimitsforContinuousACcurrent,BodyCurrent(rmsmA),Frequency(Hz),2,1.threshold/limit=2mAat0Hz(dc),(seenote3),3.respiratoryarrestobservedindogsat20,30,and40mA,CurrentDensity,Duration*,Pathwaythroughbody,V10-015,(skincontactlocation),OtherTouchCurrentVariables,*SeeSpecialSituationsforTouchCurrentMeasurements,Waveshape*,Touch(Leakage)CurrentTopicsDefinitions(UL101,IEC60990)TouchcurrentpathsPhysiologicaleffectsoftouchcurrent(electricshock)Bodyimpedancemodelsand“safe”voltagelimits,+,_,=sourceopencircuitvoltage,=sourceimpedance,(,=,f,.),+,=,DeterminingTouchCurrent,VoltageSource,C,2,FiveComponentBodyImpedanceModel,Impedancerepresentingoneskin-electrodecontact,Internalbodyimpedance(lesstheskin),Impedancerepresentingotherskin-electrodecontact,FactorsAffectingBodyImpedance,conditionofskin(affectsR1andR2),otherfactors:,pressureofskincontacttypeofskindurationofcontacttemperatureofskin,currentpathwaythroughbody(affectsR3),bodysizeandshape(affectsR3),voltageacrossthebody(affectsR1andR2),areaofskincontact(affectsR1,R2,C1andC2),C,2,Impedancerepresentingoneskin-electrodecontact,Impedancerepresentingotherskin-electrodecontact,Internalbodyimpedance(lesstheskin),EffectofCurrentPathwayonInternalBodyImpedance,Whatistheinternalbodyimpedance:Handtohand?_ohmsOnehandtobothfeet?_ohmsBothhandstobothfeet?_ohms,CLASSEXERCISE:,10,20,50,1000,500,200,100,100,10000,5000,2000,1000,500,200,Totalbodyimpedance(ohms),50/60HzACvoltage(vrms),95%,5%,Effectofvoltageontotalbodyimpedance,currentpathhandtohand,forlargesurfaceareasofcontact,dryskin(basedonIEC60479),Experiment,600,750,6000,5000,4000,3000,2000,1000,0,2000,500,100,50,1000,Frequency(Hz),EffectofFrequencyonTotalBodyImpedance,1,1.FromIEC60479.Totalbodyimpedanceofapopulationforapercentilerankof50%Currentpathhandtohandorhandtofoot,dryskinconditions,largeareacontact,10Va.c.,25V,50V,100V,220V,.,TotalBodyImpedance,K,TouchAreaofContact,examplefortypicaladultmale(handtohand,dryskin,25-150vac,50Hz),(basedonIEC60479-1),25vac,25vac,25vac,25vac,25vac,150vac,150vac,150vac,150vac,150vac,tipofsmallwire,palmofhand,forefingerpad,Effectofsurfaceareaofcontactontotalbodyimpedance,ohms,SimplifiedBodyImpedanceModels,3-componentmodelfordry-moistcontactandlowtouchvoltage,Conservativemodelforlowskinimpedance(e.g.,wetcontact,highvoltages,and/orhighfrequency),0.22Microfarad,1500ohms,500ohms,500ohms,Combinationtwolargeareaskincontacts,Internalbodyimpedance,E=IxZ,FrequencyinHertz,10,10,10,100,100,100,1000,1000,1000,10,000,10,000,10,000,BodyCurrentThresholdforLet-Go,AppliedVoltageThresholdForLet-Go,BodyImpedance,Z,I,CombinedEffectsofFrequencyonBodyImpedanceandElectricShockThresholds,FrequencyinHertz,FrequencyinHertz,ExamplesofSafeVoltageCriteria(Checkthespecificend-productstandard),15VACrms(100Hz)30VDC,30VACrms(100Hz)60VDC,42.4Vpeak(100Hz)(includingdc),42.4Vpeak(100Hz)60VDC,71Vpeak(0.2sec,singlefaultconditionsfortime0.2sec,Let-goandfibrillation,drylocations(UL,NEC),Let-goandfibrillation,wetlocations,notincludingimmersion(UL,NEC),ElectricalInsulation:BasicEquipmentSafeguardAgainstElectricShock,+,_,Vs,Zs,ZB,ZI,IT,Hazardousvoltageandcurrentsource:,VSexceeds“safe”voltageAND,IS=VS/Zsexceeds“safe”availablecurrent,IS,IS=availablesourcecurrent,Electricalinsulationmodel,InsulationResistanceTest,Touch(Leakage)CurrentTest,DielectricWithstandTest(Hi-pot),BasicTestsonElectricalInsulation,Touch(Leakage)CurrentTopicsDefinitions(UL101,IEC60990)TouchcurrentpathsPhysiologicaleffectsoftouchcurrent(electricshock)Bodyimpedancemodelsand“safe”voltagelimitsTouch(Leakage)CurrentTest,Touchcurrentinstruments(meters),Touch(Leakage)CurrentTest,Accessiblemetal,Load,Load,ElectricalinsulationSystem,L,N,G,+,_,UngroundedConductor,GroundedConductor,Grounding(protectiveearthing)Conductor,applieswhensourceexceeds“safe”voltagelevels,representbodyimpedanceasfunctionoffrequency,representphysiologicaleffectasafunctionoffrequency,RationaleforLimitsRationaleforFlexibleMetalFoilRationaleforProductsRequiringEMIFilteringtoMeetFCCRequirementsRationaleforHumidityConditioningRationaleforHigherLeakageCurrentLevelsRationaleforChoiceofMeter,andAlternativeMetersRationaleforMeasurementCircuits,UL101-LeakageCurrentforAppliances,SelectionofMeasurementInstrument,InstrumentSpecifications,ANSIC101-1986-AverageRespondingSystem(ARS)(StillspecifiedinmostULstandards),UL101-2002(ReplacedANSIC101)(SpecifiedinsomeULendproductstandardsandmostharmonizedULstandards),IEC60990-1999,SPECIFICATIONSFORREACTION:,SPECIFICATIONSFORLET-GO:,IEC609901999,SPECIFICATIONSFORELECTRICALBURNS:,IEC60990-1999,UL101-2002,(0.5mArmslimit60Hz),(3.5mArms,5mArmslimits60Hz),(70mArms),Ammeter(averageresponding),MeasurementInstrumentSpecificationsforReaction,(ANSIC101-1986),(a)Inputimpedance(Z),(b)Metertypeandlocation,(intendedtocombineeffectoffrequencyonbodyimpedanceandphysiologicalresponse),AverageRespondingSystem(ARS),Voltmeter(averageresponding),(d)Circuitfrequencyresponse(0to100kHz),IA,IA=actualcurrenttonetwork,I1=indicatedcurrenttonetwork(=V1/R1rmsforsinusoid),Z=R1parC1,(0-100kHz),Indication(current)=1.11xVM(ave)/1500,I1,=I1=V1/R1(rmsforsinusoid),(c)Meterindication,Max5%errorindicationof0.75mA,MeasurementInstrumentSpecificationsforReaction,(ANSIC101-1986),(a)Inputimpedance(Z),(b)Metertypeandlocation,(combineseffectoffrequencyonbodyimpedanceandphysiologicalresponse),AverageRespondingSystem(ARS),SimpsonModel229(ANSIC101-1986),R1,C1,Revisedbodyimpedancemodel,Voltmeter,Frequencysensitivenetworkforreaction,RevisedMeasurementInstrumentforReaction,UL101-2002,IEC60990-1999,Rmsreading(ANSIC101),Peakreading(IEC60990),R1,C1,Revisedbodyimpedancemodel,Voltmeter,0.22,0.022,u,F,R3,C2,Frequencysensitivenetworkforreaction,(a)Inputimpedance(UL101):,RevisedMeasurementInstrumentforReaction,UL101-1992,IEC60990-1999,Z=V1/I1(20Hz-1MHz),Rmsreading(UL101),Peakreading(IEC60990),(b)Transferimpedance(UL101):,Z=V3/I1,(d)Meterindication(IIndicated):,=V3/R2=V3/500,(weightedmA-IEC60990;MIU-ANSIC101),(c)InputvoltagepermAindication(IEC60990):,V1/IIndicated(mA),Frequencysensitivenetworkforreaction,R3,R1,C1,Bodyimpedancemodel,0.22,uF,IEC60990-1999,MeasurementInstrumentforLet-Go,FrequencysensitivenetworkforLet-Go,M,0.0062,0.0091,uF,R4,C2,C3,V3,V1,Voltmeter,Peakreading(IEC60990),(a)Outputvoltagetoinputvoltageratio:,V3/V1(20Hz-1MHz),(c)Inputvoltagepermilliampereindication:,(b)Meterindication(scale):,IIndicated=V3(peak)/500,WeightedmA,V1/Iindicated(mA),MeasurementInstrumentforBurns,R1,C1,0.22,M,(truermsresponding),Bodyimpedancemodel,Touch(Leakage)CurrentTopicsDefinitions(UL101,IEC60990)TouchcurrentpathsPhysiologicaleffectsoftouchcurrent(electricshock)Bodyimpedancemodelsand“safe”voltagelimitsTouch(Leakage)CurrentTest,Touchcurrentinstruments(meters)Measurementcircuitsandprocedures,MeasurementInstrument,EUT(EquipmentUnderTest),Powerconnections,Touch(Leakage)CurrentTestMeasurementCircuitComponents,Powersupply,Switchingnetwork,MeasurementEquipmentConnections,120V,GNDOPEN,A,A,B,B,S2,S1,2-pole,2-wire,ApplicableEUTPlugConfigurations,2-pole,3-wire,PowerSupply,L,N,Polarityreversingswitch,Groundedconductorswitch,Connectiontogroundedsupplyconductor,MeasurementCircuitfor120VoltEquipment,UL101,SwitchingNetwork,120V,A,A,B,B,S2,S1,2-pole,2-wire,ApplicableEUTPlugConfigurations,2-pole,3-wire,S3,Optionaltransformer,1.6xrmsvalue(rmsmeters),0,0,5,10,15,20,25,30,4.21,7.1,COMPOSITECURRENT(AC+DC),DCCURRENT-mA,AC+DC=,-ln(DC/30),.68,FOR4.21DC30,+DC,5,10,15,20,25,30,mApeak,t,i,t,i,V10-018,Let-GoLimitsforCombina