关于爬电距离和空气间隙的标准ppt课件.ppt

Clause29Clearances Creepagedistancesandsolidinsulation爬电距离 电气间隙和绝缘穿通距离 Table1 1 Minimumclearance Table2 2 Howtofindtheminimumclearance HouseholdapplianceareinovervoltagecategoryIISelecttheratedvoltageUsingthetable1tofindouttheratedimpulsevoltageAccordingtotable2 theminimumclearancecouldbefoundbyratedimpulsevoltage Theclearancesoffourinsulationtypes BasicinsulationSupplementaryinsulationReinforcedinsulationFunctionalinsulation 3 Theclearanceofbasicinsulation Example1 WaterkettleRating 220 240V50Hz2500 3000W 220 240V UsingcategoryII Theratedimpulsevoltagewas2500V 4 29 1 1clearancesofbasicinsulation Theminimumclearancesofbasicinsulationwas1 5mm 5 Specialcomponentsforbasicinsulation Theterminalsoftubularsheathedheatingelementscounted1mm ifthemicroenvironmentispollutiondegree1 1mm Tubularsheathedheatingelement Pollutiondegree1 6 29 1 2clearanceofsupplementinsulation Theminimumclearanceissameasthebasicinsulation Thedistancebetweenenclosureandinternalwire 7 29 1 3clearanceofreinforcedinsulation Thereinforcedinsulationusingthenextstepforratedimpulsevoltage Betweenterminalandplasticenclosure 8 29 1 4clearanceoffunctionalinsulation Betweenterminals Thefunctionalinsulationisbetweenlivepartsofdifferentpotential 9 PTCHeatingelement Hairstraighter PTCheater Hairstraighterassembly 10 DifferenttypesofPTCHeatingelements 11 InternalconstructionofPTCheatingelement TheclearancebetweensurfacesofPTCheatingelementsmaybereducedto1mm Theclearance 1mm Kaptonfilm PTCheatingplate Electrodeplate 12 29 2creepagedistances Step1 Tofindoutthepollutiondegree Pollutiondegree2appliesunlessPrecautionshavebeentakentoprotecttheinsulation inwhichcasepollution1appliesTheinsulationissubjectedtoconductivepollution inwhichcasepollutiondegree3appliesNote Thepollutiondegreeshouldneedrefertopart2 13 Pollutiondegreeclassification 14 Trackingindex CTI valuesMaterialgroupI 600 CTIMaterialgroupII 400 CTIMaterialgroupIIIa 175 CTI 400MaterialgroupIIIb 100 CTI 175 Step2 Tofindoutthematerialgroup Trackingindextester 15 Trackingindex CTI values 16 Minimumcreepagedistancesforbasicinsulation 17 Thecreepageofbasicinsulation Example1 WaterkettleRating 220 240V50Hz2500 3000W Pollutiondegree3 refertostandard60335 2 15 Themicroenvironmentispollutiondegree3iftheinsulationcanbepollutedbycondensationfromsteamproducedduringnormaluseofappliance AssumethematerialgroupisIII thetightengrade Workingvoltageisbetween 125and 250 18 Thecreepageofbasicinsulation 19 Minimumcreepagedistancesforfunctionalinsulation 20 SummaryofMinimumcreepagedistances 21 29 2 1creepageforbasicinsulationLacqueredconductorsofwindings 1 5mm Creepagedistanceofwindingneednotbegreaterthantheassociatedclearancespecifiedintable16 22 Clause29 2 2 Asperclause29 2 2 thecreepagedistanceofsupplementaryinsulationshallnotlessthanand2 5mm Theinternalwireofmicro switchwasnotsecurelyfixedthatitwaspossibletobetouchedbytestfingerwith2Nforce Thecreepagedistanceweremeasuredas0mm Internalwireshallbeaccess 23 Clause29 2 3 Thecreepagedistancesofreinforcedinsulationshallnotlessthan8mm Asresult thecreepagedistancewasmeasured7 5mmbetweenleadsofneonlampandthelampcoverjoint Leadsofneonlamp Lens Enclosure Leonlampleads 2mm 3mm 2 5m Thecreepagedistances 2 5 2 3 7 5mm 24 29 2 4creepagedistancesoffunctionalinsulation 1 5mm 25 Clause29 2 4 26 PCBTrack AB BA BA 27 29 2 4creepagedistanceforfunctioninsulation Creepagedistancesmaybereducediftheappliancecomplieswithclause19withthefunctionalinsulationshort circuited Forexample Electroniccomponent Electroniccomponent Thetransistorleads limitationofcreepagedistance 28 LivePart Supplementaryinsulation 1mm Basicinsulation 29 3 1Materialthicknessrequirementforsupplementaryinsulation 1 SupplementaryInsulation 29 LivePart Reinforcedinsulation 2mm 29 3 1Materialthicknessrequirementforreinforcedinsulation 1 ReinforcedInsulation 30 LivePart 1stlayerinsulation 2ndlayerinsulation Eachofthelayersshouldwithstandstheelectricstrengthtestforsupplementaryinsulation 29 3 2Materialrequirementforsupplementaryinsulation 2 Basicinsulation 31 29 3 2Materialrequirementforreinforcedinsulation 2 LivePart 1stlayerinsulation 2ndlayerinsulation 3rdlayerinsulation Anytwolayerstogethershouldwithstandstheelectricstrengthtestforreinforcedinsulation 32 1mm Case1 Clearance Creepagedistance 33 1mm Case2 Clearance Creepagedistance