关于爬电距离和空气间隙的标准

1、整理课件1Rated voltageVRated impulse voltageVOvervoltage categoryIIIIII50 and 150 and =300150025004000Clause 29Clearances, Creepage distances and solid insulation爬电距离、电气间隙和绝缘穿通距离 (Table 1)整理课件2Minimum clearance (Table 2)Rated impulse voltageVMinimum clearancemm3300.55000.58000.515000.525001.540003.06000

2、5.580008.0100011.0整理课件3How to find the minimum clearance Household appliance are in overvoltage category II Select the rated voltage Using the table 1 to find out the rated impulse voltage According to table 2, the minimum clearance could be found by rated impulse voltageThe clearances of four insul

3、ation types:Basic insulationSupplementary insulationReinforced insulationFunctional insulation整理课件4The clearance of basic insulationExample 1: Water kettleRating : 220 240V 50Hz 2500 3000WRated voltageVRated impulse voltage (V)Overvoltage categoryIIIIII150 and 150 and 1mmTubular sheathed heating ele

4、mentPollution degree 1整理课件729.1.2 clearance of supplement insulationThe minimum clearance is same as the basic insulationThe distance between enclosure and internal wire整理课件829.1.3 clearance of reinforced insulationThe reinforced insulation using the next step for rated impulse voltage. Between term

5、inal and plastic enclosure整理课件929.1.4 clearance of functional insulation Between terminalsThe functional insulation is between live parts of different potential整理课件10PTC Heating elementHair straighterPTC heaterHair straighter assembly整理课件11Different types of PTC Heating elements整理课件12Internal constr

6、uction of PTC heating elementThe clearance between surfaces of PTC heating elements may be reduced to 1mmThe clearance =1mmKapton filmPTC heating plateElectrode plate整理课件1329.2 creepage distancesStep 1 (To find out the pollution degree)Pollution degree 2 applies unlessPrecautions have been taken to

7、protect the insulation, in which case pollution 1 appliesThe insulation is subjected to conductive pollution, in which case pollution degree 3 appliesNote: The pollution degree should need refer to part 2. 整理课件14StandardPollution degree60335 2 3II60335 2 9III60335 2 14III60335 2 15 III60335 2 23 II6

8、0335 2 80 IIIPollution degree classification整理课件15Tracking index (CTI) valuesMaterial group I: 600=CTIMaterial group II: 400=CTIMaterial group III a: 175 =CTI 400Material group III b: 100 =CTI175Step 2 (To find out the material group)Tracking index tester整理课件16Tracking index (CTI) values整理课件17Minimu

9、m creepage distances for basic insulationWorking voltageVCreepage distance mmPollution degree123Material groupMaterial groupIIIIII a/bIIIIII a/b50 and 125 and 250 and 400 and 500 and 125 and =250整理课件19The creepage of basic insulationWorking voltageVCreepage distance mmPollution degree123Material gro

10、upMaterial groupIIIIII a/bIIIIII a/b50 and 125 and 250 and 400 and 500 and = 8001.83.24.56.38.09.010.0整理课件20Working voltageVCreepage distance mmPollution degree123Material groupMaterial groupIIIIII a/bIIIIII a/b50 and 125 and 250 and 400 and 500 and = 8001.83.24.56.38.09.010.0Minimum creepage distan

11、ces for functional insulation整理课件21Insulation typeDistanceBasic insulation4Supplementary insulation4Reinforced insulation8Functional insulation3.2Summary of Minimum creepage distances 整理课件2229.2.1 creepage for basic insulationLacquered conductors of windings1.5mmCreepage distance of winding need not

12、 be greater than the associated clearance specified in table 16整理课件23 Clause 29.2.2As per clause 29.2.2, the creepage distance of supplementary insulation shall not less than and 2.5mm.The internal wire of micro-switch was not securely fixed that it was possible to be touched by test finger with 2N

13、force. The creepage distance were measured as 0mmInternal wire shall be access整理课件24Clause 29.2.3The creepage distances of reinforced insulation shall not less than 8mm.As result, the creepage distance was measured 7.5mm between leads of neon lamp and the lamp cover joint. Leads of neon lampLensEncl

14、osureLeon lamp leads2mm3mm2.5mThe creepage distances = 2.5+2+3 = 7.5mm整理课件2529.2.4 creepage distances of functional insulationCreepage distance betweenMeasured resultsLimitationSwitch terminals1.5mm2mm1.5mm整理课件26Clause 29.2.4Distance betweenMeasured resultsLimitationPCBBetween Point A and BClearance

15、CreepageClearanceCreepage2.07mm2.75mm1.5mm2.0mm整理课件27PCB TrackA BB AB A整理课件2829.2.4 creepage distance for function insulationCreepage distances may be reduced if the appliance complies with clause 19 with the functional insulation short-circuited. For example: Electronic component Electronic compone

16、ntThe transistor leads limitation of creepage distance 整理课件29LivePartSupplementaryinsulation(1mm)Basicinsulation29.3.1 Material thickness requirement for supplementary insulation (1)SupplementaryInsulation整理课件30LivePartReinforced insulation (2mm)29.3.1 Material thickness requirement for reinforced i

17、nsulation (1)ReinforcedInsulation整理课件31LivePart1st layer insulation2nd layer insulationEach of the layers should withstands the electric strength test for supplementary insulation 29.3.2 Material requirement for supplementary insulation (2)Basic insulation整理课件3229.3.2 Material requirement for reinforced insulation (2)LivePart1stlayerinsulation2ndlayerinsulation3rdlayerinsulationAnytwolayerstogethershouldwithstandstheelectricstrengthtestforreinforcedinsulation整理课件33