关于爬电距离和空气间隙的标准.ppt

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,关于爬电距离和空气间隙的标准,Minimum clearance(Table 2),Rated impulse voltage,V,Minimum clearance,mm,330,0.5,500,0.5,800,0.5,1500,0.5,2500,1.5,4000,3.0,6000,5.5,8000,8.0,1000,11.0,How 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 voltage,The clearances of four insulation types:,Basic insulation,Supplementary insulation,Reinforced insulation,Functional insulation,The clearance of basic insulation,Example 1:Water kettle,Rating :220 240V 50Hz 2500 3000W,Rated voltage,V,Rated impulse voltage(V),Overvoltage category,I,II,III,150 and 150 and 1mm,Tubular sheathed heating element,Pollution degree 1,29.1.2 clearance of supplement insulation,The minimum clearance is same as the basic insulation,The distance between enclosure and internal wire,29.1.3 clearance of reinforced insulation,The reinforced insulation using the next step for rated impulse voltage.,Between terminal and plastic enclosure,29.1.4 clearance of functional insulation,Between terminals,The functional insulation is between live parts of different potential,PTC Heating element,Hair straighter,PTC heater,Hair straighter assembly,Different types of PTC Heating elements,Internal construction of PTC heating element,The clearance between surfaces of PTC heating elements may be reduced to 1mm,The clearance=1mm,Kapton film,PTC heating plate,Electrode plate,29.2 creepage distances,Step 1(To find out the pollution degree),Pollution degree 2 applies unless,Precautions have been taken to protect the insulation,in which case pollution 1 applies,The insulation is subjected to conductive pollution,in which case pollution degree 3 applies,Note:The pollution degree should need refer to part 2.,Standard,Pollution degree,60335 2 3,II,60335 2 9,III,60335 2 14,III,60335 2 15,III,60335 2 23,II,60335 2 80,III,Pollution degree classification,Tracking index(CTI)values,Material group I:600=CTI,Material group II:400=CTI,Material group III a:175=CTI 400,Material group III b:100=CTI175,Step 2(To find out the material group),Tracking index tester,Tracking index(CTI)values,Minimum creepage distances for basic insulation,Working voltage,V,Creepage distance mm,Pollution degree,1,2,3,Material group,Material group,I,II,III a/b,I,II,III a/b,50 and 125 and 250 and 400 and 500 and 125 and=250,The creepage of basic insulation,Working voltage,V,Creepage distance mm,Pollution degree,1,2,3,Material group,Material group,I,II,III a/b,I,II,III a/b,50 and 125 and 250 and 400 and 500 and=800,1.8,3.2,4.5,6.3,8.0,9.0,10.0,Working voltage,V,Creepage distance mm,Pollution degree,1,2,3,Material group,Material group,I,II,III a/b,I,II,III a/b,50 and 125 and 250 and 400 and 500 and=800,1.8,3.2,4.5,6.3,8.0,9.0,10.0,Minimum creepage distances for functional insulation,Insulation type,Distance,Basic insulation,4,Supplementary insulation,4,Reinforced insulation,8,Functional insulation,3.2,Summary of Minimum creepage distances,29.2.1 creepage for basic insulationLacquered conductors of windings,1.5mm,Creepage distance of winding need not be greater than the associated clearance specified in table 16,Clause 29.2.2,As 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 force.The creepage distance were measured as 0mm,Internal wire shall be access,Clause 29.2.3,The 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 lamp,Lens,Enclosure,Leon lamp leads,2mm,3mm,2.5m,The creepage distances=2.5+2+3,=7.5mm,29.2.4 creepage distances of functional insulation,Creepage distance between,Measured results,Limitation,Switch terminals,1.5mm,2mm,1.5mm,Clause 29.2.4,Distance between,Measured results,Limitation,PCB,Between,Point A and B,Clearance,Creepage,Clearance,Creepage,2.07mm,2.75mm,1.5mm,2.0mm,PCB Track,A B,B A,B A,29.2.4 creepage distance for function insulation,Creepage distances may be reduced if the appliance complies with clause 19 with the functional insulation short-circuited.For example:Electronic component,Electronic component,The transistor leads limitation of creepage distance,Live Part,Supplementary insulation(1mm),Basic insulation,29.3.1 Material thickness requirement for supplementary insulation(1),Supplementary Insulation,Live Part,Reinforced insulation(2mm),29.3.1 Material thickness requirement for reinforced insulation(1),Reinforced Insulation,Live Part,1,st,layer insulation,2,nd,layer insulation,Each of the layers should withstands the electric strength test for supplementary insulation,29.3.2 Material requirement for supplementary insulation(2),Basic insulation,29.3.2 Material requirement for reinforced insulation(2),Live Part,1,st,layer insulation,2,nd,layer insulation,3,rd,layer insulation,Any two layers together should withstands the electric strength test for reinforced insulation,=1mm,Case 2,Clearance,Creepage distance,1mm,Case 3,Clearance,Creepage distance,Path under consideration includes a V shaped groove with internal angle of less than 80and with a width greater than 1mm,Case 4,Clearance,Creepage distance,Case 5,Clearance,Creepage distance,1mm,