关于爬电距离和空气间隙的标准剖析.ppt

29.3.2 Material requirement for reinforced insulation (2) Live Part 1st layer insulation 2nd layer insulation 3rd layer insulation Any two layers together should withstands the electric strength test for reinforced insulation 1mm Case 1 Clearance Creepage distance = 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 80°and with a width greater than 1mm Case 4 Clearance Creepage distance Case 5 Clearance Creepage distance 1mm 1mm Rated voltage V Rated impulse voltage V Overvoltage category I II III =50 330 500 800 50 and =150 800 1500 2500 150 and =300 1500 2500 4000 Clause 29Clearances, Creepage distances and solid insulation爬电距离、电气间隙和绝缘穿通距离 (Table 1) 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 =50 330 500 800 150 and =150 800 1500 2500 150 and =300 1500 2500 4000 220 – 240V Using category II The rated impulse voltage was 2500V 29.1.1 clearances of basic insulation 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 The minimum clearances of basic insulation was 1.5mm Special components for basic insulation The terminals of tubular sheathed heating elements counted 1mm, if the microenvironment is pollution degree 1. 1mm Tubular s