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关于这个问题,我觉得这个观点不错:
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& r1 q9 i. [% A* b! T以下标准性文字均引用于IEC 60335-1-2006
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T$ o6 a" |% b& A0 D! ~- e功能性绝缘的定义:
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functional insulation3 g+ a+ K9 O" a9 I G
insulation between conductive parts of different potential which is necessary only for the proper functioning of the appliance。 {% {1 z' [& n' `2 [' w: a3 O F
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功能性绝缘的电气间隙的要求:9 d+ Y: H/ T4 H6 c5 b0 u3 E
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$ [4 _& h; k3 p- fFor functional insulation, the values of table 16 are applicable. However, clearances are not specified if the appliance complies with clause 19 with the functional insulation short-circuited. Lacquered conductors of windings are considered to be bare conductors. However, clearances at crossover points are not measured.
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5 ]& M/ C/ b1 }. q) {- x, V) A9 @8 P看蓝色字体部分,只要在短路时,能满足clause 19的要求,可不要求functional insulation 的电气间隙。6 W# p- Q8 l5 E* p+ N
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看红色字体部分,漆包线被视为“裸露导体”。也就是在本标准中,漆包膜不被视为功能性绝缘。这个前提很重要,这意味着绕组间不必进行“短路测试”。0 H) g( Y1 o/ H8 V, C0 Y0 X$ d
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5 _, y+ x$ }' m, D: M* F) C. t9 \功能性绝缘的爬电距离的要求:
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Creepage distances of functional insulation shall be not less than those specified in table 18. However, creepage distances may be reduced if the appliance complies with clause 19 with the functional insulation short-circuited.
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! ]/ O' H9 B8 G7 @6 S看蓝色字体部分,只要在短路时,能满足clause 19的要求,functional insulation 的爬电距离的要求可减小。标准并没有说可以减小到多少,这就意味着,只要 functional insulation 能在短路时满足clause 19的要求即可满足爬电距离的要求。
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结论:从标准的理解来看,functional insulation 仅为设备正常工作所需的绝缘,如果functional insulation 能在短路时满足 Clause 19 的要求,可不要求其电气间隙和爬电距离。 ' g. S- }' B' m, q) R& {
8 c* g( v- I t9 v实际上,我也是这么处理的。只要在检查、评估中发现functional insulation 的距离(cl & cr)很小,那么就用短路测试来检验,如果满足不了短路测试,那么我就要求其CL & CR。
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