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29.1 Clearances shall not be less than the values specified in Table 16, taking into
; [+ J5 i! s. m$ O& Baccount the rated impulse voltage for the overvoltage categories of Table 15, unless, for% ~3 q" e- ?; X9 L+ _8 s- E% X! C
basic insulation and functional insulation, they comply with the impulse voltage test of p1 X* O4 _0 ]$ G
Clause 14. However, if the construction is such that the distances could be affected by wear," T) a5 G/ D! ?( r
by distortion, by movement of the parts or during assembly, the clearances for rated impulse* ?: p( k- I0 X. M+ p- p; L
voltages of 1 500 V and above are increased by 0,5 mm and the impulse voltage test is not$ v1 T. g/ ]! h r
applicable.
& \, e; K; j8 sThe impulse voltage test is not applicable when the microenvironment is pollution degree 3 or
' u# C4 `9 u# d4 L% w U8 C( \6 i% Bfor basic insulation of class 0 appliances and class 0I appliances."5 ^2 M7 E& j5 J
5 S, c& Y8 O B& l$ z& U14章对功能绝缘和基本绝缘适用,电气间隙过不了,一般认证机构不会去做14章的。直接就failed了) o K6 T2 w& I7 q
9 ?/ H' ^4 v2 t污染等级, 一般暴露在外面, 有电机。 的部位一般判3类
( i# r7 [ F7 v' @有一定的密封, 一般不会有灰尘进去就可以判2类。$ z( T5 P% W: i
1类一般很少判, 除非象继电器一样完全密封的才看作1类。 |
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