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29.1 Clearances shall not be less than the values specified in Table 16, taking into: `8 y4 `# G: c% H. P
account the rated impulse voltage for the overvoltage categories of Table 15, unless, for6 n) F3 p$ u$ f( G3 N
basic insulation and functional insulation, they comply with the impulse voltage test of
" v: J' G- R- C( A) S7 A8 JClause 14. However, if the construction is such that the distances could be affected by wear,+ F5 O0 B1 W& O7 I2 ?/ O: A
by distortion, by movement of the parts or during assembly, the clearances for rated impulse
A8 s, g/ }. Q1 Fvoltages of 1 500 V and above are increased by 0,5 mm and the impulse voltage test is not
9 o7 I% a; ?3 m' E; sapplicable.8 s$ o( n k7 n+ e Q
The impulse voltage test is not applicable when the microenvironment is pollution degree 3 or
) M" b9 _1 z8 U' yfor basic insulation of class 0 appliances and class 0I appliances."
! p, l, C3 S' J t7 _9 ~3 m) \* f, U
14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. i; h! y1 }! X
: T( w& M1 t e d
污染等级, 一般暴露在外面, 有电机。 的部位一般判3类! E" J# b6 `$ x1 o% R2 x# h- o
有一定的密封, 一般不会有灰尘进去就可以判2类。
) ~' b' i2 s$ n* N5 p1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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