|
29.1 Clearances shall not be less than the values specified in Table 16, taking into
7 F! z0 L2 ]9 r, T+ Faccount the rated impulse voltage for the overvoltage categories of Table 15, unless, for& M* H+ a. d$ c5 f1 b# _
basic insulation and functional insulation, they comply with the impulse voltage test of
) }( g; m9 D8 S1 H. fClause 14. However, if the construction is such that the distances could be affected by wear,% w& x# ^" @ {, D3 d
by distortion, by movement of the parts or during assembly, the clearances for rated impulse
0 L) ^6 l. Z$ ?9 w5 g* r: m, g0 g5 n& s$ @voltages of 1 500 V and above are increased by 0,5 mm and the impulse voltage test is not
% M7 ]8 B4 J* R$ w* N) _applicable.% e2 V7 B/ {( D7 n3 W
The impulse voltage test is not applicable when the microenvironment is pollution degree 3 or
4 c+ p% F( m4 y5 bfor basic insulation of class 0 appliances and class 0I appliances."
) v. j( n7 ^( G- V( l P+ f: Z! s2 i ?' d( q5 l
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
+ E0 ~- X1 o' \' {8 m) H
: |4 i+ ~6 R D4 ~- C) x污染等级, 一般暴露在外面, 有电机。 的部位一般判3类9 }! _8 W$ Y2 ]7 t- ~: M" u; v
有一定的密封, 一般不会有灰尘进去就可以判2类。
! r) V, f9 i& Z) V0 m+ z3 |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。 |
|