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有没有人知道如下条款中说提到的电压梯度的峰值如何检测?有没有实例说明怎么将这个条款应用到线路板上呢?谢谢!
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28.1$ K0 v7 V: C1 F6 i# r, c
For conductive patterns on printed circuit boards, except at their edges, the values in the
+ d( ?+ t) f2 g/ u+ Atable between parts of different potential may be reduced, as long as the peak value of the, H8 T+ l I$ L8 ~0 o/ B. j$ C4 z
voltage stress does not exceed:( |- l0 C: ^8 e9 c5 f
– 150 V per mm with a minimum distance of 0,2 mm, if protected against the deposition of dirt;
) G* ^" ?' Z1 d. Y, h% m |8 C4 a– 100 V per mm with a minimum distance of 0,5 mm, if not protected against the deposition of5 s( n0 O- ]% Q I. e
dirt.: c) k3 X) Z4 H8 ?' w
When the limits mentioned above lead to higher values than those of the table, the values of" o' K! f1 L/ F! D
the table apply.
4 j, y- V- c- Z/ Q2 S, R7 {- {For peak voltages exceeding 50 V, the reduced creepage distances only apply if the Proof' `8 v O4 l) E' {
Tracking Index (PTI) of the printed circuit board, measured as in Annex G, is greater than( A8 e4 _8 I; p0 p: O/ C" z( p% E7 d
175.1 B% B. p% ?' j
These distances may be reduced further, provided that the tool complies with the
: Q6 {: }) Q( E! N2 p" g# T+ W% Irequirements of Clause 18 when the distances are short-circuited in turn.
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0 E3 y+ u# n5 A( U; b对印刷电路板上的导电图形,其边棱除外,只要电压梯度的峰值没有超过下述值,表中关于不同极性部件间的值可以减小.
2 R3 C4 z. n7 _# X' x; l: r$ W ——若是防尘物沉积的,为150V/mm,但最小距离为0.2mm.8 V$ t, c7 W" b% X7 K
——若不是防尘物沉积的,为100V/mm,但最小距离为0.5mm.* C# K* m& q! K$ l; k1 I
对峰值电压超过150V的情况,只有印刷电路板的耐漏电起痕指数(PTI)按照附录G进行测量时超过175,减小的爬电距离规定才适用.$ j* }' l' ~- u6 q( k( X- c n0 s: p
只要当这些距离轮流短路时,器具符合19章的要求,这些距离可以进一步的减小. |
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