|
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!+ C& t' ?8 L; t" c( W5 s6 W" }7 }
; B4 a( c3 U0 `. v- r, X
28.10 [/ J5 H, P& I& Q) A, `6 g
For conductive patterns on printed circuit boards, except at their edges, the values in the- O) J& @3 _! u
table between parts of different potential may be reduced, as long as the peak value of the& `0 a! [- A5 j4 w1 U6 q
voltage stress does not exceed:
* m# q" S+ R+ N- n– 150 V per mm with a minimum distance of 0,2 mm, if protected against the deposition of dirt;9 N6 i% L5 M6 m
– 100 V per mm with a minimum distance of 0,5 mm, if not protected against the deposition of
: U# Y# {9 `. m- u/ w8 q" pdirt.
: e' P+ d) |: S- u7 xWhen the limits mentioned above lead to higher values than those of the table, the values of
" O$ b9 h; t' Z7 G) I5 p/ Othe table apply.# a# W8 B' t& Q. x+ T' Y
For peak voltages exceeding 50 V, the reduced creepage distances only apply if the Proof
* I3 z. C7 _7 ~, ]' t$ FTracking Index (PTI) of the printed circuit board, measured as in Annex G, is greater than7 q V3 P' Z7 U1 X D
175.
; |$ E* b7 [( u1 g* U# g$ xThese distances may be reduced further, provided that the tool complies with the6 o. m# w. |- ^
requirements of Clause 18 when the distances are short-circuited in turn.
: O& M& }( n( [4 @5 K
% {2 ] t3 u$ h5 ^6 T' w: n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.
9 G6 A' f: P& p, ?, x% x ——若是防尘物沉积的,为150V/mm,但最小距离为0.2mm.
% {% [: T" c9 N/ P V% D ——若不是防尘物沉积的,为100V/mm,但最小距离为0.5mm.
, n6 U$ ~2 w' s 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.
2 V5 @7 I4 p# m) D ]% k 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. |
|