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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!& x& H( k% j& l1 i* C
7 i5 A! k9 X% F6 Y m# F. H
28.1
H9 |, v/ R% |2 Q( ]! `1 F, Q3 [For conductive patterns on printed circuit boards, except at their edges, the values in the
, d& Z Y; b/ o/ _- _0 q$ W" etable between parts of different potential may be reduced, as long as the peak value of the9 N7 B: i0 n9 M1 h+ G
voltage stress does not exceed:; k& s. R3 D/ F2 _$ b" P
– 150 V per mm with a minimum distance of 0,2 mm, if protected against the deposition of dirt;
0 O' E8 D ?5 `( d' a– 100 V per mm with a minimum distance of 0,5 mm, if not protected against the deposition of& |! l/ i; o+ l6 [& |4 P" R
dirt.' I/ _3 _! o- [ y5 _5 X( q( S: O: I8 z
When the limits mentioned above lead to higher values than those of the table, the values of2 ]' N4 H! y3 q/ n8 X" ^' ?, q- u
the table apply., v0 o* r, G2 ]- n
For peak voltages exceeding 50 V, the reduced creepage distances only apply if the Proof
. T* ^% V. S; A) p# ?+ D" ~Tracking Index (PTI) of the printed circuit board, measured as in Annex G, is greater than
. n8 n. ?' M& z1 ?! a175.
- @% `/ v( _. `1 {) |These distances may be reduced further, provided that the tool complies with the; p$ r$ @- n5 b- N _
requirements of Clause 18 when the distances are short-circuited in turn.
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! \" U5 v$ v2 B7 V* ?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.
' E. N: _+ s: m- z' R- f! k ——若是防尘物沉积的,为150V/mm,但最小距离为0.2mm.5 ?6 I: J" W2 H* m% ?
——若不是防尘物沉积的,为100V/mm,但最小距离为0.5mm.
7 B* ^3 M- P1 J4 H. y 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.- Y" b$ u2 `6 }& R' w
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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