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Question9 B2 m) y0 ~$ s
1) In case of components mounted on a printed wiring board (PWB) and placed across
8 ?- c5 x8 H- @3 F+ w1 J- ~# D(bridging) insulating distances on the PWB (e.g. providing basic or even reinforced insulation),% T: N0 |( a; x# m2 i' s' h
how to deal with the different distance requirements for distances on the printed wiring4 o9 m- \" \& i0 t: n) M, v8 D
material and for distances on other plastics e.g. the housing material of the component$ L8 I; J" ]3 T4 G! }+ q- ^
(depending on the applicable material group)?3 ^8 }9 i8 H$ y+ u7 G3 E
2) In case of components mounted on a printed wiring board (PWB) and placed across% M" e, Z- ^! ^4 v9 [
insulating distances on the PWB (e.g. providing basic or even reinforced insulation), how to. R& ]- W. @1 `- d& S& n
deal with the different distance requirements, if the material group for PWB and for the y1 d* O, D0 X4 N7 Z4 C
components placed on it is not the same (e.g. PWB of material group I and relay base of7 W8 l& V3 I; Z! i- M i# `% C
material group IIIa)?
$ O6 I7 v5 O2 D! G4 _% ADecision
4 N6 e2 {' R+ U0 {2 Z3 x- S8 f1) The defined reduced values for the required creepage distances relevant to printed wiring5 |8 X* n7 Y$ W. d/ X
material in micro-environment of pollution degrees 1 and 2 may only be applied when there
& D, \& D% ~! ^8 s' Sare no components bridging the investigated insulation. If components are bridging insulating: v; ^2 m; S8 C1 V0 T
distances on the PWB, the creepage distance requirements relating to the (component)- B( L: u$ g( D' c4 a) Z0 y
material representing the worst case has to be applied for the PWB also.: m1 ^9 U, L; k1 c/ p+ t: i4 ]
2) In case of different material groups for the PWB and the components, again the requirement' z! f6 X9 ~' q; T' g
relating to the material representing the worst case has to be used.% {; b* W' g9 _+ u/ n
Remark: A component is considered to bridge insulation on the PWB, if the surface of the2 Q8 R) d* M! x; h5 I
component is located at a distance less than the value “X” (e.g. according to IEC 60664 series)$ m6 N6 D* Y$ i, V
from the isolating PWB surface. See also enclosed drawing.
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发表于 2017-1-7 22:05
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