|
|
Question
! J& m y, y8 }$ O1) In case of components mounted on a printed wiring board (PWB) and placed across8 N. T: k# M; F/ }; ]1 f$ a
(bridging) insulating distances on the PWB (e.g. providing basic or even reinforced insulation),
! X( I0 q% ^, l( ^how to deal with the different distance requirements for distances on the printed wiring" F' Z! _6 @0 D1 ~0 H8 ^
material and for distances on other plastics e.g. the housing material of the component
2 q" ~; i' r' f9 X(depending on the applicable material group)?3 l5 }; @, m7 j$ O) E4 k
2) In case of components mounted on a printed wiring board (PWB) and placed across
% f% R9 l v/ W3 x) i- Finsulating distances on the PWB (e.g. providing basic or even reinforced insulation), how to9 P& b& p- {- l/ b
deal with the different distance requirements, if the material group for PWB and for the& b7 v/ y4 I# F8 B/ q! l4 p
components placed on it is not the same (e.g. PWB of material group I and relay base of
T2 K- k0 u# ]9 T4 M3 T* E# s3 s) Qmaterial group IIIa)?; U) ?& Z" [3 l) \
Decision
# D+ H2 @2 O" @/ f% ?8 b$ A1) The defined reduced values for the required creepage distances relevant to printed wiring
" Z: s; j& d2 xmaterial in micro-environment of pollution degrees 1 and 2 may only be applied when there) Z U$ C/ ]/ N, P
are no components bridging the investigated insulation. If components are bridging insulating. X" Q/ ~. Z0 x+ P6 d# t# k
distances on the PWB, the creepage distance requirements relating to the (component)7 S* T4 B! X0 S' s& b
material representing the worst case has to be applied for the PWB also.' {1 |; }6 z* k, `. Y
2) In case of different material groups for the PWB and the components, again the requirement
/ f# @, w3 E( E$ Frelating to the material representing the worst case has to be used.1 A" l8 T% M' y/ p, q+ P
Remark: A component is considered to bridge insulation on the PWB, if the surface of the0 Q5 `) \2 ] z0 o' [ i% G! }: N
component is located at a distance less than the value “X” (e.g. according to IEC 60664 series)4 c1 d7 y4 l: D
from the isolating PWB surface. See also enclosed drawing.
3 i0 _$ y) P6 ~$ z
Q9 o! C: t& V& e$ U
! B K# R G; C6 j4 a |
|
/2 
|关于安规|小黑屋|安规QQ群|Archiver|手机版|安规网
( 粤ICP13023453-10 ) 
窥视卡
雷达卡
发表于 2017-1-7 22:05
提升卡
置顶卡
沉默卡
喧嚣卡
变色卡
抢沙发
千斤顶
显身卡
楼主