标题: DSH 2001 [打印本页] 作者: chinatown 时间: 2017-1-7 22:05 标题: DSH 2001 Question + x3 Q) P3 n6 R/ r/ k1 d B9 s1) In case of components mounted on a printed wiring board (PWB) and placed across 9 [; E* N$ \: _, t3 T(bridging) insulating distances on the PWB (e.g. providing basic or even reinforced insulation),: A! s! Y) D' I, d) J9 Y5 l! D
how to deal with the different distance requirements for distances on the printed wiring 5 z% @# R# \0 E3 J( ematerial and for distances on other plastics e.g. the housing material of the component' z+ F+ U/ O. g7 B8 O
(depending on the applicable material group)?, Y5 P' C2 H2 g" |2 Q( g3 X
2) In case of components mounted on a printed wiring board (PWB) and placed across" z, i' k5 d, b7 |0 k! B) S1 ]
insulating distances on the PWB (e.g. providing basic or even reinforced insulation), how to ) `4 Z4 Z* V( Z" J2 e# o; \' a/ fdeal with the different distance requirements, if the material group for PWB and for the 0 }! m: E' c& D5 d: `% Wcomponents placed on it is not the same (e.g. PWB of material group I and relay base of 9 P) ?4 m' x2 g0 _6 A6 W& Hmaterial group IIIa)? * T7 b% ]. x/ \: F' X3 G$ FDecision1 V! M2 O( D7 h) E5 G; Q
1) The defined reduced values for the required creepage distances relevant to printed wiring / Q1 M6 e8 X# Smaterial in micro-environment of pollution degrees 1 and 2 may only be applied when there' r; D9 r N8 b5 s$ E! C# I$ Q
are no components bridging the investigated insulation. If components are bridging insulating- R' n; H4 S# e7 c5 |
distances on the PWB, the creepage distance requirements relating to the (component) * ?3 T4 G$ G! h4 hmaterial representing the worst case has to be applied for the PWB also. # Q5 D O/ Z @# Q/ s: C2) In case of different material groups for the PWB and the components, again the requirement ( o6 o. T. o3 q% M0 s* q% ^# _relating to the material representing the worst case has to be used. 0 m4 Z4 |, M) w1 e! M; pRemark: A component is considered to bridge insulation on the PWB, if the surface of the / a: S o4 d7 _component is located at a distance less than the value “X” (e.g. according to IEC 60664 series)( {) i8 a* F9 Z' T0 ?! v
from the isolating PWB surface. See also enclosed drawing. " x( K' n2 c4 A0 H0 |4 @7 T( y- ]/ U8 |