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* ^3 o9 U% c* N: U. x6 e+ QQuestion:
( \; v K, o- O% w! Z0 CClause 29 indicates that coatings to Annex J can protect the microenvironment and provide basic insulation. Annex J appears to recognize both Type A and Type B coatings.
- P+ ~% g$ }9 O+ V+ Q$ X) xIEC 60664-3: 1992 distinguishes between Type A and Type B coatings.
7 v, ] g' R6 M( u I1- Does type A coatings serve to improve the environments from PD2 to PD1?) p d, y- ^* L d2 d/ k2 h
2- Are creepage distances and clearance requirements applicable between conductors under type B coating?
8 l2 x+ P4 `6 {4 z4 I MDecision:8 t W( T6 y& t! j; ^ P$ H. ^
1- Type A coating according to IEC 60664 allows to improve the environment from Pollution Degree (PD) 3 to 1, in the same way it allows the transition from PD 2 to 1.- G6 w% G5 \. s( [, H8 Y% D( j
2- Type B coatings do not require creepage and clearance distances between tracks covered by this type of coating but for type A coating, distance for PD 1 applies.
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发表于 2012-9-8 20:57
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