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标题: DSH 717 Creepage and clearance determination, groove, recess, corner, bridging o [打印本页]
作者: 小米    时间: 2012-11-8 21:02
标题: DSH 717 Creepage and clearance determination, groove, recess, corner, bridging o
本帖最后由 小米 于 2012-11-8 21:04 编辑 # T5 k, x; C& c8 S, c! P
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DSH 717/ l! W& }* o5 [% |) l7 v
Creepage and clearance determination, groove, recess, corner, bridging of distance X
6 t) \& F1 H4 c) t8 n" B		4.2, 6.2
+ s0 c3 x" j2 ]" T		60664-1(ed.1.2) & 60065-1(ed.2) & All equipment standards based on these6 F- |6 \8 h: ?3 u' F. `3 P; @4 T
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Standard(s): No. Year
  j% N- x3 ^9 `! kIEC 60664-1/2002 ed1.2
" V, |" r" |& a- c5 O7 x' w+ uIEC 60664-1/2007 ed2.0
* K) k7 j# x3 M" fAll equipment standards3 N! z5 {% ]3 t. _
based on these2 F1 X/ @% U* U2 y; |% Q: u0 o
DSH
+ G  @5 g- U3 _. L! R6 m( P0717
/ H" Z( `- `, b8 A2 f2008
! v3 q3 Y; Z8 j" y0 e0 l8 mCategories:' \9 x8 u' M! e4 K
Various, General
3 }+ E( m, ^( k6 vSubclause(s):
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6.2- U' Y# F2 L# u8 w! H  T6 f: o; T; @
Developed by:0 h7 W; d( G5 U) Y* m/ }5 ?
WG2 - WG4) _" n; O0 t$ L
Subject:
! Y( T, O3 Z! k& p$ X- M: w, ?+ ECreepage and clearance
" R8 |/ G# g% @$ H4 Sdetermination, groove,& q& e( k7 {& K" q
recess, corner, bridging
; u$ P( S! j4 z9 `& ]1 Z. yof distance X, o3 ^* I" w0 g' `8 q, l) R0 \
Key words:# a9 x. K/ l' l* j9 ], P, Y' Q! p
- Creepage. D1 i/ b' d0 [+ C4 Z( v) t4 x" d
- Clearance
1 }' A2 `4 f! k9 F' l) n- Groove
0 V7 s& Y9 W. i' N- Recess* e! E' T" Z" i) k& [1 h3 X
- Corner
# u  S+ ]- I: d7 e* e! A- Bridging of distance
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Decision approved at the! `( B# Q/ z/ r6 H
2009 CTL Plenary  y" U; i& P3 l" w$ B, u2 r3 ^: b# Y
Meeting
6 v- E7 [9 C0 H3 wQuestions:' H! D# [- A7 q+ z* D' e/ G; o  \
1) How shall the examples given in IEC 60664 be interpreted for intermediate situations?
/ X$ Z- |+ @* c9 I2) How shall the example given below be judged correctly, based on the examples given in" O. w/ o# K/ T, j& O
IEC 60664-1 and based on the assumption that X = 1 mm?
' N: A' I% }6 z+ C4 ^" k9 ?0,8mm
* V' L! Z; l1 y0 ~# G) k: c, F4 {3 q2 mm: `. F* s9 r4 U! A& k( O  h
PCB
5 Z3 S! L- T5 L# f. @7 i& p* rPCB-Track (ending on the+ J/ g( ]+ ]5 x& }
edge of the cut-out! t( R/ k7 h& s6 h
3) When shall the sentence:
5 n& u3 y6 X3 S& l6 O“If the associated clearance is less than 3 mm, the minimum dimension X may be reduced to( u" ~& A* r( K7 k! t# N
one third of this clearance.” be applied?
( s7 N( h6 n5 w+ tDoes this sentence refer to the actual clearance measured or to the minimum clearance
9 A2 y, |) K: hrequired?
0 p4 z0 h4 S7 ADecisions:) s8 R+ s2 m' H) X% K9 K
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An intermediate situation not covered directly by the Standard shall be determined by1 d; j6 p% K; C. M# {( k1 y
considering it as an extension of the most appropriate example from the Standard. An example
1 e. S# \3 o3 Q9 ?; mof the methodology is given in the Explanatory Notes to Question 2."! T; q% }: q9 _: K
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The example shall be judged without any bridging of the corner in the cut-out# m: B7 x7 S6 {+ b3 x& y  f  w
 creepage = 2,8 mm, no shortcut applicable." q" r# G) ^* r% ]
Ad 3)
0 w' H& Z: O2 R5 W% y0 f8 fThe sentence shall always be applied whenever the required clearance is less than
* E8 |# B5 U- B+ C3 mm and the allowed reduction of the minimum dimension X shall be referred to 1/3 of the' k8 G5 k% C! E; V' V' t
required minimum clearance.
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