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本帖最后由 小米 于 2012-11-8 21:04 编辑
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; l9 E) O, z/ }+ ?7 T | | DSH 717
+ o+ @: S4 F) V, _ s% W5 @ | Creepage and clearance determination, groove, recess, corner, bridging of distance X3 a, @- d* h( o- S" N! K6 s$ h
| 4.2, 6.2- @( p/ @( |$ k& c2 X
| 60664-1(ed.1.2) & 60065-1(ed.2) & All equipment standards based on these
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Standard(s): No. Year
2 `. d" N& c3 H$ q; x6 q: f AIEC 60664-1/2002 ed1.2
; q. f5 t" A0 n2 WIEC 60664-1/2007 ed2.00 `6 \* ?& p% i; j' {/ }# v$ \
All equipment standards
; w3 {. b. y6 \- ?8 p: Vbased on these) `$ Q: X" U, ?5 G9 j1 e
DSH
8 i& A2 m5 Y- Y" r% Z) S- j/ Y0717. C! L6 P" _+ M, q
2008
% D' u' t0 q. I/ Y1 H4 pCategories:
* Z0 N7 A6 U, ^$ V" gVarious, General! @: G! y! J2 I, e5 c4 f
Subclause(s):6 s0 x5 r& `2 q$ |! S
4.2
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Developed by:
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! G9 f% u- f& n! ?( l. l$ bSubject:( f( H$ ~# N2 | U/ x' C
Creepage and clearance4 I; x/ ~4 a- B. y/ ?! X5 S. k. b
determination, groove,8 u6 ^- X3 e7 L* ?1 l( B7 U
recess, corner, bridging
: S/ G3 ?1 V0 u8 [& dof distance X
, N" B' |) l3 k) c( o" @2 WKey words:7 Z$ W$ o" i: X
- Creepage0 m W+ Q: P9 z
- Clearance& ?/ M+ ]3 i& W. o- h6 l
- Groove
) C2 t) L$ h* [- Recess
( F$ q. x- a0 s" S- Corner
* g* A; O! N( B4 [& E1 t- Bridging of distance
. j$ b+ ?7 C2 b! ^8 p2 s( g2 WX! H0 h: }0 o6 Y" K
Decision approved at the
" ~& F6 M( }- Z/ m2 h$ W _% R2009 CTL Plenary; d( D* B1 k+ f
Meeting* ?: b& v$ ^4 D( m9 B. O+ y
Questions:( H2 s. x5 m6 s& e' P' g; M
1) How shall the examples given in IEC 60664 be interpreted for intermediate situations?
n& u' a7 ^) }# w& t1 |! Z1 Q5 B- r2) How shall the example given below be judged correctly, based on the examples given in7 X6 }. B9 W+ F
IEC 60664-1 and based on the assumption that X = 1 mm?5 U+ B8 c0 |0 y% V% F
0,8mm
b* v( k/ ~. I+ z, D* M! ~2 mm. E* |; @( T0 y7 g6 Y; j
PCB! g! M, g+ T' I. |5 J% n
PCB-Track (ending on the
* `+ F3 Z: H) Z# j& ^6 zedge of the cut-out
) O6 f, F8 r# U6 L3) When shall the sentence:" m. O$ J% t" v( u3 S
“If the associated clearance is less than 3 mm, the minimum dimension X may be reduced to* U' f+ `" o. q$ Y
one third of this clearance.” be applied?6 G5 u" p6 V3 b: d4 w4 F& M
Does this sentence refer to the actual clearance measured or to the minimum clearance
- [# ]3 }- q: Y5 u6 B- H9 s1 C, drequired?
/ p, D) G6 X$ y5 G% x# S4 sDecisions:
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) E( t& }, g4 ]1 ?7 b8 ~2 ZAn intermediate situation not covered directly by the Standard shall be determined by. D2 r) L0 p2 {4 ~7 q# B
considering it as an extension of the most appropriate example from the Standard. An example; x4 t; G( Q# f' Q
of the methodology is given in the Explanatory Notes to Question 2."
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+ `6 h) D& P: C* e/ L5 MThe example shall be judged without any bridging of the corner in the cut-out
% E' d2 g4 S7 B+ V8 K- D creepage = 2,8 mm, no shortcut applicable.
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The sentence shall always be applied whenever the required clearance is less than: l2 u; h4 y1 z1 @) [% f; D
3 mm and the allowed reduction of the minimum dimension X shall be referred to 1/3 of the
/ E! s/ C: \& U/ E2 Brequired minimum clearance.3 p+ g6 R& j' u
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