|
楼主 |
发表于 2011-3-10 16:37
|
显示全部楼层
那看这一段标准上的列子IEC61131-2$ J7 K2 u5 O0 G0 a. e H- H& @, H
Zone 1: At the field wiring terminals the 1,6 mm from Table 51 dominates the 1,64 mm
3 U3 \& J O0 h9 ~) ~: C3 Gcreepage distance from Table 54. Therefore, a minimum of 1,6 mm clearance and creepage9 ]# S" l8 }* _) H) z
distance shall be maintained. Beyond field wiring terminals, basic clearances shall be 1,50+ M3 U- C2 A) B& ?
mm or greater, according to Table 49, and creepage distances shall be 1,64 mm or greater,2 h" y: Z# V# h0 L. a
according to Table 54.
: s$ U8 h8 d3 u1 w0 I) y" fZone 2: On a printed circuit board a minimum basic clearance of 2,25 mm shall be maintained
3 Q" ^9 z3 s4 qaccording to Table 49 for the working voltage of 450 V and a creepage of 2,85 mm from
( Z5 e( R( N! {3 OTable 56 because of the 1 600 V recurring peak。
' P0 }! S" u7 E$ o2 _, HAt the isolation boundary to the SELV circuit the 2,3 mm clearance from Table 50 dominates+ Y* Q% }+ c: `4 ]
the 1,73 mm creepage calculated by multiplying the interpolated value of 0,87 from Table 55
7 f9 h* J/ p! u p# Pby 2 according to 11.4.4 for double insulation. Therefore, a 2,3 mm minimum clearance and. f: o. A) @% O! D3 q
creepage distance shall be maintained., f9 t* r8 ~. E" J# ?
最后在取SELV的爬电距离时,选择了系统电压值。 |
|