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楼主 |
发表于 2011-3-10 16:37
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那看这一段标准上的列子IEC61131-2
: E" n3 h y7 i# u; F( {2 N' ZZone 1: At the field wiring terminals the 1,6 mm from Table 51 dominates the 1,64 mm/ j, `7 f2 F2 T. Y6 d
creepage distance from Table 54. Therefore, a minimum of 1,6 mm clearance and creepage
% T* H! Q; T$ [' Jdistance shall be maintained. Beyond field wiring terminals, basic clearances shall be 1,50
( s: x: ~! a: m# n& n: `: Imm or greater, according to Table 49, and creepage distances shall be 1,64 mm or greater,
8 M- h; y, @/ N6 raccording to Table 54.
( z) c+ J) }; g) h( J: D. D' R/ SZone 2: On a printed circuit board a minimum basic clearance of 2,25 mm shall be maintained& ^' M& } z: S+ }* }
according to Table 49 for the working voltage of 450 V and a creepage of 2,85 mm from
* ?; o: r S* R0 {Table 56 because of the 1 600 V recurring peak。
( s/ E9 @8 c- {0 s9 A" q5 uAt the isolation boundary to the SELV circuit the 2,3 mm clearance from Table 50 dominates) w: e: F6 j5 }2 F3 @+ v
the 1,73 mm creepage calculated by multiplying the interpolated value of 0,87 from Table 55
5 d) v5 I6 d/ ]. e5 r+ zby 2 according to 11.4.4 for double insulation. Therefore, a 2,3 mm minimum clearance and
5 p, A" ]+ S6 V) k/ lcreepage distance shall be maintained.$ Z1 J& @ \7 f. u3 P- {3 [
最后在取SELV的爬电距离时,选择了系统电压值。 |
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