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那看这一段标准上的列子IEC61131-2! P& t0 R8 w& P6 W
Zone 1: At the field wiring terminals the 1,6 mm from Table 51 dominates the 1,64 mm
9 j% {! X8 [$ _creepage distance from Table 54. Therefore, a minimum of 1,6 mm clearance and creepage
5 v4 V2 @9 g# l0 Z# `0 j- fdistance shall be maintained. Beyond field wiring terminals, basic clearances shall be 1,50
" O9 _; ~8 h' x& o+ emm or greater, according to Table 49, and creepage distances shall be 1,64 mm or greater,
2 l: y5 H- j: s1 Taccording to Table 54.
- d! U: b, \( b8 H9 _Zone 2: On a printed circuit board a minimum basic clearance of 2,25 mm shall be maintained* `/ k) `; V6 J7 q: s
according to Table 49 for the working voltage of 450 V and a creepage of 2,85 mm from
9 p0 V% _& j; y5 `' R) ?Table 56 because of the 1 600 V recurring peak。
9 {3 i# G3 Z8 ]2 F) M% c+ ?At the isolation boundary to the SELV circuit the 2,3 mm clearance from Table 50 dominates P7 m9 x; D' q* a" N! j/ k& \
the 1,73 mm creepage calculated by multiplying the interpolated value of 0,87 from Table 554 H6 c( s7 s: M8 `$ M
by 2 according to 11.4.4 for double insulation. Therefore, a 2,3 mm minimum clearance and
! |) P/ g4 Z5 f6 F+ tcreepage distance shall be maintained.
+ r/ z& C/ w. n' l% p8 g最后在取SELV的爬电距离时,选择了系统电压值。 |
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