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那看这一段标准上的列子IEC61131-2
$ ?, F7 g g4 y8 Y) c/ F. CZone 1: At the field wiring terminals the 1,6 mm from Table 51 dominates the 1,64 mm
7 Z2 T7 U; b( vcreepage distance from Table 54. Therefore, a minimum of 1,6 mm clearance and creepage
. ]) t; w1 s; K* R( C/ a4 Mdistance shall be maintained. Beyond field wiring terminals, basic clearances shall be 1,50
+ `' A- r2 v S+ Qmm or greater, according to Table 49, and creepage distances shall be 1,64 mm or greater,
7 p' ^& P: l ?8 paccording to Table 54.* U% o" m( q: i V" {
Zone 2: On a printed circuit board a minimum basic clearance of 2,25 mm shall be maintained
4 w$ @! L: _; {8 Baccording to Table 49 for the working voltage of 450 V and a creepage of 2,85 mm from
( L) o0 p* |6 r$ T' }Table 56 because of the 1 600 V recurring peak。
5 Y3 n! s4 A* @) \/ DAt the isolation boundary to the SELV circuit the 2,3 mm clearance from Table 50 dominates
% H( T& W1 y& Q( tthe 1,73 mm creepage calculated by multiplying the interpolated value of 0,87 from Table 55
* N% i3 D8 W, ?" V& ]by 2 according to 11.4.4 for double insulation. Therefore, a 2,3 mm minimum clearance and) R; g7 d4 G9 C0 L7 }: Q. W3 n, j
creepage distance shall be maintained.
1 B5 q& Y% W4 ~1 m) {最后在取SELV的爬电距离时,选择了系统电压值。 |
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