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那看这一段标准上的列子IEC61131-2
. L9 J, Y% n8 g8 mZone 1: At the field wiring terminals the 1,6 mm from Table 51 dominates the 1,64 mm8 H9 t6 D! G( Q3 D
creepage distance from Table 54. Therefore, a minimum of 1,6 mm clearance and creepage
! K) g- Y8 r, k2 Y) i7 i- rdistance shall be maintained. Beyond field wiring terminals, basic clearances shall be 1,50" X7 |9 g7 `( W% C! I
mm or greater, according to Table 49, and creepage distances shall be 1,64 mm or greater,. {/ M" f5 p1 U+ U& \* S
according to Table 54.
/ a7 J* p ^2 P1 N+ D; JZone 2: On a printed circuit board a minimum basic clearance of 2,25 mm shall be maintained
( o! \- `: \" H" v3 ^according to Table 49 for the working voltage of 450 V and a creepage of 2,85 mm from: I! ]6 j e8 [. w, l
Table 56 because of the 1 600 V recurring peak。0 ~4 e# H- K/ q& u( h @
At the isolation boundary to the SELV circuit the 2,3 mm clearance from Table 50 dominates
: L% O( x7 _# l) w( h- T m Ythe 1,73 mm creepage calculated by multiplying the interpolated value of 0,87 from Table 55
' w/ |/ q+ v5 o k1 Xby 2 according to 11.4.4 for double insulation. Therefore, a 2,3 mm minimum clearance and
8 a6 j8 u& C! Z7 x( J, acreepage distance shall be maintained.
* U/ i B5 @& @最后在取SELV的爬电距离时,选择了系统电压值。 |
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