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发表于 2014-6-25 10:49
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我看IEC 60950:2013 表2K上有这样两句话。
5 r% _+ g0 A3 A' o3 A1. If the PEAK WORKING VOLTAGE exceeds the peak value of the AC MAINS SUPPLY voltage, linear interpolation is permitted between the nearest two points, the calculated minimum CLEARANCE being rounded up to the next higher 0,1 mm increment.6 y/ D8 {) s) N' {. _: o$ H5 |" ]
; U$ X, l' \4 h- d2. a If the PEAK WORKING VOLTAGE exceeds the peak value of the AC MAINS SUPPLY voltage, see use the peak value of the AC MAINS SUPPLY voltage in this column and use Table 2L in accordance with 2.10.3.3 b) regarding additional CLEARANCES
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照这两句话的意思我用线插入法这么算的Table 2K,496V X 4.0/420V=4.7mm, 再加上Table 2L的附加绝. T c2 d( [0 @4 @; s
缘值 4.7 + 0.2=4.9mm 电气间隙
T1 Y7 Q" }$ \9 K
6 C( w2 _7 m! v+ v: }* K! P: o! `爬电距离查表Table 2N用线插入法这么算, 240V X 2.5/250V=4.8mm- H% m2 A2 L N5 m, P* Y
' [, p; \. A. O9 k8 n" e原文If the minimum CREEPAGE DISTANCE derived from Table 2N is less than the applicable
* V. Y* m& d2 N# ^minimum CLEARANCE, that value of minimum CLEARANCE shall be applied as the minimum & ]; B0 q$ R& g- _: P4 X1 Q
CREEPAGE DISTANCE. / s! z7 Q1 @' s
所以就变成了,
( X9 p Y; \0 V9 e! t4 D爬电距离4.9 和电气间隙 4.9mm
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