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正确认案件 4.6mm, 且现在所有的认证单位都接受这种算法(TUV, UL, NEMKE, ITS都接受的),并且从标准出发,也是有根据,是正确的。. R6 F( D# Y- s2 w7 S+ p8 a
重点: 请不要忘记表格2K, “PEAK WORKING VOLTAGE a”, 在峰值电压有备注一个小“a”, 对应到这个表格下面的备注,就是“a If the PEAK WORKING VOLTAGE exceeds the peak value of the AC MAINS SUPPLY voltage, see 2.10.3.3 b) regarding additional CLEARANCES.
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$ R" ^# L$ Q5 p: B. K L0 d借上面兄弟的标准描述:( v% k% e: n1 b5 s6 ]2 i
For an AC MAINS SUPPLY not exceeding 300 V r.m.s. (420 V peak):
% B$ G" e8 e$ s3 _a) if the PEAK WORKING VOLTAGE does not exceed the peak value of the AC MAINS SUPPLY* }' E/ v; B; g+ J+ L9 y
voltage, minimum CLEARANCES are determined from Table 2K;% ~$ f5 r' o4 c0 f, @
b) if the PEAK WORKING VOLTAGE exceeds the peak value of the AC MAINS SUPPLY voltage,' Y& b. b% e9 S7 L/ T5 o
the minimum CLEARANCE is the sum of the following two values:
1 A$ j. @8 c0 w) _/ }% m1 [9 \• the minimum CLEARANCE from Table 2K; and* a6 d( @* y* T/ V: V4 u" P
• the appropriate additional CLEARANCE from Table 2L.
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故我们通过确认 Upeak=612V, 根据表格2K (420V) ,要求4.0 mm, 然后再根据2L(612V), 再增加0.6 mm.
! Z o% |5 J5 C" [- ?3 ]PEAK WORKING VOLTAGE a,请不要忘记表格2K, 在峰值电压有备注一个小“a”, 对应到这个表格下面的备注,就是“a If the PEAK WORKING VOLTAGE exceeds the peak value of the AC MAINS SUPPLY voltage, see 2.10.3.3 b) regarding additional CLEARANCES.”,所以说,最终还是用表格2K加上2L的距离,就等于最终的距离要求。故距离要求应该是 4.6 mm." q3 {, Y6 ~4 K
0 G: \( C" K/ {0 x问题已经明了,但有一个疑问是标准表格2K中提到的线性插入法,说是可以用,但基本目前的认证单位不会去用,且在标准第一版中是“3) For WORKING VOLTAGES between 2 800 V peak or d.c. and 42 000 V peak or d.c., linear interpolation is permitted between the nearest two points, the calculated spacing being rounded up to the next higher 0,1 mm increment.”,有一点不一样。 |
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