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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。
% }: x$ K; C3 l9 S: Q4 W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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借上面兄弟的标准描述:' I, e2 A, z! _ I L$ p& [4 V
For an AC MAINS SUPPLY not exceeding 300 V r.m.s. (420 V peak):
' `; b+ C3 l+ E1 z5 t! Ba) if the PEAK WORKING VOLTAGE does not exceed the peak value of the AC MAINS SUPPLY
L2 Y. O1 }2 {voltage, minimum CLEARANCES are determined from Table 2K;9 m! w6 J9 s8 L3 \1 |% l
b) if the PEAK WORKING VOLTAGE exceeds the peak value of the AC MAINS SUPPLY voltage,
& u" R4 `( Y( ]( Jthe minimum CLEARANCE is the sum of the following two values:4 E' ^! b6 d& q! i% C. a; M
• the minimum CLEARANCE from Table 2K; and( c8 Z# M0 b0 E4 _6 S
• the appropriate additional CLEARANCE from Table 2L.# {$ P. s0 t' a9 D5 [" s! Z( T; u
+ B' g" |4 n! Q* E
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 P* `! D# L
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.
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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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