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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。' f$ a8 c6 [9 s& p8 O6 T
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.* J1 q' F4 j' v: n' X
$ G4 R* v6 t6 e/ ]1 Q) |借上面兄弟的标准描述:/ @" N+ g$ T2 Z; T( x' q
For an AC MAINS SUPPLY not exceeding 300 V r.m.s. (420 V peak):
$ e" D4 f n9 G+ D/ U# Na) if the PEAK WORKING VOLTAGE does not exceed the peak value of the AC MAINS SUPPLY& u1 P; W% K3 n [5 ]$ |) @8 M
voltage, minimum CLEARANCES are determined from Table 2K;/ Y. r# i+ s5 ^5 G/ P
b) if the PEAK WORKING VOLTAGE exceeds the peak value of the AC MAINS SUPPLY voltage,' |! s+ J* l' |2 ]! }
the minimum CLEARANCE is the sum of the following two values:3 F: X; \* V8 \; L* }
• the minimum CLEARANCE from Table 2K; and
3 S# n: M# G1 M& x, f2 o6 y* ~) ]• the appropriate additional CLEARANCE from Table 2L.
4 J7 b2 x- Y/ U7 d, [' L
# `& s% z8 T+ H$ j: B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.
' s, o$ ~1 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.9 N% f3 N3 n! b( x. Z& x
+ l4 m- D. l+ t; }4 u/ i
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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