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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。! D- X) x1 r5 `( R3 q7 H. E
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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8 g8 k$ e* t8 p8 K" G借上面兄弟的标准描述:
1 L4 @0 h3 h( [3 A; T" s7 @For an AC MAINS SUPPLY not exceeding 300 V r.m.s. (420 V peak):
( x' }! I- ~4 p# fa) if the PEAK WORKING VOLTAGE does not exceed the peak value of the AC MAINS SUPPLY! P7 O# w$ ~, N( X6 B6 W
voltage, minimum CLEARANCES are determined from Table 2K;' @2 h7 n D4 C6 F4 \
b) if the PEAK WORKING VOLTAGE exceeds the peak value of the AC MAINS SUPPLY voltage,
a( n; p6 T9 d$ U+ y- t1 D; Nthe minimum CLEARANCE is the sum of the following two values:
1 q- p) m; P* ]- w- |6 M/ d• the minimum CLEARANCE from Table 2K; and
' n$ h1 u" X1 l4 c" g• the appropriate additional CLEARANCE from Table 2L.
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; f* T: z6 `5 z0 u" }8 m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.
2 C3 g% p" T7 c* H6 T7 ^2 K2 c$ q! DPEAK 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.0 c: l4 G* c! W. O2 A" T% C
- ]9 p$ A1 `! Y m! e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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