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這里第一版標準和第二版標準在Clearance上的算法有很大的不同,舊標準一般不用內差法即可,但新標準是需要的 請見下面此處的對比:
# U% _) K, u/ T& T" xFor PRIMARY CIRCUITS operating on nominal AC MAINS SUPPLY voltages up to 300 V, if the PEAK WORKING6 J) |+ L" O( S) U
VOLTAGE in the circuit exceeds the peak value of the AC MAINS SUPPLY voltage, the minimum
) `/ P2 H% |1 ~5 P8 {% C/ `CLEARANCE for the insulation under consideration is the sum of the following two values:5 B: Y8 R! k. Q* W
– the minimum CLEARANCE value from table 2H for a WORKING VOLTAGE equal to the AC7 v$ H' O) y7 ] t$ ?' i
MAINS SUPPLY voltage; and& T9 c7 ^4 i |+ x, x+ `3 ~, y
– the appropriate additional CLEARANCE value from table 2J.- i4 z+ ]* c8 A, S9 w4 Q
(舊標準)% { P4 ?5 ` C+ S0 U
For an AC MAINS SUPPLY not exceeding 300 V r.m.s. (420 V peak):3 n4 @% J' k F0 ?4 y
a) if the PEAK WORKING VOLTAGE does not exceed the peak value of the AC MAINS SUPPLY2 j' U- }- a7 i) m0 `" V
voltage, minimum CLEARANCES are determined from Table 2K;0 W8 r+ R' \9 C) n( X! }
b) if the PEAK WORKING VOLTAGE exceeds the peak value of the AC MAINS SUPPLY voltage,& U4 b( y ` X& T4 D
the minimum CLEARANCE is the sum of the following two values:
$ r, C1 I! \) P) i• the minimum CLEARANCE from Table 2K; and
3 x+ ~- H ^7 w+ Q• the appropriate additional CLEARANCE from Table 2L
6 L7 t: Q$ s) S% u(新標準)
# D% \9 ]: o5 ~$ f& M- {. k* r所以Clearance相對新標準嚴苛些了. |
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发表于 2009-2-28 14:02
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