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因輸入電源不見的N線與地是等電位, 照我們的做法, I類需把N線跟地連接, 若為II類需將输出段的负极與N線相连, 此主要目的是代測物primary & secondary間需有一參考點, 如此才能量测到最大的工作电压.
! x$ }/ l* \& b$ c$ G6 i! r若要說標準哪有, 個人認為標準也沒寫的很清楚, 但IEC60950-1:2001 cl.2.10.2 or 60950-1:2005 cl. 2.10.2.1a) & b) 可以用來參考
; ]' [) `$ y$ [, M$ Y! H4 L% pcl. 2.10.2.1 a) Unearthed accessible conductive parts shall be assumed to be earthed.
) g0 Q8 c' ?+ L, r2 c! ~8 q" X7 n& Xcl. 2.10.2.1 b) If a transformer winding or other part is floating (it is not connected to a circuit that establishes its potential relative to earth), it shall be assumed to be earthed at the point by which the highest working voltage is obtained. |
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