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引用第3楼sinian519于2007-08-31 16:48发表的 :6 E" d2 G, _, x
我也不是很熟悉,请看标准UL153,Clause140.2 . k! I# I6 n% @* I) G8 `
根據這個圖就對了.' E/ y/ v! T+ q* ^3 e
. {/ K$ w; Y8 O- n不過根據這個設備的要求, 發現標準存在問題, 請對照上面的圖再看此條, 一直困惑中:' Z9 _7 x7 w0 D9 h. \, M- }9 ?
7 I+ Y8 M# c, @7 K
140.2.5 The measurement circuit for leakage current is to be as illustrated in Figure 140.1. The
- w! f' K: c, cmeasurement instrument is defined in (a) – (c). The meter that is actually used for a measurement is, q! N& t: j- V
required to only indicate the same numerical value for a particular measurement as the defined$ M3 g8 L% K1 ]/ n5 z
instrument. The meter used is not required to have all the attributes of the defined instrument.! _) _1 W, K$ X
a) The meter is to have an input impedance of 1500 ohms resistive shunted by a capacitance
$ l/ ]3 \* u( S aof 0.15 microfarad.; ^5 x: a+ v0 P
b) The meter is to indicate root mean square values which is 1.11 times the average of the fullwave
* I" |8 e+ ~/ ?" g; U v1 Grectified composite waveform of the current through the resistor./ g2 J$ y" j7 O( K. f. P
c) Over a frequency range of 0 – 100 kilohertz, the measurement circuitry is to have a( M0 q }* [9 H# g f+ |
frequency response – ratio of indicated to actual value of current – that is equal to the ratio of" m* `. ?8 c9 @; R$ G' s
the impedance of a 1500 ohm resistor shunted by a 0.15-microfarad capacitor to 1500 ohms. At- P% r4 h& o# n8 g# Z5 L
an indication of 0.5 milliamperes, the measurement is not to have an error of more than 5
" \- p& E8 g& x. V( W4 apercent at 60 hertz. |
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