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引用第3楼sinian519于2007-08-31 16:48发表的 :
8 m" @) L2 T. c+ M" J我也不是很熟悉,请看标准UL153,Clause140.2 - o+ z* _$ k7 A% j$ [& C, ^
根據這個圖就對了.8 M2 ]4 k; V4 N+ ~7 e+ D
* U- x- e' @& u' b. X- 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:- L7 ?& z0 M3 ?6 ?
% D M* l# E) l+ N; o
140.2.5 The measurement circuit for leakage current is to be as illustrated in Figure 140.1. The0 R' a, }/ G3 ^# d% A0 V4 u! l
measurement instrument is defined in (a) – (c). The meter that is actually used for a measurement is" E6 R+ m" q/ m: U& X
required to only indicate the same numerical value for a particular measurement as the defined
+ H1 ~5 Y+ H4 e0 d% u, sinstrument. The meter used is not required to have all the attributes of the defined instrument.
+ l. p- B8 G2 v- i. Q$ Wa) The meter is to have an input impedance of 1500 ohms resistive shunted by a capacitance
2 O; Q8 p" E% pof 0.15 microfarad." f2 w3 o. E( L! _) `
b) The meter is to indicate root mean square values which is 1.11 times the average of the fullwave
Y: ?8 Q4 P: Z4 K* hrectified composite waveform of the current through the resistor.
' Y4 p) ~5 b, k3 nc) Over a frequency range of 0 – 100 kilohertz, the measurement circuitry is to have a
7 m0 o7 O2 l/ {. s. s8 Mfrequency response – ratio of indicated to actual value of current – that is equal to the ratio of
) V# z- m( S. U, tthe impedance of a 1500 ohm resistor shunted by a 0.15-microfarad capacitor to 1500 ohms. At" ?) M0 K& m' y+ T* o( s; m
an indication of 0.5 milliamperes, the measurement is not to have an error of more than 5
, Y3 P6 H8 {) U+ P8 Ipercent at 60 hertz. |
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