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引用第3楼sinian519于2007-08-31 16:48发表的 :* [7 J4 f# x) ?: I
我也不是很熟悉,请看标准UL153,Clause140.2
根據這個圖就對了.
' C$ |" V# t7 W- k/ \% \
1 E- K0 L' b3 r% H* {* r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:- G) x) {5 V7 ~3 D
9 Y7 z- s. {* A! @' \" a2 `140.2.5 The measurement circuit for leakage current is to be as illustrated in Figure 140.1. The* T: L, W b' R }% Q
measurement instrument is defined in (a) – (c). The meter that is actually used for a measurement is
+ T8 [2 H2 l! U# Trequired to only indicate the same numerical value for a particular measurement as the defined# Q4 D/ c) [1 l0 [: o1 E
instrument. The meter used is not required to have all the attributes of the defined instrument.' @7 O% ?; Q+ R$ j5 u4 h' r# [
a) The meter is to have an input impedance of 1500 ohms resistive shunted by a capacitance
4 f6 i3 F1 E9 K8 _1 yof 0.15 microfarad.3 N- ^* y# B+ B/ \
b) The meter is to indicate root mean square values which is 1.11 times the average of the fullwave
1 g5 U: `5 s" L0 H. I! U8 f+ Srectified composite waveform of the current through the resistor.
- `/ F0 Z9 H% ]* _. m; F xc) Over a frequency range of 0 – 100 kilohertz, the measurement circuitry is to have a9 G0 i2 i7 Y# ~; b) @ V, D
frequency response – ratio of indicated to actual value of current – that is equal to the ratio of
6 t# @7 g% }7 D% c, ^the impedance of a 1500 ohm resistor shunted by a 0.15-microfarad capacitor to 1500 ohms. At: J e; |4 S, t7 z+ L
an indication of 0.5 milliamperes, the measurement is not to have an error of more than 5
3 h# N, _+ D3 N( E0 {6 @& N' q" `percent at 60 hertz. |
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发表于 2007-8-31 16:06
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发表于 2007-8-31 16:53
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