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引用第3楼sinian519于2007-08-31 16:48发表的 :1 K O$ }# @& S2 X( m
我也不是很熟悉,请看标准UL153,Clause140.2 - Z' p; S# C3 y1 A( Z
根據這個圖就對了.3 Q3 N+ }2 H5 Q
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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:7 R3 }1 z9 F8 h% [
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140.2.5 The measurement circuit for leakage current is to be as illustrated in Figure 140.1. The
) W5 _4 o! }: J6 x5 @- s7 d5 Hmeasurement instrument is defined in (a) – (c). The meter that is actually used for a measurement is
- c3 N: y! a2 k7 drequired to only indicate the same numerical value for a particular measurement as the defined( \! q" F, Y" o! W y7 V. a
instrument. The meter used is not required to have all the attributes of the defined instrument.0 F& K; T0 [& Y% h5 a( j
a) The meter is to have an input impedance of 1500 ohms resistive shunted by a capacitance% ^7 q! E0 n6 _7 l6 J. j& M
of 0.15 microfarad.
7 ~# E3 `# @0 e$ r* L$ r* _# q" Kb) The meter is to indicate root mean square values which is 1.11 times the average of the fullwave
. W2 ]3 ^) w# n5 I. a `rectified composite waveform of the current through the resistor.1 t% F! \" P2 ~3 M# b# i
c) Over a frequency range of 0 – 100 kilohertz, the measurement circuitry is to have a- W0 G9 K+ j3 l) R
frequency response – ratio of indicated to actual value of current – that is equal to the ratio of, q7 [# W! w5 G- ]0 j- x, v. Z& T
the impedance of a 1500 ohm resistor shunted by a 0.15-microfarad capacitor to 1500 ohms. At4 s1 }6 R2 u0 [5 N! J. W1 }
an indication of 0.5 milliamperes, the measurement is not to have an error of more than 59 ~. D1 c. I6 S. `
percent at 60 hertz. |
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