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引用第3楼sinian519于2007-08-31 16:48发表的 :
* ~; O3 {; ]2 G我也不是很熟悉,请看标准UL153,Clause140.2 + q2 K2 g1 w- D3 f+ a
根據這個圖就對了.1 @6 r* O+ x! ]: [
% }8 R: q# {( w, @; z3 A2 l; |; O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+ K1 U3 p" G* a! V: `9 W$ \% f; ~; t7 Y$ c/ c* [- @
140.2.5 The measurement circuit for leakage current is to be as illustrated in Figure 140.1. The
* x5 w! o$ S& U% R1 Smeasurement instrument is defined in (a) – (c). The meter that is actually used for a measurement is
, o) a0 T" M" l7 }& c( d5 Grequired to only indicate the same numerical value for a particular measurement as the defined2 j4 R O. _& ^
instrument. The meter used is not required to have all the attributes of the defined instrument.
8 P4 u) l7 }, _; Ba) The meter is to have an input impedance of 1500 ohms resistive shunted by a capacitance! M. O7 s* n- N o& G9 \8 K
of 0.15 microfarad.
& B' h W5 s& H. ~3 Zb) The meter is to indicate root mean square values which is 1.11 times the average of the fullwave) V1 l9 X8 A7 Y) ^9 U! a6 u( U4 Y
rectified composite waveform of the current through the resistor.. h' u* h/ O" `: Y: w+ Q& l& j, ?
c) Over a frequency range of 0 – 100 kilohertz, the measurement circuitry is to have a
4 @' x L, s, O1 bfrequency response – ratio of indicated to actual value of current – that is equal to the ratio of- n) l% }- a+ G( e0 A- S
the impedance of a 1500 ohm resistor shunted by a 0.15-microfarad capacitor to 1500 ohms. At
" R4 E/ T! [, J) m# V# v) Han indication of 0.5 milliamperes, the measurement is not to have an error of more than 5
- U$ \+ w4 s& ^ v. ^percent at 60 hertz. |
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