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引用第3楼sinian519于2007-08-31 16:48发表的 :
+ g) z( C+ E! L+ W! p' K! {我也不是很熟悉,请看标准UL153,Clause140.2 7 ?7 l0 l# N" X" o! [- ?7 }
根據這個圖就對了.- W9 z8 k1 G& |8 P+ y
! H/ E' A' C7 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:3 L T M9 A+ L$ E) R
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140.2.5 The measurement circuit for leakage current is to be as illustrated in Figure 140.1. The0 h# |( q" K ~- P7 i7 q1 g3 \( |
measurement instrument is defined in (a) – (c). The meter that is actually used for a measurement is/ |( A! }/ H/ P
required to only indicate the same numerical value for a particular measurement as the defined
' g l9 T+ O! L& T, G3 L# Q8 `" Binstrument. The meter used is not required to have all the attributes of the defined instrument.
2 N# ^, q1 y8 w$ N& Ra) The meter is to have an input impedance of 1500 ohms resistive shunted by a capacitance; c. e) J9 d/ q. k9 K1 S
of 0.15 microfarad./ p- @! N* ?* E$ Z# B& x
b) The meter is to indicate root mean square values which is 1.11 times the average of the fullwave! `5 q) H- J4 [9 c
rectified composite waveform of the current through the resistor.
h. `, p5 j+ z8 ~+ d7 `$ I' [7 A5 Uc) Over a frequency range of 0 – 100 kilohertz, the measurement circuitry is to have a
7 \* r1 M f, q# @7 ^frequency response – ratio of indicated to actual value of current – that is equal to the ratio of) R2 z/ z8 M) p0 h" I0 i
the impedance of a 1500 ohm resistor shunted by a 0.15-microfarad capacitor to 1500 ohms. At
; E* ~! @# G9 j( m, t1 Kan indication of 0.5 milliamperes, the measurement is not to have an error of more than 5
$ v$ f- w8 ?3 `0 jpercent at 60 hertz. |
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