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引用第3楼sinian519于2007-08-31 16:48发表的 :
( @6 I8 R+ @& R! D* ?我也不是很熟悉,请看标准UL153,Clause140.2
, u# d) h% f; x! `6 d6 s根據這個圖就對了.2 E9 X# j7 J0 }/ [/ H( @5 E
, G0 e: }$ f/ l; @: m) _1 h9 h7 u
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:
- F! K* T! `+ Q7 p7 m3 ?' o" v2 k9 s9 c$ E% Y* q/ p) x5 q8 o
140.2.5 The measurement circuit for leakage current is to be as illustrated in Figure 140.1. The
; z) P# ~& S; J& J1 S1 emeasurement instrument is defined in (a) – (c). The meter that is actually used for a measurement is9 L1 D' s3 Y Q0 V$ z% t: U# j
required to only indicate the same numerical value for a particular measurement as the defined H3 L7 [0 [( d5 X( b" p5 |
instrument. The meter used is not required to have all the attributes of the defined instrument.+ M7 x7 ~- C2 J K7 ^
a) The meter is to have an input impedance of 1500 ohms resistive shunted by a capacitance0 d0 u1 c8 [7 u! u1 B* d# R: A
of 0.15 microfarad.
/ C& {9 t4 R0 d) Qb) The meter is to indicate root mean square values which is 1.11 times the average of the fullwave! ]7 t: K$ N4 J# T+ G/ Y
rectified composite waveform of the current through the resistor.$ M. u n S1 H$ Z
c) Over a frequency range of 0 – 100 kilohertz, the measurement circuitry is to have a; k+ }9 J- H9 J) D/ l$ u3 W
frequency response – ratio of indicated to actual value of current – that is equal to the ratio of6 q# E' [- Y( V: X9 K" |
the impedance of a 1500 ohm resistor shunted by a 0.15-microfarad capacitor to 1500 ohms. At5 ?" z7 E. \# A
an indication of 0.5 milliamperes, the measurement is not to have an error of more than 5
: z4 n \3 q2 D$ z7 }/ Upercent 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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