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引用第3楼sinian519于2007-08-31 16:48发表的 :
9 ?5 h/ T" D2 D8 k5 E我也不是很熟悉,请看标准UL153,Clause140.2
根據這個圖就對了.: C7 p& e* n( ]" }
# c' E5 ]6 w; 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:
/ H! m1 W2 [% H8 z- Z, ?. S$ C, f: c
140.2.5 The measurement circuit for leakage current is to be as illustrated in Figure 140.1. The
~% C) S% N8 n' X7 w/ Mmeasurement instrument is defined in (a) – (c). The meter that is actually used for a measurement is7 r( n" G4 m( I7 |
required to only indicate the same numerical value for a particular measurement as the defined
; S7 l# H/ ?( x' T' l- G0 f: Winstrument. The meter used is not required to have all the attributes of the defined instrument.
1 N' Z* q+ Q' S8 f+ t/ L2 N& `& fa) The meter is to have an input impedance of 1500 ohms resistive shunted by a capacitance& Q$ a8 z. K0 t" o" B4 C
of 0.15 microfarad.9 B/ X( ]" i' l3 H, a, D% O/ x
b) The meter is to indicate root mean square values which is 1.11 times the average of the fullwave
# h# e$ L- V& X( z% f: [- m. ]rectified composite waveform of the current through the resistor.
8 H- l8 o& d" o1 s |5 K' wc) Over a frequency range of 0 – 100 kilohertz, the measurement circuitry is to have a
6 {, Z3 U4 F; `% m( T0 d1 W7 F$ afrequency response – ratio of indicated to actual value of current – that is equal to the ratio of
2 L* C U7 [* c+ s7 b( jthe impedance of a 1500 ohm resistor shunted by a 0.15-microfarad capacitor to 1500 ohms. At
1 M! Y$ ^5 {% L, h" ~* tan indication of 0.5 milliamperes, the measurement is not to have an error of more than 5
9 E, p1 T' \8 @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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