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引用第2楼roy517于2007-11-06 12:02发表的 :
$ y1 R. e; y1 k; e; L& e为什么呢?能说明原因吗?麻烦了! & v+ P" n3 G3 ~! @/ T
UL13109 U6 s6 j) F8 {
( e7 h2 _. x6 K- W14.2.2 The maximum voltages which may be accessible in accordance with 14.2.1(a) are:0 o L# w2 H5 H4 Q W, }3 w
a) 42.4 V peak for sinusoidal or nonsinusoidal AC;; U3 [+ a8 i4 n
b) 60 V for continuous DC;
7 E. ~; ?* X" y4 w1 |c) 24.8 V peak for DC interrupted at a rate of 200 Hz or less with approximately 50 percent duty cycle; and9 r; Q1 r7 ], l. j, r* n
d) As indicated in Figure 14.3 for combinations of AC and DC.& I3 R6 K: v0 _& Z
For the purpose of this requirement, initial transients lasting less than 200 milliseconds may be ignored. Since short term peak voltage is of interest during tests involving a fault, voltages are to be monitored by using a storage oscilloscope for the first two seconds after any fault is introduced.2 _7 U; s9 b, s1 a
) P2 X% v" f1 C7 M/ d3 ]
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"Since short term peak voltage is of interest during tests involving a fault," |
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