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引用第2楼roy517于2007-11-06 12:02发表的 :
' J5 H! ^; k# O% v为什么呢?能说明原因吗?麻烦了! . u1 b5 I) X' ^6 H! c; [9 z/ D
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14.2.2 The maximum voltages which may be accessible in accordance with 14.2.1(a) are:
7 `, C) }. ~8 a8 T3 T6 N1 `2 za) 42.4 V peak for sinusoidal or nonsinusoidal AC;) k1 Q ?2 o5 r+ I! a7 R; F
b) 60 V for continuous DC;
* q. u+ K1 U$ B9 j1 `c) 24.8 V peak for DC interrupted at a rate of 200 Hz or less with approximately 50 percent duty cycle; and/ L( Q+ g5 Q6 [# u3 }& f [
d) As indicated in Figure 14.3 for combinations of AC and DC.
# X8 W6 P' J) s- d* P: ?6 pFor 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.6 u, Y* P P9 n; m# F6 A! b- V6 ~* y% g
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4 J. t' G9 c. a, w# B& f7 P"Since short term peak voltage is of interest during tests involving a fault," |
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