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本帖最后由 jansle_happy 于 2021-8-13 10:09 编辑
0 N2 z8 E4 P& b7 P" `! u大神看起来,应该不是说figure E只是个列子吧,看起来原文是前面描述了测试电路的特性,然后给出具体的图书如图E啊。 q; b3 \6 P! g
H.8.1.10 ACCESSIBLE PARTS shall not be considered as HAZARDOUS LIVE PARTS if separated from the supply by PROTECTIVE IMPEDANCE.
) q/ D$ Q4 V0 ~H.8.1.10.1 When PROTECTIVE IMPEDANCE is used, the current between the part or parts and either pole of the supply source shall not exceed 0,7 mA (peak value) a.c. or 2 mA d.c;2 d# I! p# W% S
– for frequencies exceeding 1 kHz, the limit of 0,7 mA (peak value) is multiplied by the value of the frequency in kHz but shall not exceed 70 mA (peak value);
3 @! W: x/ T/ @& u5 [" z– for voltages over 42,4 V (peak value) and up to and including 450 V (peak value), the capacitance shall5 V5 h2 m& y" k' {. C3 j
not exceed 0,1 μF;5 ]9 k( X: b3 _& e( f
– for voltages over 450 V (peak value) and up to and including 15 kV (peak value), the product of the capacitance in farads times the potential in volts shall not exceed 45 μC;
& h! I9 N& P, L* V) g6 m– for voltages over 15 kV (peak value), the product of the capacitance in farads times the square of the potential in volts shall not exceed 350 mJ.
$ ]6 x/ u# a! ~, T% D* ^& sCompliance is checked by measurement.' c$ b# g3 q2 U3 X3 u
Voltages and currents are measured between a single ACCESSIBLE PART (or any combination of such parts)' D" s( k4 Z+ _/ ~/ G
and the protective earth conductor. Measurements shall be taken in normal supply configuration, and with# y) [+ v8 p q2 M. r5 ]5 N) K1 `
supply poles interchanged. O1 {: i% Z2 |# i e w
The measuring circuit shall have a total impedance of (1 750 ± 250) W and be shunted by a capacitor such7 ]; H* P; H% q! i# H& q/ `8 R* K
that the time constant of the circuit is (225 ± 15) μs.
# j, L% v- U+ o! C3 |% d% p+ fDetails of a suitable measuring circuit are shown in Figure E.1.3 U, S$ v9 ~4 g, D% q- r
The measuring circuit shall have an accuracy of within 5 % for all frequencies in the range of 20 Hz to 5
7 Z1 L; p7 P4 ZkHz. For frequencies above 5 kHz, alternative methods of measurement are required. |
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