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8.1.4 An accessible part is not considered to be live if
' o8 ]0 \) \ u% ?– the part is supplied at safety extra-low voltage, provided that : ^6 n. D# L3 j- _' J
• for a.c., the peak value of the voltage does not exceed 42,4 V,
8 s7 ~1 N- G% z• for d.c., the voltage does not exceed 42,4 V, % D( V8 H& [' B/ O2 k$ B$ j
or
# C1 S" V! R i! l– the part is separated from live parts by protective impedance. ! b4 x0 }/ Y1 \/ s, J5 S, J, h h
If protective impedance is used, the current between the part and the supply source shall
' R% l$ O8 S) i' P$ s3 b( Bnot exceed 2 mA for d.c., its peak value shall not exceed 0,7 mA for a.c. and
) M& y5 b/ m, O# Z b+ s– for voltages having a peak value over 42,4 V up to and including 450 V, the capacitance & n+ n' E K3 l' f2 [, A; B; o+ c* J
shall not exceed 0,1F, " S4 ]2 U/ f; D2 L6 G
– for voltages having a peak value over 450 V up to and including 15 kV, the discharge shall
, x2 ~! s, U: o" l8 [* Inot exceed 45 C. # Q# @1 A' i2 o
Compliance is checked by measurement, the appliance being supplied at rated voltage.
* q6 m3 [) d) g( tVoltages and currents are measured between the relevant parts and each pole of the supply
; q' l& q) @1 ?3 o# ~source. Discharges are measured immediately after the interruption of the supply.
+ }. y9 e4 Y# M+ hNOTE Details of a suitable circuit for measuring the current are given in figure 4 of IEC 60990.
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) p" P4 a3 \5 y: r, C你的問題似乎比較的偏, 不過測試方法應該沒有問題.
% Y: r5 z! W; u" v& {" U; c
. T2 ]: |3 f/ m4 D8 ^0 u: a4 _) I7 Q* p }
我觉得测量的时候是将无感电阻接在易触及部件和电源的每一级之间,然后测量无感电阻两端的电压放电曲线。 7 D5 Q2 U: q: V6 }% @! r
另外有个担心就是怕两端有高压,会不会把示波器给烧掉呢?
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根據電路圖, 略去Cs不計, 在最大峰值電壓15kV下, 測量腳間電壓為:15000*[Rb/(Rs+Rb)]=15000*[500/(1500+500)]=3750V, 你查查示波器說明書, 估計此電壓範圍應該可以測量不致燒毀.
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1 x; o7 U# i7 ~1 _还有个问题就是,前阵子遇到有人问到干电池灭蚊拍的放电量测量,其格栅的电压在450-15KV的范围内, 要测试其放电量又应该怎么测呢,请注意这是干电池式的,不是充电式,标准中也未提到,所以想问下大家的意见! @2 \# P) |+ u
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不是很熟悉示波器, 更沒做電蚊拍, 估計根據放電圖, 用微積分可以求出放電量. |
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