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你所说的使用220V但电流限制0.7mA是哪类的产品?在IEC 60950-1标准的LCC章节定义中,电压并不是最终决定因素,而是需要考量该电压的环境就是:与LCC电路的连接须符合Clause 2.4.3前提下,该LCC电路的分类和测量方式下不超过Clause 2.4.2规定限值的,才是人体可以直接触摸的。
+ {6 G! P! q2 ~. |注:要考虑测量时使用2000欧无感电阻、考虑电压的频率、还有该电路的电容量这些必不可少的因素。
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; A# ^& n& `6 j% ?0 _- R2.4 Limited current circuits1 [& a. e% b' q
2.4.2 Limit values5 B9 _ m% {1 E& @/ H) e
For frequencies not exceeding 1 kHz, the steady-state current drawn through a non-inductive
: D% [6 A" v& [5 K) A. h: fresistor of 2 000 Ω ± 10 % connected between any two parts of a LIMITED CURRENT CIRCUIT, or; `. e+ t" Z, [& k6 w* \& t- U0 c: n9 G
between any such part and earth (see 1.4.9), shall not exceed 0,7 mA peak, or 2 mA d.c.
# I3 @* y6 \- A+ z0 QFor frequencies above 1 kHz, the limit of 0,7 mA is multiplied by the value of the frequency in
; o$ `3 m$ a4 T2 {kilohertz but shall not exceed 70 mA peak.
: O+ @' p: g5 q: Z- T7 ^Alternatively, it is permitted to use the measuring instruments of Annex D instead of the noninductive
, W: Q( K; ~2 P5 \/ m# Tresistor of 2 000 Ω ± 10 % mentioned above.
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2.4.3 Connection of limited current circuits to other circuits8 Q, y+ y" g) I I( j
LIMITED CURRENT CIRCUITS are permitted to be supplied from or connected to other circuits,* G- t3 a( a: h5 B% M' e- O) ~$ b
provided that the following conditions are met: u" k) e. @- W; {* T2 H' Z) k z
− the LIMITED CURRENT CIRCUIT meets the limits of 2.4.2 under normal operating conditions;
' ]& W/ q% D8 I0 ^− the LIMITED CURRENT CIRCUIT continues to meet the limits of 2.4.2 in the event of a single- @( y- _6 x3 y) n) }+ l
failure of any component or insulation in the LIMITED CURRENT CIRCUIT, or of any component+ c6 G4 d1 J; o6 m) v! x5 H
or insulation in t he other circuit to which it is connected.* l2 T) Q8 ~7 ~6 L5 N
If a LIMITED CURRENT CIRCUIT is connected to one or more other circuits, the LIMITED CURRENT
# ^ m( W/ Q2 f8 ]CIRCUIT is that part which complies with the requirements of 2.4.1.) z9 f# J6 i* {4 i. W" {* j
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在IEC 60950-1的限流电路(也就是LCC)的一般适用情形:
3 X8 R: x" ~' B; Z某种高电压输出的电路,该电路在设计上能保证在正常和单一故障条件下,从电路流出的电流都是非危险的电流。通俗的讲法是,该电路虽然电压高但人是可以直接触摸的。 |
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