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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。+ ~8 I& r$ I) o% C. I' b
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。( e0 ^- k3 ~/ W; Z8 w
: Q) T* K! a' b2 D ?/ j2.4 Limited current circuits
% F, t5 h3 c/ o; g; m% Q2.4.2 Limit values& q; o% T: b/ {* p5 c
For frequencies not exceeding 1 kHz, the steady-state current drawn through a non-inductive
% g! d9 q+ v e. K }5 fresistor of 2 000 Ω ± 10 % connected between any two parts of a LIMITED CURRENT CIRCUIT, or( p8 B C$ n4 s% d! q
between any such part and earth (see 1.4.9), shall not exceed 0,7 mA peak, or 2 mA d.c.
, W s) s$ r0 P& C- g; t5 rFor frequencies above 1 kHz, the limit of 0,7 mA is multiplied by the value of the frequency in% ~2 Y5 R: {5 G. `4 h) H& A9 X. h
kilohertz but shall not exceed 70 mA peak.
6 M7 A9 K& u6 ], y* z; rAlternatively, it is permitted to use the measuring instruments of Annex D instead of the noninductive
N8 I, x/ I4 w# T [' Nresistor of 2 000 Ω ± 10 % mentioned above.# e( j' V* ?. Q4 |. y. O
。。。4 `. i2 t; d5 i/ Y1 R" y# ]
* R5 z, D k$ z
2.4.3 Connection of limited current circuits to other circuits
. ^: Q1 \5 V! MLIMITED CURRENT CIRCUITS are permitted to be supplied from or connected to other circuits,0 g# R6 Q' b+ A) b
provided that the following conditions are met:& P, g# o7 O5 b9 N: s# V
− the LIMITED CURRENT CIRCUIT meets the limits of 2.4.2 under normal operating conditions;- A) P* D/ z4 I
− the LIMITED CURRENT CIRCUIT continues to meet the limits of 2.4.2 in the event of a single) ^7 a0 |# f% A' d9 b% F9 K3 G/ Q
failure of any component or insulation in the LIMITED CURRENT CIRCUIT, or of any component7 H& e& w$ G* K/ ^# K% G
or insulation in t he other circuit to which it is connected.. t6 \1 J$ e( T8 N
If a LIMITED CURRENT CIRCUIT is connected to one or more other circuits, the LIMITED CURRENT
% d) P8 o, @; v& e! ]CIRCUIT is that part which complies with the requirements of 2.4.1.& w0 O+ k$ @9 R2 a
- N. \( F) I0 {在IEC 60950-1的限流电路(也就是LCC)的一般适用情形:; e5 L: d2 j* a1 _$ b
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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