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好像大家都没有兴趣，这样我来抛砖引玉！$ a, [" Y/ ?* h6 u
" K1 r. T7 c/ GProtective imdependance(保护阻抗）是我们经常看到的，但是你理解吗？
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. x6 u( e7 d6 q l @, l u9 udefinition:
! J3 O& l0 a" I: ]protective impedance
9 \5 D- k1 g! vimpedance connected between live parts and accessible conductive parts of class II; k) V5 i' b7 {, ]
constructions so that the current, in normal use and under likely fault conditions in the. f- X% Z8 n% |9 @
appliance, is limited to a safe value
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0 Z, i, s C' K! m4 I+ }8.1.4
5 q! c, H. l. n" A B4 E3 T& M8.1.4 An accessible part is not considered to be live if or" }4 ]- v1 u% }1 E* M' G7 X. {
– the part is separated from live parts by protective impedance.
8 o! }3 `6 F$ S$ mIf protective impedance is used, the current between the part and the supply source shall1 p A5 N% H: r# ^
not exceed 2 mA for d.c., its peak value shall not exceed 0,7 mA for a.c. and
! }! [" a; b+ }9 w1 e8 w– for voltages having a peak value over 42,4 V up to and including 450 V, the capacitance
; \/ d% G. V5 I( @shall not exceed 0,1 μF,( X4 r6 r/ F" m7 y4 Z7 Z/ o
– for voltages having a peak value over 450 V up to and including 15 kV, the discharge shall5 N; o; P! F! |7 l# T( g" O
not exceed 45 μC,
9 M4 d. x4 l Z7 F– for voltages having a peak value over 15 kV, the energy in the discharge shall not exceed
$ r5 m% R- p4 s350 mJ.
1 d& A# r& s( j0 |1 KCompliance is checked by measurement, the appliance being supplied at rated voltage.
/ c2 J, Z4 I) [! ^Voltages and currents are measured between the relevant parts and each pole of the supply! O# j) O1 B# n: v3 ^
source. Discharges are measured immediately after the interruption of the supply. The6 u m2 }$ H, N5 H
quantity of electricity and energy in the discharge is measured using a resistor having a
4 U7 O. X1 z( D$ c& A9 ~" unominal non-inductive resistance of 2 000 Ω.
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4 r; G h' f! i; k, lCl13.1
( g+ g: r- T/ e; _. Q4 a9 D4 MProtective impedance and radio interference filters are disconnected before carrying out the4 o+ ]8 K* `7 F7 ~+ p! r, X4 w
tests.' d3 }7 g- V* k1 m' U5 }8 t* d
5 q2 N3 n. h* F
Cl16.15 J7 N# y# E9 a* L1 [
Protective impedance is disconnected from live parts before carrying out the tests.
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- r9 l1 I5 e- n8 s0 H+ W& U- ~Cl22.27
/ U, K: @7 F" m2 M22.27 Parts connected by protective impedance shall be separated by double insulation' `* D+ j* q; A) U. T
or reinforced insulation./ @+ ]4 K+ e4 h
Compliance is checked by the tests specified for double insulation or reinforced insulation' R0 F- k" ? W- Q% b; L9 Q
$ x+ ?/ L1 I3 [6 NCl22.37
1 ~0 o7 E" X& g" @) d0 ^22.37 For class II appliances, capacitors shall not be connected to accessible metal parts! H) v1 B8 a6 Q/ S- q3 `
and their casings, if of metal, shall be separated from accessible metal parts by2 k3 g( O& i; I; @+ _& J
supplementary insulation.
4 g- u" R. s9 {' sThis requirement does not apply to capacitors complying with the requirements for protective1 j1 B9 b0 h- i8 Q9 y
impedance specified in 22.42.% h& \; Q; P) X
& Q# z5 V$ m% J# L0 @, ^5 X/ s, P% HCl22.42
( s. ^4 G3 r8 J S22.42 Protective impedance shall consist of at least two separate components whose
! C% v C5 `* `" g/ h; ]impedance is unlikely to change significantly during the lifetime of the appliance. If any one of- x, H; V z" U! K7 ~0 A9 x! u
the components is short-circuited or open-circuited the values specified in 8.1.4 shall not be1 J) a, S# P8 e
exceeded.5 w$ R2 d) G9 b, w2 q& q/ c! Z! x
NOTE Resistors complying with test a) of subclause 14.1 of IEC 60065 and class Y capacitors complying with
0 ~: ?, [2 `$ k5 O7 ?# z. s- oIEC 60384-14 are considered to be components having a sufficiently stable impedance.* V6 h6 l9 V- I2 e0 x% a: a
Compliance is checked by inspection and by measurement.
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& \2 T/ A4 q! q1 O; M8 @3 w) E( J |5 y~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# I2 c) G2 ]' i* ]# ?3 o- D这么多的要求中，你碰到过什么样的案例？是怎样评估和解决的？ 一起拿出来分享吧！ |
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发表于 2010-3-3 16:55
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