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好像大家都没有兴趣,这样我来抛砖引玉!
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" r" {* [/ m* v D% {: w# zProtective imdependance(保护阻抗)是我们经常看到的,但是你理解吗?
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# z- a ]; S! H; s) Idefinition: " L: p% Y# X3 n/ {, [7 ~/ k5 Q) t
protective impedance
5 r5 w, M: ~- ]# I5 P9 qimpedance connected between live parts and accessible conductive parts of class II
/ H+ K: N' W- l+ econstructions so that the current, in normal use and under likely fault conditions in the8 c4 b7 t3 ~* k% k: Q5 |
appliance, is limited to a safe value
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8.1.47 |9 |2 A f2 M2 `& z$ b3 ]* ~8 i! W
8.1.4 An accessible part is not considered to be live if or
5 P2 i. a) V! |' k5 @. |) ]8 S: n" d– the part is separated from live parts by protective impedance.' W+ l8 F$ }' w# _
If protective impedance is used, the current between the part and the supply source shall
0 N! T6 Z8 Q* vnot exceed 2 mA for d.c., its peak value shall not exceed 0,7 mA for a.c. and
: \9 @# U1 {) D r5 ?– for voltages having a peak value over 42,4 V up to and including 450 V, the capacitance
6 f& L. J/ r2 G$ Q* i/ wshall not exceed 0,1 μF,
F$ `9 w* L9 Y– for voltages having a peak value over 450 V up to and including 15 kV, the discharge shall
# E# z% H1 y/ j7 rnot exceed 45 μC,
`& [1 O3 M' w- e, H' c– for voltages having a peak value over 15 kV, the energy in the discharge shall not exceed
$ ]0 ]3 v3 u1 t350 mJ.
5 u# b2 f4 g" TCompliance is checked by measurement, the appliance being supplied at rated voltage.$ j- e& p$ G' O: a' q; A
Voltages and currents are measured between the relevant parts and each pole of the supply
2 [2 p6 ` \! p1 h3 r U9 G8 g) Bsource. Discharges are measured immediately after the interruption of the supply. The; I1 n* L" m1 q2 l" B
quantity of electricity and energy in the discharge is measured using a resistor having a' X% K& w0 Q1 e. Q9 p
nominal non-inductive resistance of 2 000 Ω.2 Z/ d2 z) M3 y: Z7 Y% o7 m
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Cl13.19 _! M# f* z9 u+ {/ ]0 n5 i
Protective impedance and radio interference filters are disconnected before carrying out the
/ ~$ V& |2 U0 X1 mtests.; V6 E# t. d& \8 g, _
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Protective impedance is disconnected from live parts before carrying out the tests.
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( [. I0 p: V4 U& z9 mCl22.279 L5 L c9 D+ G9 z- e
22.27 Parts connected by protective impedance shall be separated by double insulation) E2 {0 f" [6 J) u n! j5 y
or reinforced insulation.
3 g; k8 _5 N( y1 O, w& R0 O- [Compliance is checked by the tests specified for double insulation or reinforced insulation
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Cl22.379 G1 D# j; |' A: z3 o8 e
22.37 For class II appliances, capacitors shall not be connected to accessible metal parts
+ x9 \+ Y8 I2 n- k2 O$ t3 w8 eand their casings, if of metal, shall be separated from accessible metal parts by
4 z* a1 j* ~# Y0 U3 n4 ~ Msupplementary insulation.
8 t& H8 k0 S8 Q. l) GThis requirement does not apply to capacitors complying with the requirements for protective
' r: @! Q! N' h) N0 {2 @impedance specified in 22.42.
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Cl22.42
; z& G; `# C3 u3 c22.42 Protective impedance shall consist of at least two separate components whose' o3 u. n; g8 I# c) k8 B; r
impedance is unlikely to change significantly during the lifetime of the appliance. If any one of
8 D2 s) l! q) ]: W$ t' ], Hthe components is short-circuited or open-circuited the values specified in 8.1.4 shall not be
" S8 Q6 I) b9 @7 Q. q lexceeded.) a0 l/ _. s/ S9 k5 R- p0 k, b
NOTE Resistors complying with test a) of subclause 14.1 of IEC 60065 and class Y capacitors complying with, p* ^, u I i2 G" Q/ V" u7 b% t
IEC 60384-14 are considered to be components having a sufficiently stable impedance.# U4 c* E8 c3 [4 O0 O' q x8 l
Compliance is checked by inspection and by measurement.
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0 i% L9 Q% C: o' d$ i/ X$ h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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