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老师说的很对，不过A1里面对这块作了适度修正，写得更合理了，主要还是要根据两端的工作电压来判定。6 D+ I9 F& N1 `' a
When fitting Y capacitors across barriers, the dielectric strength requirement must be! L) ^7 M% _* m( }. |- T/ t! k
considered. For example, for voltages in the range of 212 V peak to 354 V peak, two MEANS* e$ ~5 ~2 P5 X- j/ y3 o
OF PATIENT PROTECTION are required to be tested at 4 000 V a.c. This would then require the
" p4 u; _) X$ i3 m* m, d* juse of Y1 capacitors. Two Y2 capacitors in series would not withstand this voltage as they are& W3 g" k/ k# L$ a1 j# k1 k* @
rated at 1 500 V a.c. each. For voltages below 212 V peak, two Y2 capacitors would suffice as* j4 I1 M2 l" x3 Q/ X( w" J
the dielectric strength requirement is 3 000 V a.c.
$ P" C$ e: d( V+ X& F! n0 t- b
: i; U3 ~; Y, {9 Y6 w$ A. yA Y capacitor (Y1 or Y2 only) complying with IEC 60384-14 is considered equivalent to one/ k' Q4 D" Q1 e4 O5 Z `$ a, ?
MEANS OF PATIENT PROTECTION. Where two capacitors are used in series, they shall be
8 _& q5 L0 ~3 f6 ]) J2 Sidentical in type (either both Y1 or both Y2) and shall have the same NOMINAL capacitance.& H2 T: H1 ~- `2 k, @( m: k' ?
The capacitor(s) shall meet the dielectric strength for the type of protection for which they are
4 V+ b( g% G- j9 }/ B0 R/ wbeing used (i.e. one or two MEANS OF PATIENT PROTECTION).
! W }% V6 x( {8 _6 E/ ?( R$ L. E: ?' x6 @
Where the working voltage across a barrier forming a MEANS OF PATIENT PROTECTION is less
: F m5 L4 r9 ]. c% Nthan 42,4 V peak a.c. or 60 V d.c., a single Y1 capacitor is acceptable for two MEANS OF
7 |% ?! B9 u) D+ b7 E MPATIENT PROTECTION. |
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发表于 2012-4-21 08:13
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