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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。
3 q3 x# `9 d& s/ g' A+ LWhen fitting Y capacitors across barriers, the dielectric strength requirement must be9 k' q7 m, F* @! ^; ~- u
considered. For example, for voltages in the range of 212 V peak to 354 V peak, two MEANS
) X. t) K# z7 H1 [/ NOF PATIENT PROTECTION are required to be tested at 4 000 V a.c. This would then require the
6 \7 B! y. m9 U$ R. Puse of Y1 capacitors. Two Y2 capacitors in series would not withstand this voltage as they are* N# f2 k8 \# A) v/ t8 z% U% ?2 g
rated at 1 500 V a.c. each. For voltages below 212 V peak, two Y2 capacitors would suffice as
6 E: J; D; }( o4 f( mthe dielectric strength requirement is 3 000 V a.c.
, l3 R, u8 ~$ r. y4 F7 s) e" c1 s, [& ~- h5 C+ k( O$ h
A Y capacitor (Y1 or Y2 only) complying with IEC 60384-14 is considered equivalent to one
# U8 X* A' g9 f* z; mMEANS OF PATIENT PROTECTION. Where two capacitors are used in series, they shall be
) ]1 R, K$ Z8 e1 w7 h) u2 xidentical in type (either both Y1 or both Y2) and shall have the same NOMINAL capacitance.
# ?/ A& V: }# x+ m9 e2 YThe capacitor(s) shall meet the dielectric strength for the type of protection for which they are4 O* M+ h2 g+ ^3 h. z3 y
being used (i.e. one or two MEANS OF PATIENT PROTECTION).- z6 [$ V4 r1 G0 O: p
- K0 P( C/ J; Q Q; a9 XWhere the working voltage across a barrier forming a MEANS OF PATIENT PROTECTION is less
1 ]( B% a ~9 W2 Ithan 42,4 V peak a.c. or 60 V d.c., a single Y1 capacitor is acceptable for two MEANS OF5 L# w# M: i# a/ @; v+ O
PATIENT PROTECTION. |
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发表于 2012-4-21 08:13
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