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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。1 _& e2 ], y E7 r3 U! U) n
When fitting Y capacitors across barriers, the dielectric strength requirement must be
F; x2 f3 z# q4 I2 m3 rconsidered. For example, for voltages in the range of 212 V peak to 354 V peak, two MEANS8 }0 b3 u7 h3 r3 P& I& a1 D! u9 o
OF PATIENT PROTECTION are required to be tested at 4 000 V a.c. This would then require the4 `$ r, @7 h3 v" F2 `, m
use of Y1 capacitors. Two Y2 capacitors in series would not withstand this voltage as they are7 z. t4 @0 g# o4 `0 s2 E" W
rated at 1 500 V a.c. each. For voltages below 212 V peak, two Y2 capacitors would suffice as" n5 j$ ~& g3 y% u# i7 J4 Z
the dielectric strength requirement is 3 000 V a.c.
/ y/ M) k/ [* A! O w5 W. v' }
5 b; n/ N- W( l' HA Y capacitor (Y1 or Y2 only) complying with IEC 60384-14 is considered equivalent to one
~9 s! ]; S1 F9 z iMEANS OF PATIENT PROTECTION. Where two capacitors are used in series, they shall be# `3 Z7 F" p2 r Z; `
identical in type (either both Y1 or both Y2) and shall have the same NOMINAL capacitance.
# W) W* ~ C( WThe capacitor(s) shall meet the dielectric strength for the type of protection for which they are
+ w) h/ b* u& Jbeing used (i.e. one or two MEANS OF PATIENT PROTECTION).4 B. a; R$ p& u' n/ p4 e
3 ]# \ V6 k- C1 O* {: Q3 H- t x' ]
Where the working voltage across a barrier forming a MEANS OF PATIENT PROTECTION is less# n% E0 s9 z" z! u& R! t5 v
than 42,4 V peak a.c. or 60 V d.c., a single Y1 capacitor is acceptable for two MEANS OF+ R8 i J7 A( L \& d+ N8 `- B8 {
PATIENT PROTECTION. |
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发表于 2012-4-21 08:13
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