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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。, f( L$ x& B/ T5 v3 ^
When fitting Y capacitors across barriers, the dielectric strength requirement must be* A* u& a ~/ F5 |# _- }1 o3 ^
considered. For example, for voltages in the range of 212 V peak to 354 V peak, two MEANS( h: i5 b7 b/ Y
OF PATIENT PROTECTION are required to be tested at 4 000 V a.c. This would then require the/ }' M3 N! s4 ^: {1 y
use of Y1 capacitors. Two Y2 capacitors in series would not withstand this voltage as they are7 x' O+ F# j2 k
rated at 1 500 V a.c. each. For voltages below 212 V peak, two Y2 capacitors would suffice as
+ \5 j+ D, X2 L* X# I: w' xthe dielectric strength requirement is 3 000 V a.c.
; @( D0 T" g) K; N( [
: g8 f; `" e4 y0 P; p% `& L" vA Y capacitor (Y1 or Y2 only) complying with IEC 60384-14 is considered equivalent to one
G. p: v5 Q" q) e6 q7 v4 |& yMEANS OF PATIENT PROTECTION. Where two capacitors are used in series, they shall be
2 `$ ^/ U' K+ L) f% ~* iidentical in type (either both Y1 or both Y2) and shall have the same NOMINAL capacitance.
! `% V1 I8 {6 q; T6 u( BThe capacitor(s) shall meet the dielectric strength for the type of protection for which they are. O3 B( ~+ w+ L. d# |9 r& M
being used (i.e. one or two MEANS OF PATIENT PROTECTION).4 Q' S2 d. n# l6 b' q+ L
& S3 i' ~% S* g- b2 ]6 v3 X. N6 p! {Where the working voltage across a barrier forming a MEANS OF PATIENT PROTECTION is less
5 r4 w3 S' j/ x: U7 B6 H& Sthan 42,4 V peak a.c. or 60 V d.c., a single Y1 capacitor is acceptable for two MEANS OF2 w9 x: O0 G3 [% {
PATIENT PROTECTION. |
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发表于 2012-4-21 08:13
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