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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。 t9 Z, B3 S6 _ k0 J3 F+ o1 K. i
When fitting Y capacitors across barriers, the dielectric strength requirement must be/ O3 e8 n! c1 j( {7 T5 w
considered. For example, for voltages in the range of 212 V peak to 354 V peak, two MEANS4 |( { U( f f
OF PATIENT PROTECTION are required to be tested at 4 000 V a.c. This would then require the
3 r0 _3 Z& H/ x& g1 ^; Uuse of Y1 capacitors. Two Y2 capacitors in series would not withstand this voltage as they are9 |& b7 P7 o1 F( L2 a; Y
rated at 1 500 V a.c. each. For voltages below 212 V peak, two Y2 capacitors would suffice as3 v {2 o9 [( i& E& H* J( x) l
the dielectric strength requirement is 3 000 V a.c./ z# r& Q' `% x
$ J- {$ S M9 XA Y capacitor (Y1 or Y2 only) complying with IEC 60384-14 is considered equivalent to one8 g/ l* m" r+ P
MEANS OF PATIENT PROTECTION. Where two capacitors are used in series, they shall be
/ R3 P2 | I( p3 g7 h- E1 |identical in type (either both Y1 or both Y2) and shall have the same NOMINAL capacitance.
8 S( _8 ?5 Y! w' R& p! XThe capacitor(s) shall meet the dielectric strength for the type of protection for which they are( P+ Y3 e2 s# H- ]8 I, |. o s8 y
being used (i.e. one or two MEANS OF PATIENT PROTECTION).
- I5 w1 n: Z% z( Q; o4 o% b8 p7 @. j. L- [- S' P; i. l
Where the working voltage across a barrier forming a MEANS OF PATIENT PROTECTION is less8 R# F1 W7 h- Y9 K1 M
than 42,4 V peak a.c. or 60 V d.c., a single Y1 capacitor is acceptable for two MEANS OF
% N; w8 ]6 ^- U hPATIENT PROTECTION. |
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发表于 2012-4-21 08:13
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