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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 a) e! M! D$ b, z1 E# R( M/ G
When fitting Y capacitors across barriers, the dielectric strength requirement must be( H h$ Y/ ~% a! y
considered. For example, for voltages in the range of 212 V peak to 354 V peak, two MEANS
0 H2 b6 Z7 l5 G) X) ?! lOF PATIENT PROTECTION are required to be tested at 4 000 V a.c. This would then require the1 f- V: b3 u) d* _) k9 c
use of Y1 capacitors. Two Y2 capacitors in series would not withstand this voltage as they are5 T U ~. K w, ?
rated at 1 500 V a.c. each. For voltages below 212 V peak, two Y2 capacitors would suffice as
: R f% e# I% h _8 Mthe dielectric strength requirement is 3 000 V a.c.
" R2 r% v C% Y' L/ m ~ G% g, j; P+ m8 s" o7 P2 n1 \
A Y capacitor (Y1 or Y2 only) complying with IEC 60384-14 is considered equivalent to one3 l, ^' C5 j2 P/ k
MEANS OF PATIENT PROTECTION. Where two capacitors are used in series, they shall be5 k7 l- y4 W( M4 b7 r
identical in type (either both Y1 or both Y2) and shall have the same NOMINAL capacitance.
4 W+ I! f( L' [9 ]' `' zThe capacitor(s) shall meet the dielectric strength for the type of protection for which they are! g2 x- C W1 x: a! A' L7 I
being used (i.e. one or two MEANS OF PATIENT PROTECTION).7 c. D7 l7 H6 L! D
' ^ h; B9 J0 A/ \) U+ eWhere the working voltage across a barrier forming a MEANS OF PATIENT PROTECTION is less
7 Z& R: |! J3 `1 }% athan 42,4 V peak a.c. or 60 V d.c., a single Y1 capacitor is acceptable for two MEANS OF
3 t. U3 ?6 [9 y4 ^" Z" iPATIENT PROTECTION. |
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发表于 2012-4-21 08:13
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