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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。6 v6 K4 t. Z# c, ^& O
When fitting Y capacitors across barriers, the dielectric strength requirement must be" I' Y$ Q$ F8 y; A
considered. For example, for voltages in the range of 212 V peak to 354 V peak, two MEANS4 }3 K k/ s8 p$ O
OF PATIENT PROTECTION are required to be tested at 4 000 V a.c. This would then require the, N# Z# L; i6 E$ `, ]3 U0 `6 j i
use of Y1 capacitors. Two Y2 capacitors in series would not withstand this voltage as they are. }& ?5 {5 E5 o* l$ w% y0 ]
rated at 1 500 V a.c. each. For voltages below 212 V peak, two Y2 capacitors would suffice as4 n1 t; V% x. E; S( I
the dielectric strength requirement is 3 000 V a.c.
* h1 `$ M0 B4 b) |: p& W9 ~
: z1 R+ h8 E9 {% Z. u5 \1 }& M, xA Y capacitor (Y1 or Y2 only) complying with IEC 60384-14 is considered equivalent to one% \- d! Y* B/ }. p. X
MEANS OF PATIENT PROTECTION. Where two capacitors are used in series, they shall be
+ U+ e, E8 j. v% r( qidentical in type (either both Y1 or both Y2) and shall have the same NOMINAL capacitance.
7 F* A- o) {# J6 Y4 j4 A9 Z; o C) R4 j& i' wThe capacitor(s) shall meet the dielectric strength for the type of protection for which they are
- T- R/ s- h5 A5 d$ R1 X, A6 zbeing used (i.e. one or two MEANS OF PATIENT PROTECTION).6 N3 d9 |" o) {/ J( U/ p
/ l; U) p4 w" ~0 C+ H, Y
Where the working voltage across a barrier forming a MEANS OF PATIENT PROTECTION is less; u/ r) q+ b& d8 I
than 42,4 V peak a.c. or 60 V d.c., a single Y1 capacitor is acceptable for two MEANS OF3 w. D$ @1 j# u% u, I( Z; l$ G2 @
PATIENT PROTECTION. |
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发表于 2012-4-21 08:13
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