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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。
' U, _- r5 D8 N- [; tWhen fitting Y capacitors across barriers, the dielectric strength requirement must be& Z. _5 u3 H) M$ D0 I2 |
considered. For example, for voltages in the range of 212 V peak to 354 V peak, two MEANS1 O, r' G' W) M" `3 f
OF PATIENT PROTECTION are required to be tested at 4 000 V a.c. This would then require the% H; v, g" j9 p; K8 B# d. j# {* H
use of Y1 capacitors. Two Y2 capacitors in series would not withstand this voltage as they are
1 l2 z6 U1 b A p6 y/ frated at 1 500 V a.c. each. For voltages below 212 V peak, two Y2 capacitors would suffice as% H2 U, A$ ^4 ~$ K6 d4 z; R
the dielectric strength requirement is 3 000 V a.c.
+ ^& V" F1 y% o, n, g
1 U% y3 w9 c# p: q9 oA Y capacitor (Y1 or Y2 only) complying with IEC 60384-14 is considered equivalent to one
. W$ }( R, Y9 a$ k9 B6 ^MEANS OF PATIENT PROTECTION. Where two capacitors are used in series, they shall be
& a0 q) b, k9 e+ u7 g* f; ?& _- ridentical in type (either both Y1 or both Y2) and shall have the same NOMINAL capacitance.- d5 i3 A. A! y" m6 x
The capacitor(s) shall meet the dielectric strength for the type of protection for which they are
; [7 H6 n: z5 Q, _/ B fbeing used (i.e. one or two MEANS OF PATIENT PROTECTION).
/ D9 x0 F7 A r6 o8 I2 H% Q. l2 V. ]& u# w4 j4 O% p
Where the working voltage across a barrier forming a MEANS OF PATIENT PROTECTION is less
/ b$ E0 p/ ~' M" K" Y2 i$ J7 f- tthan 42,4 V peak a.c. or 60 V d.c., a single Y1 capacitor is acceptable for two MEANS OF- r7 ~. w+ D( V5 f- W9 Q( @
PATIENT PROTECTION. |
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