安规网

标题: DSH 432 Protective Impedance versus no-load voltage [打印本页]
作者: 小米    时间: 2012-11-5 10:22
标题: DSH 432 Protective Impedance versus no-load voltage
DSH 4328 l# c% Y( w2 E0 e
( V$ T5 \( o: a9 Y3 Y" Q2 ^
Protective Impedance versus no-load voltage- l6 ^& N2 D( _& u
18f)8 ?+ n& E( C) G& f9 Y
60601-1(ed.2);am1;am2# L! [% b) ^+ W" |( ?

( y) Q- {! s5 A: d) A" \Standard(s)- (year and edition):
- |# d2 z) n2 N# X7 v) `4 s* M3 mIEC 60601-1:1988 Ed.2 Am1+Am21 r1 h0 p; |9 ?4 p
Sub clause(s): 18f)& m" c1 q8 l3 k# d
Sheet n°: DSH-432
" _3 I" P* O6 X$ USubject: Protective Impedance versus noload voltage
8 d0 S% T6 h0 ]Key words: Protective, impedance, earth, connection, no-load& q  ]9 Q" j; v5 v' @8 b
Confirmed by CTL at its 39th meeting, in Cologne
* A  |5 t0 @7 HQuestion:0 a. B  c: [" l% a2 u* X
EQUIPMENT for example having a rated current of 30 A require a test current of 1.5 times 30 A.5 x% f* w8 Y0 L+ N
With a maximum impedance of 0.2 W the voltage drop has to be 9 V (0.2 W * 45 A = 9 V). This is# y" E% Z+ N, J3 i3 X2 i" w
in contradiction to the required no-load voltage of 6 V maximum.! ~5 }! q& `( T$ {
Decision:5 O% x. X- c+ B/ e  E
Measuring the protective earth connection has in fact two reasons. It is to determine impedance: G' `4 [( v# H
and cross-sectional area of protective earth connections. For a measuring current of 25 A both
* s3 `6 _$ U7 D2 d% pcan be done with one measurement. Requiring a measuring current of more than 25 A it shall be$ F0 L" b+ ]% z1 m
splitted up into two measurements. In this case, the impedance shall be determined first, using a
) {7 b  F( w9 ^% E7 ^( ]3 Tvoltage not exceeding 6 V.: R- c( L2 a$ Y6 i
If cross-sectional area of the protective earth connections cannot be determined as equal to the
; _% W9 [* z: h" A# C  Yone for the phase by measurement of the area, then measurement with current shall be from a
- _3 z9 I  S+ b( l& w! b8 S+ `source with a higher voltage than 6 V.
/ ^' q' k9 K/ g- w6 c, {9 K+ q
4 }( ^4 s! T' }, b: i$ K[attach]77075[/attach]
( x7 R3 o: s; ^- Q5 @9 ~



欢迎光临 安规网 (http://bbs1.angui.org/) Powered by Discuz! X3.2