|
|
|  DSH 432
- y$ O9 u! I( h; x! W4 }& N" G A W
| Protective Impedance versus no-load voltage. t/ ?5 J6 q7 d" {$ j
| 18f)& q! o) K- d* l# R: D0 \, X3 R
| 60601-1(ed.2);am1;am26 b) K/ k' A! o! z
|
2 l6 R& H5 @! S' X* K) d( y: O8 aStandard(s)- (year and edition): N* A! R! ?0 s* q3 J
IEC 60601-1:1988 Ed.2 Am1+Am2* M: r$ R4 y. v8 Y( v5 B
Sub clause(s): 18f)
3 K; s6 P( w, l* L& t' w/ XSheet n°: DSH-432
" N |5 Y+ F7 O# C ASubject: Protective Impedance versus noload voltage
) q9 V' G2 O4 ^Key words: Protective, impedance, earth, connection, no-load. `6 f3 [ e# P
Confirmed by CTL at its 39th meeting, in Cologne* |6 \/ U4 F& H: |
Question:
6 o# ^ C7 c8 P) D1 V& E" G/ GEQUIPMENT for example having a rated current of 30 A require a test current of 1.5 times 30 A.% B% z7 q4 }5 W1 d, o* [
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. {+ j* E, y* N( u+ @
in contradiction to the required no-load voltage of 6 V maximum.# q$ a- m; w4 b: z' L6 {
Decision:
X& Y5 z7 i! J( |/ s, E UMeasuring the protective earth connection has in fact two reasons. It is to determine impedance$ ]# L+ Q L% z/ w# p
and cross-sectional area of protective earth connections. For a measuring current of 25 A both" S K% P2 u9 y' v
can be done with one measurement. Requiring a measuring current of more than 25 A it shall be
: f4 W' }" s: Msplitted up into two measurements. In this case, the impedance shall be determined first, using a
3 y. e3 R( v; j+ Evoltage not exceeding 6 V.1 _" V: O. t$ M: j4 h9 e- T
If cross-sectional area of the protective earth connections cannot be determined as equal to the
" P1 R2 p7 b r- Y2 |! f* _one for the phase by measurement of the area, then measurement with current shall be from a
b8 c0 A' u% ~' Rsource with a higher voltage than 6 V., K5 ?! Y% r; [6 M! V' u
( F2 T& B/ |" Z# V/ J+ ]! K7 O7 [; x
|
本帖子中包含更多资源
您需要 登录 才可以下载或查看，没有帐号？注册安规
x
|
/1 
|关于安规|小黑屋|安规QQ群|Archiver|手机版|安规网
( 粤ICP13023453-10 ) 
窥视卡
雷达卡
发表于 2012-11-5 10:22
收藏
分享
好帖
鸡蛋
提升卡
置顶卡
沉默卡
喧嚣卡
变色卡
抢沙发
千斤顶
显身卡