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标题: IEC 60601(1995) 18.f)保护接地阻抗测量的问题点？ [打印本页]
作者: shadow    时间: 2009-4-1 14:11
标题: IEC 60601(1995) 18.f)保护接地阻抗测量的问题点？
]① 标准中要求“用空载电压不超过6V，频率为50 Hz或60 Hz的电流源”，" ]$ P& z) |4 V6 w/ V) c
如果测量结果是“在流经额定电流的1.5倍的试验电流时，当其电流与阻抗的积超过６Ｖ时”，与标准要求的情况不符合，这种情况下，通常怎么解决？1 O. \; _. W5 Y) h& j) n5 C- b3 ^1 K
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②IEC 60601-1(2005) 8.6.4 "Where the product of the test current as specified above and the total impedance (i.e. the impedance being measured plus the impedance of the test leads and the contact impedances) would exceed 6 V, the impedance is first measured with a no-load voltage not
1 F! Z. T# ^9 W/ a0 y/ c. w7 }$ Cexceeding 6 V.,6 x* q2 K/ w. c* A" Z& J
标准中要求“上述电流与合计阻抗（正在测定的阻抗和测量导线的阻抗和接触阻抗的和）的积，超过6V时，测量最初未超过6V的空载电压下的阻抗。”，那么如何测量最初空载电压未超过6V时的保护接地阻抗？
作者: nesta    时间: 2009-4-1 20:24
引用第0楼shadow于2009-04-01 14:11发表的 IEC 60601(1995) 18.f)保护接地阻抗测量的问题点？ :
3 u6 N7 L) s' U# j8 J" w]① 标准中要求“用空载电压不超过6V，频率为50 Hz或60 Hz的电流源”，
+ c& R9 R& @8 m/ d7 v2 b6 u6 B如果测量结果是“在流经额定电流的1.5倍的试验电流时，当其电流与阻抗的积超过６Ｖ时”，与标准要求的情况不符合，这种情况下，通常怎么解决？3 C0 O% U3 `$ O) E) M  H$ i
2 g/ h8 B3 i2 t- D6 u" r! Y# H; D. B
②IEC 60601-1(2005) 8.6.4 "Where the product of the test current as specified above and the total impedance (i.e. the impedance being measured plus the impedance of the test leads and the contact impedances) would exceed 6 V, the impedance is first measured with a no-load voltage not
+ Z# ]% r+ S+ K% q/ A% Zexceeding 6 V.,
( J2 g/ t8 U- Z' G0 p.......

+ \, A9 |/ ]0 b3 V: _. {# {7 f" _$ ~  z7 V8 J
你可以看看第二版的ctl决议，里面有说明
作者: painkillor    时间: 2009-4-1 21:48
嗯。CTL432决议，<6V确定其电阻，再额定电流1.5倍测试其横截面积。
作者: shadow    时间: 2009-4-2 09:48
CTL432决议的具体内容在哪里能看到呢？
作者: 316979109    时间: 2009-4-2 11:00
Decision:
/ _: N) i  W; ?8 ^Measuring the protective earth connection has in fact two reasons. It is to determine impedance$ ]* z8 }1 Q2 @4 i; i3 M
and cross-sectional area of protective earth connections. For a measuring current of 25 A both' w' e. w5 k; H' E7 c
can be done with one measurement. Requiring a measuring current of more than 25 A it shall be
; |3 s1 q, F  z" N; M& Vsplitted up into two measurements. In this case, the impedance shall be determined first, using a, C" s: g" n- ?3 D
voltage not exceeding 6 V.
8 K; P; H* E/ r! f6 E1 jIf cross-sectional area of the protective earth connections cannot be determined as equal to the
0 n" E  t4 q9 ?% E; a4 g* {one for the phase by measurement of the area, then measurement with current shall be from a  c4 d1 {3 j3 o% c2 g4 ?4 D5 d
source with a higher voltage than 6 V.* q0 r) W6 m. _: y/ ]
Explanatory notes:+ u. w7 }  G. I! e
A circuit to the PROTECTIVE EARTH TERMINAL may have zones of higher impedance, for
% _! _( t+ }9 y5 Z. zexample due to oxidation of materials. Voltages higher than 6 V prevent detection of such zones% o# L: y& ^8 z& E' t
because of their ability to flash through. In this case, the impedance shall be determined first,4 b. n% ]5 W( z3 p
using a voltage not exceeding 6 V.
( e) X$ S- a2 X6 bUsing low voltages and low currents has a great impact on the accuracy of the measurement of" n1 Z& x) c3 t1 |
low impedances. Impedances in the range of 0.1 W and 0.2 W then require a sophisticated7 e3 t# Z8 z, w
measuring device.
, S0 k5 q: P5 L& W/ R* q# `: QThe relation between rated current of the EQUIPMENT and measuring current is because to0 f( W2 H- i/ B2 W4 \
check cross-sectional areas of protective earth connections. If parts of the construction or printed- {  D& e3 E9 s4 `
circuit boards are used for protective earth connections the cross-sectional areas and the ability/ C7 G/ |9 ~2 |
of carrying short circuit c urrents are in doubt.



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