求助：工作电压共地问题

keven2012

广东安规检测
有限公司提供：

小型摆管淋雨试验机

IPX5X6X7喷水试验机

1000L恒温恒湿箱

各种试验指现货

可程式恒温恒湿试验箱

水平垂直燃烧机

自动卷线器试验机

耐划痕试验机

各种灯头量规现货

灼热丝试验机现货

GB1002插头量规

IPX1-X7淋雨现货

IEC61347/UL935镇流器热试验箱

灯具防风罩

IK冲击试验机

UL498插头插座量规

VDE0620插头插座量规

稳定性试验台

家电温升测试角

针焰试验机现货

热电偶焊机现货

家电125mm试验指

E12灯头量规

无绳壶无绳电熨斗插拔寿命试验机

IEC60335试验指甲

工作电压测量的共地问题，次级地共N的依据来源于哪里了？

zhupinchao

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( P" [& u! }/ p* }& j3 R

浪漫罗丹

仔细阅读62368下面条款
- o( z' M! R7 J5.4.1.8 Determination of working voltage
5.4.1.8.1 General
+ g% F$ x  ^4 P, I3 \In determining working voltages, all of the following requirements apply:
4 d+ ?5 [1 F7 q6 I. k. q) }- @a) unearthed accessible conductive parts are assumed to be earthed;
b) if a transformer winding or other part is not connected to a circuit that establishes its
potential relative to earth, the winding or other part are assumed to be earthed at a point by
which the highest working voltage is obtained;
% V% S5 q1 g) l% X3 z- j* sc) except as specified in 5.4.1.6, for insulation between two transformer windings, the highest
6 q4 ^9 D1 e4 D- o; uvoltage between any two points in the two windings is the working voltage, taking into
account the voltages to which the input windings will be connected;
  C( C. G$ P+ A+ t! ^d) except as specified in 5.4.1.6, for insulation between a transformer winding and another
* x+ x( M9 D; C7 @8 ipart, the highest voltage between any point on the winding and the other part is the working
7 O( v; {) w) u6 I+ t) mvoltage;

( G  f5 c& k/ s% b% F! Ie) where double insulation is used, the working voltage across the basic insulation is
$ c( a  W1 o3 h8 b& W1 pdetermined by imagining a short-circuit across the supplementary insulation, and vice
7 U& N0 |% K: t4 o) aversa. For double insulation between transformer windings, the short-circuit is assumed
to take place at the point by which the highest working voltage is produced across the
other insulation;
f) when the working voltage is determined by measurement, the input voltage supplied to the
3 j2 p; |& W# Q/ j( Requipment shall be the rated voltage or the voltage within the rated voltage range that
$ W' v1 O6 ?- G- p/ tresults in the highest measured value;
5 U* ^% `5 a! _$ Eg) the working voltage between any point in the circuit supplied by the mains and
9 Z  x* x/ Q7 `, O% }9 ~3 }+ N– any part connected to earth; and
* v8 O; @  I  s5 n. {3 F, R– any point in a circuit isolated from the mains,
shall be taken as the greater of the following:
8 f7 M% P% a+ T8 U5 x* m– the rated voltage or the upper voltage of the rated voltage range; and
– the measured voltage;
h) when determining the working voltage for an ES1 or ES2 external circuit, the normal
operating voltages shall be taken into account. If the operating voltages are not known, the
working voltage shall be taken as the upper limits of ES1 or ES2 as applicable. Short
! B: ~# H9 z6 |7 E3 S1 H, kduration signals (such as telephone ringing) shall not be taken into account for determining
working voltage;
i) for circuits generating starting pulses (for example, discharge lamps, see 5.4.1.7), the
; k: s! y: N" J( d6 K1 a+ Xworking voltage is the peak value of the pulses with the lamp connected but before the
lamp ignites. The frequency of the working voltage to determine the minimum clearance
shall be taken as less than 30 kHz. The working voltage to determine minimum creepage
distances is the voltage measured after the ignition of the lamp.

liuqiuhong8888

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