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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浪漫罗丹

仔细阅读62368下面条款
6 p# g4 H) w0 |: w5.4.1.8 Determination of working voltage
- e/ ^! v9 T+ `$ Y5.4.1.8.1 General
2 ^! f; p" y# YIn determining working voltages, all of the following requirements apply:
- _0 D! \$ Z8 S3 P7 F6 @% q8 E% la) unearthed accessible conductive parts are assumed to be earthed;
4 B0 g4 Q; P" y0 B+ C- vb) if a transformer winding or other part is not connected to a circuit that establishes its
! Q5 w0 h: V6 Y6 E- P/ T# mpotential relative to earth, the winding or other part are assumed to be earthed at a point by
which the highest working voltage is obtained;
c) except as specified in 5.4.1.6, for insulation between two transformer windings, the highest
5 I1 T; H( N- l- g7 Tvoltage 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;
d) except as specified in 5.4.1.6, for insulation between a transformer winding and another
) Q: r2 c  A2 }) Q& R5 E4 J1 N7 R% Npart, the highest voltage between any point on the winding and the other part is the working
- P0 y5 A3 Y! q. Tvoltage;
: E$ b& k7 k" h
2 z5 g/ r- G* S$ \. f. u( l8 {e) where double insulation is used, the working voltage across the basic insulation is
determined by imagining a short-circuit across the supplementary insulation, and vice
versa. 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
* W) J- O/ a+ o0 F6 t( Lequipment shall be the rated voltage or the voltage within the rated voltage range that
results in the highest measured value;
$ S$ w5 B7 }# ]2 A( I( m# U6 pg) the working voltage between any point in the circuit supplied by the mains and
– any part connected to earth; and
– any point in a circuit isolated from the mains,
$ C7 [+ x' {9 ?% Sshall be taken as the greater of the following:
- s! o3 m4 L9 `4 F2 L# Y. f0 ^– 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
& L9 P& k# |- I( d* D0 {working voltage shall be taken as the upper limits of ES1 or ES2 as applicable. Short
& V3 O5 R: d7 ?3 R: L, aduration signals (such as telephone ringing) shall not be taken into account for determining
9 r9 y8 q! }1 s# hworking voltage;
! c* j7 P+ K, \- K" Y& x1 f  Z+ k$ \i) for circuits generating starting pulses (for example, discharge lamps, see 5.4.1.7), the
4 `9 F1 Y* D; i6 h" |3 [6 h3 _working 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
/ z6 {& C, g" m) C5 oshall 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.

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