求助：工作电压共地问题

keven2012

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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

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IEC61347/UL935镇流器热试验箱

灯具防风罩

IK冲击试验机

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针焰试验机现货

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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？
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" _) p& {6 I: ~+ S' l# v

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浪漫罗丹

仔细阅读62368下面条款
5.4.1.8 Determination of working voltage
5.4.1.8.1 General
. h7 p6 E' o" g1 VIn determining working voltages, all of the following requirements apply:
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
; `. O  s- e5 L' B0 O' K; Tpotential relative to earth, the winding or other part are assumed to be earthed at a point by
+ Z. J) b- r/ k# uwhich the highest working voltage is obtained;
  G( l! _/ E: p$ w; R& tc) except as specified in 5.4.1.6, for insulation between two transformer windings, the highest
voltage between any two points in the two windings is the working voltage, taking into
4 I& M$ H9 L. o* n$ {$ K4 ~( Yaccount the voltages to which the input windings will be connected;
4 G% c4 W( d) _$ [1 j' ]3 B7 ld) except as specified in 5.4.1.6, for insulation between a transformer winding and another
* Y- D' S6 ~# V/ {/ Jpart, the highest voltage between any point on the winding and the other part is the working
voltage;
( C1 f- O, K; d- R# _* A
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
- G  M2 k& }  m% J0 p  R- Vversa. For double insulation between transformer windings, the short-circuit is assumed
! G: u* W# }! `5 u5 x  Jto take place at the point by which the highest working voltage is produced across the
/ K9 v* @) Z1 D9 |; L% nother insulation;
f) when the working voltage is determined by measurement, the input voltage supplied to the
$ |1 L6 \7 a: C+ S- ?: Eequipment shall be the rated voltage or the voltage within the rated voltage range that
results in the highest measured value;
g) 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,
shall be taken as the greater of the following:
- H5 l4 C, F1 u% _: z0 g+ ~– 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
; G" |' a/ P6 iworking voltage shall be taken as the upper limits of ES1 or ES2 as applicable. Short
6 @3 D1 j. S" X* v' P6 [duration signals (such as telephone ringing) shall not be taken into account for determining
; {* P7 N: b4 ]* Xworking voltage;
) R; O, i$ Y6 d% f9 F1 U  H1 c$ fi) for circuits generating starting pulses (for example, discharge lamps, see 5.4.1.7), the
3 E' Y2 @" B! A4 t4 Yworking voltage is the peak value of the pulses with the lamp connected but before the
0 h1 Q; W/ G' Q# A; _, R  Rlamp 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
5 s0 t1 d- d% @# F5 ndistances is the voltage measured after the ignition of the lamp.

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