求助：工作电压共地问题

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IEC60335试验指甲

7 g  p$ v7 l  J! a# i) T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？

) W# P2 x7 q6 _

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仔细阅读62368下面条款
5.4.1.8 Determination of working voltage
6 Z4 @3 \6 X( ]% V  s5 \5.4.1.8.1 General
In determining working voltages, all of the following requirements apply:
" }& f' ?7 X! z( ]- W8 qa) 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;
" j! n6 C3 Z0 v/ {3 r" k# d, mc) except as specified in 5.4.1.6, for insulation between two transformer windings, the highest
# C% j/ F" l' Z( ]; Hvoltage 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;
- W% s1 g8 T/ W, \7 x5 H$ od) except as specified in 5.4.1.6, for insulation between a transformer winding and another
part, the highest voltage between any point on the winding and the other part is the working
4 S. \" V' f+ r2 g" @$ h' mvoltage;

e) where double insulation is used, the working voltage across the basic insulation is
) s7 n; |/ _3 ]1 @# @determined by imagining a short-circuit across the supplementary insulation, and vice
! d9 E' c, ], u, G+ G. H9 Gversa. 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;
9 o7 W3 _8 S7 A& B8 z5 a  if) when the working voltage is determined by measurement, the input voltage supplied to the
) H$ k0 Y- a0 Iequipment shall be the rated voltage or the voltage within the rated voltage range that
results in the highest measured value;
1 G7 \/ I3 T' X+ X! |) vg) the working voltage between any point in the circuit supplied by the mains and
– any part connected to earth; and
, k+ r2 ^( \+ N& _+ ~: M, \" E3 m– any point in a circuit isolated from the mains,
& a7 `8 m9 u! T# Dshall be taken as the greater of the following:
: Y4 h& r# h) u  g/ l' M– the rated voltage or the upper voltage of the rated voltage range; and
– the measured voltage;
* T. @! o+ `7 C5 Q9 M% c, kh) when determining the working voltage for an ES1 or ES2 external circuit, the normal
9 L* n' l% ~* W3 u$ a8 |* M  _operating voltages shall be taken into account. If the operating voltages are not known, the
, {) o" X  C% t- e" T0 b7 @working voltage shall be taken as the upper limits of ES1 or ES2 as applicable. Short
duration signals (such as telephone ringing) shall not be taken into account for determining
" l3 R2 O, g( y- }working voltage;
i) for circuits generating starting pulses (for example, discharge lamps, see 5.4.1.7), the
3 U4 W7 Y6 q4 c# D* L3 S; eworking voltage is the peak value of the pulses with the lamp connected but before the
3 ~5 t# F, {& n% `% M& h! _3 D) F8 @lamp ignites. The frequency of the working voltage to determine the minimum clearance
2 ?1 _* t, p6 Yshall be taken as less than 30 kHz. The working voltage to determine minimum creepage
3 N/ K" Q: U/ Q$ R+ G; D# xdistances is the voltage measured after the ignition of the lamp.

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