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仔细阅读62368下面条款6 }5 t1 {" m6 o7 K
5.4.1.8 Determination of working voltage
1 y$ p; Y) G& S8 e3 ?$ J5.4.1.8.1 General
1 P& N3 U$ f: t Z0 U; g! d7 `In determining working voltages, all of the following requirements apply:: T) L7 J* i& H, ?, c
a) unearthed accessible conductive parts are assumed to be earthed;
2 L! m+ p: q- [0 h% v/ \( J; ]3 T7 H- Eb) if a transformer winding or other part is not connected to a circuit that establishes its5 V2 J% j4 Y+ T; f# G8 [) n
potential relative to earth, the winding or other part are assumed to be earthed at a point by" [# m! f7 @) V4 x/ R9 t4 E. e
which the highest working voltage is obtained;
: G5 X- q, ^) I0 Nc) except as specified in 5.4.1.6, for insulation between two transformer windings, the highest8 ~. k5 Y, ]6 u6 v; D" u
voltage between any two points in the two windings is the working voltage, taking into4 H$ k' C1 v+ P, c! W# U
account the voltages to which the input windings will be connected;5 K' W+ \) }6 w
d) except as specified in 5.4.1.6, for insulation between a transformer winding and another5 A9 s. `% O7 o& J3 K/ ]
part, the highest voltage between any point on the winding and the other part is the working0 U4 B5 ]$ Z& N( O s$ K3 Y
voltage;
9 {( [# r2 K+ J" E
5 _# q2 u2 Q8 `6 `; P* he) where double insulation is used, the working voltage across the basic insulation is
" F- T! ?1 F) e+ X0 z# bdetermined by imagining a short-circuit across the supplementary insulation, and vice; I x) ~$ |1 \5 T& R, e. C
versa. For double insulation between transformer windings, the short-circuit is assumed
# e$ I- g% a8 L3 v0 f9 U4 T" \to take place at the point by which the highest working voltage is produced across the; o0 k3 W* i7 ]% c2 w6 @" F- \; X
other insulation;9 {# ?# y H- A7 B4 }% D1 Z9 `
f) when the working voltage is determined by measurement, the input voltage supplied to the
! f. ^3 y1 D9 P+ m& q# U; A: K0 c0 jequipment shall be the rated voltage or the voltage within the rated voltage range that: F" U. ?; z8 p1 M; P( Y
results in the highest measured value;8 w; e ?7 H8 M: S' o' _5 ?' O& A
g) the working voltage between any point in the circuit supplied by the mains and0 [" N6 R/ H; |3 Q
– any part connected to earth; and
' V3 M7 d1 D1 \* f6 d9 }* d– any point in a circuit isolated from the mains,
9 D/ }8 x' [" j7 }shall be taken as the greater of the following:5 ^5 p$ S1 H+ U' t1 Z t
– the rated voltage or the upper voltage of the rated voltage range; and8 @. a6 n1 O9 f/ s% J+ u
– the measured voltage;" B5 Q0 I* V* u1 O: N/ w
h) when determining the working voltage for an ES1 or ES2 external circuit, the normal
$ O6 B% a+ {- Q3 M7 Q9 s+ c0 ] ~operating voltages shall be taken into account. If the operating voltages are not known, the
" q. \2 N, W, {' g- hworking voltage shall be taken as the upper limits of ES1 or ES2 as applicable. Short( u- [* c) I; N! @7 V
duration signals (such as telephone ringing) shall not be taken into account for determining9 R( N, i; j" F0 q9 R
working voltage;! W% i0 @4 v# N/ `
i) for circuits generating starting pulses (for example, discharge lamps, see 5.4.1.7), the1 k4 s# G% h' p* m) k; E8 Q
working voltage is the peak value of the pulses with the lamp connected but before the
) H3 b3 o& Y( X# zlamp ignites. The frequency of the working voltage to determine the minimum clearance
7 p% J+ R3 z( O. e1 }+ W! zshall be taken as less than 30 kHz. The working voltage to determine minimum creepage
5 u1 O. ?; Y! ddistances is the voltage measured after the ignition of the lamp. |
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