|
仔细阅读62368下面条款; |) }8 j, T0 D0 o; D
5.4.1.8 Determination of working voltage
3 [' Z; Z4 Y* {! p' t. G' y/ y5.4.1.8.1 General
. H; ^( G; b8 m! p6 t/ aIn determining working voltages, all of the following requirements apply:
$ ?" B# p |7 G; `/ {a) unearthed accessible conductive parts are assumed to be earthed;
/ U! ?: U# P5 P* a h' \! t; fb) if a transformer winding or other part is not connected to a circuit that establishes its* h7 l5 m& R- a8 h: X/ i
potential relative to earth, the winding or other part are assumed to be earthed at a point by6 c! A( d. u, V0 B0 M
which the highest working voltage is obtained;
$ M) g; D! A- C1 W9 Bc) except as specified in 5.4.1.6, for insulation between two transformer windings, the highest
/ k0 \4 i& E1 X- K7 Tvoltage between any two points in the two windings is the working voltage, taking into
# P, J. T0 r% z& P2 o3 u$ w9 f! Faccount the voltages to which the input windings will be connected;1 B5 F {, o; O7 r- ^- l4 i8 r
d) except as specified in 5.4.1.6, for insulation between a transformer winding and another
% k F4 h( r$ [* S7 l+ |; A2 {part, the highest voltage between any point on the winding and the other part is the working: \( ]6 Y0 i/ D& E2 h8 G1 `$ @/ P
voltage;
, Y _3 t2 m4 _, ]
% m3 l* m2 n" `7 o8 ue) where double insulation is used, the working voltage across the basic insulation is
8 J/ o% c+ R& [% n- fdetermined by imagining a short-circuit across the supplementary insulation, and vice
9 y" m/ a5 q' v7 v8 F1 D% tversa. For double insulation between transformer windings, the short-circuit is assumed
$ P! ~; |8 G. h% Dto take place at the point by which the highest working voltage is produced across the& _* ]' L) H8 X7 m o' d2 Z* a
other insulation;
' u) V' u4 q W' z1 If) when the working voltage is determined by measurement, the input voltage supplied to the
% `9 \; K- P& X% b1 R4 Hequipment shall be the rated voltage or the voltage within the rated voltage range that$ E4 {# k* ]! ]& f
results in the highest measured value;! n: }. w$ c& U) j6 h
g) the working voltage between any point in the circuit supplied by the mains and
# G" |: b# @8 C3 S8 D" O. `* e– any part connected to earth; and1 a, q# V$ F5 I% c" \, u
– any point in a circuit isolated from the mains,
* M0 k" Y W! r/ C! Vshall be taken as the greater of the following:& x* I, f) x- t5 Y) L8 `* L+ h$ |
– the rated voltage or the upper voltage of the rated voltage range; and
2 |5 `& C0 _$ R' [# Z– the measured voltage;
6 V0 x( w" Q. @, c* s, F. ih) when determining the working voltage for an ES1 or ES2 external circuit, the normal/ a# I, L: {0 m6 C! m8 s0 v
operating voltages shall be taken into account. If the operating voltages are not known, the4 `4 Q' R8 f9 k* S& V: w
working voltage shall be taken as the upper limits of ES1 or ES2 as applicable. Short
5 G7 r2 C8 o' iduration signals (such as telephone ringing) shall not be taken into account for determining9 d$ Y& J6 }0 J7 y
working voltage;
5 a' o9 Y) M9 B zi) for circuits generating starting pulses (for example, discharge lamps, see 5.4.1.7), the
. R- I0 }0 P4 ^working voltage is the peak value of the pulses with the lamp connected but before the
9 p+ z7 D5 c' l. q7 p* |! [lamp ignites. The frequency of the working voltage to determine the minimum clearance* V7 \3 ?0 @! G3 I! a6 u; i
shall be taken as less than 30 kHz. The working voltage to determine minimum creepage
3 n9 N! y- M& W+ R2 }3 f) g/ ^0 cdistances is the voltage measured after the ignition of the lamp. |
|