|
5.1 Spark test after insulating
: N" P7 g: R" {7 a) h2 |3 k/ u2 k
% H k; M# {3 q5 e: A; zThe voltage source of a dc or ac spark tester shall maintain the following test voltage under all nor
; l" t% A8 L2 s) v4 l. N
% Y7 _+ W. N) v( \3 T/ U2 Emal conditions of leakage current:
7 g' ]8 {" \4 h2 l1 T; t& g0 X+ p* `2 w6 n' Y4 ^- E0 }
a) An essentially sinusoidal rms potential of 1750 V for an ac test; . b; ]4 J, l5 B# J
$ K. q0 F( Q8 A6 L" Nb) 2500 V for a dc test. The current output of which the dc power supply is capable shall not exceed0 r( n {9 t8 @# p8 p. z5 `
- D4 a* X/ ?) P5 D: I$ T% f3 J9 I 5 mA. Any ripple shall not exceed 1 per cent. After a fault, the dc test voltage shall recover to the full
6 A1 T4 F! M+ O" O" g+ j) }" W; X+ t5 R: ~5 S- V9 H
test voltage in 5 ms or less, unless 610 mm (2 ft) or less of the product travels through the electrode
, M' v9 ^$ l0 N2 A" t/ xe in the time that it takes for the full voltage recovery;
: e8 e5 G) a+ {* d. g% w1 m8 e) H! o
c) For conductor gauge sizes 22 – 30 AWG which are to be used in cables without coaxial membe
U0 G5 U8 H( a; h& G& H' w2 Y4 A/ m' q/ }& L
rs but with foam or foam skin insulation and protected by bonded metal shields, the following spar
7 H# G4 T8 G/ e4 H, `8 \9 \& S* G4 _" b4 Q/ q+ y- I
k test voltage may be used: - s2 m5 G# R8 X+ v0 ?4 @' d
Conductor size Test Voltage ) C8 ?) o% n- b' l: }! s5 o8 E
22, 23 AWG 1500 V dc or 1050 V ac
6 e J1 ^, C, ~$ o7 k% y' \ 24, 25 AWG 1200 V dc or 850 V ac & a( A- M' d2 i, f
26–30AWG 1000Vdcor750Vac - O8 x+ [: c2 o5 K0 N
: t% C# y4 P% Z* w' A; md) For cables without bonded metal shields, and with foam insulation that is not more than 0.20 m
' X" J- g/ b) a) Q" Z0 _: ^ B$ U: y9 O, l2 d0 h3 M6 C" X
m (0.008 in) in average thickness and does not have a skin, the spark test voltage may be reduced! }. c, `- x8 j3 Z+ F
1 S' A* s3 ]% a& L% j4 |; y# R
to 1250 V ac or 1750 V dc, provided that the dielectric strength test voltage required by Clause
" X1 W; v5 w" \ f. f- l
* q! P, L- x" S& H6 x2 H5.3.5 is met.
4 W! K1 z+ j$ H! B 6 E* l3 l$ y- u7 T* ]
这段内容看得有点糊涂,前辈们可否指导一下?2 W8 f- U* Y5 n7 }% w( o
问题1. 首先我不理解d)中所涉及的skin在实物中是什么?! H' ?% I' \3 m/ _4 y: b: ?
问题2. c)中foam 和foam skin 有何区别?
8 E- c6 `8 I+ V8 v我想先把这个问题搞清楚了 |
|