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5.1 Spark test after insulating
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The voltage source of a dc or ac spark tester shall maintain the following test voltage under all nor
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mal conditions of leakage current:
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a) An essentially sinusoidal rms potential of 1750 V for an ac test;
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b) 2500 V for a dc test. The current output of which the dc power supply is capable shall not exceed
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) L$ a0 \- I0 x" ~2 z 5 mA. Any ripple shall not exceed 1 per cent. After a fault, the dc test voltage shall recover to the full 2 K3 ?8 |# f& B, x! D! A5 V
) @! p" d' ^ utest voltage in 5 ms or less, unless 610 mm (2 ft) or less of the product travels through the electrode; b: ~0 ~0 ^; D9 O3 k7 ?; X: t
e in the time that it takes for the full voltage recovery; 9 s2 i ^2 ^2 e8 `
2 T* U9 i( c* m# \. `c) For conductor gauge sizes 22 – 30 AWG which are to be used in cables without coaxial membe
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rs but with foam or foam skin insulation and protected by bonded metal shields, the following spar: H! d& U! i( k5 A# k; w X
, a; Q3 A: o u0 C; N" Z4 sk test voltage may be used:
/ C0 ], ?! [& w% f Conductor size Test Voltage
$ y/ f! Z9 m* X0 ]' F( a 22, 23 AWG 1500 V dc or 1050 V ac $ a0 P# H2 Q" N5 R; q, {
24, 25 AWG 1200 V dc or 850 V ac 5 Z1 Y6 i/ q2 u Z! o" Y* S% _% {
26–30AWG 1000Vdcor750Vac
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d) For cables without bonded metal shields, and with foam insulation that is not more than 0.20 m5 _* v9 [$ T/ E+ ?- K9 z
5 ?9 G7 ?( a' o3 hm (0.008 in) in average thickness and does not have a skin, the spark test voltage may be reduced
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- j n+ a/ i" |( a4 y" X* M to 1250 V ac or 1750 V dc, provided that the dielectric strength test voltage required by Clause
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5.3.5 is met.
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+ e$ I; c0 g ~# `4 }这段内容看得有点糊涂,前辈们可否指导一下?
' i6 E' ^+ L7 a8 p问题1. 首先我不理解d)中所涉及的skin在实物中是什么?9 x7 p/ }5 T' D3 ^
问题2. c)中foam 和foam skin 有何区别?& c6 n! r# H4 K/ c& w7 Y) U
我想先把这个问题搞清楚了 |
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