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5.1 Spark test after insulating & j9 b$ }. a3 p, r. a9 [
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5 m; e7 L! Q0 T( H: a3 bThe 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; # @" a- M- ~: W4 Z1 b- `( Z; _
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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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5 mA. Any ripple shall not exceed 1 per cent. After a fault, the dc test voltage shall recover to the full
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4 Q. t; g0 X/ J5 L. J% Ztest voltage in 5 ms or less, unless 610 mm (2 ft) or less of the product travels through the electrode8 T+ m6 v: b5 y4 d- ^' v" d" j: J
e in the time that it takes for the full voltage recovery; : B- N) Q. l& Y) j7 T$ Z; J6 G4 _1 ?
3 @- `$ [& f6 r2 F8 ^2 T4 E' s2 ~c) For conductor gauge sizes 22 – 30 AWG which are to be used in cables without coaxial membe3 N" o) Q% @! Q4 J7 [; N! P
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rs but with foam or foam skin insulation and protected by bonded metal shields, the following spar
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k test voltage may be used:
$ H* B( S: J8 L! M# ` Conductor size Test Voltage
3 I( h: y( q! P( r7 x X5 } 22, 23 AWG 1500 V dc or 1050 V ac
/ g, K5 k! k; z2 f- i 24, 25 AWG 1200 V dc or 850 V ac ! j6 E# i1 s) E& i
26–30AWG 1000Vdcor750Vac # v& F2 E. H1 v/ n. W. `
8 \2 r3 n& x+ F- e( m9 ]+ g8 rd) For cables without bonded metal shields, and with foam insulation that is not more than 0.20 m
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- q) \* K5 c% R. j1 Z7 Bm (0.008 in) in average thickness and does not have a skin, the spark test voltage may be reduced
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8 f) u3 ^: g. b, l) M/ d to 1250 V ac or 1750 V dc, provided that the dielectric strength test voltage required by Clause / Q8 I6 ^: ^3 u" o3 h
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5.3.5 is met. ) ]: S6 e, D( g8 x3 l2 X
1 W$ F- r. ]( f4 x5 L& o5 G! T% P# e这段内容看得有点糊涂,前辈们可否指导一下?
: d1 h. N, R- M7 A" B* n% r问题1. 首先我不理解d)中所涉及的skin在实物中是什么?
+ X$ a, Q0 i _2 R) Y问题2. c)中foam 和foam skin 有何区别?
3 m L7 x) j5 p a我想先把这个问题搞清楚了 |
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