标题: 请教： UL444 火花测试 [打印本页] 作者: cathyma1986 时间: 2009-9-30 10:44 标题: 请教： UL444 火花测试 5.1 Spark test after insulating T9 d$ Q3 l1 Z6 d- g! {' z7 V / I3 m; c3 U) r* j* S/ M$ b/ r1 l; @! i& J6 i1 ]" i$ @$ H
The voltage source of a dc or ac spark tester shall maintain the following test voltage under all nor % @9 k5 z S- s* L! {, g) P& V0 s4 r- o
mal conditions of leakage current: 8 p1 A% |8 G! |8 M8 Z4 @4 r8 ]0 o+ E) {
a) An essentially sinusoidal rms potential of 1750 V for an ac test; ' ? q0 N3 d# q+ z/ @9 M
$ K8 R0 k* z. j! t7 e& k0 xb) 2500 V for a dc test. The current output of which the dc power supply is capable shall not exceed $ r/ J) t% c+ Y) s4 N+ e$ D6 s$ P2 t% [0 F
5 mA. Any ripple shall not exceed 1 per cent. After a fault, the dc test voltage shall recover to the full ! u! ~" E* L. v1 s: S& s- m/ o. G, u4 I/ a! D" o) t$ @5 ^
test voltage in 5 ms or less, unless 610 mm (2 ft) or less of the product travels through the electrode7 A: K9 E" w0 _3 I0 M
e in the time that it takes for the full voltage recovery; & ^4 N9 ~! z# a' T0 d1 i6 e ( G) A* C1 p. t' u9 I: Y/ Fc) For conductor gauge sizes 22 – 30 AWG which are to be used in cables without coaxial membe 3 s/ R. g) K8 `1 H9 o5 Z8 i 5 ^9 {; P. D6 j6 Z& t' krs but with foam or foam skin insulation and protected by bonded metal shields, the following spar % |3 A0 g( e' H; g2 W 6 X* U! g$ B f. o( nk test voltage may be used: 4 I0 p. u0 N+ K1 h4 j; ]$ c Conductor size Test Voltage 1 C; S1 L8 n4 c
22, 23 AWG 1500 V dc or 1050 V ac * ]) ^8 z J6 t+ J
24, 25 AWG 1200 V dc or 850 V ac 5 K- e) o8 v" _4 A2 r7 _
26–30AWG 1000Vdcor750Vac 6 D& n4 j. W6 |* T+ Z5 Y3 F0 z
& [+ _8 `) o. r. X& P7 |6 od) For cables without bonded metal shields, and with foam insulation that is not more than 0.20 m& x, v- f- @4 Z, g9 D
2 K. d) E# s7 t- T
m (0.008 in) in average thickness and does not have a skin, the spark test voltage may be reduced 6 y$ {6 [; ?% m; i5 Y & p) }+ v0 I( U5 v: B; I: g- A8 C to 1250 V ac or 1750 V dc, provided that the dielectric strength test voltage required by Clause % N. H. S/ ?9 F3 @$ J% ]8 Z
