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UL 8750 故障测试中的8.7.2 中Exception No1对于不超过50W的电路可以豁免故障测试。三个问题' i2 R0 H! D; C( h9 w4 _
1.是不是说只要经过8.8 Circuit power limit measurement test的评估确定这个电路是小于50W的就可以豁免故障测试! _' j& J4 [; q/ L* C
2.这个50W的电路不论输出是高压还是低压都可以豁免吗?还是说低压输入的电路?5 z7 a' j& \6 ^1 j
3.目前有一个带电池的灯具,电池输出为12V,灯具只有10W,里面有电路,这个电路需要做故障测试吗?- P- f4 l( b: Z5 f* R: k
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. t+ Y# g+ b! M+ v3 k6 N6 y8.7.2 Component failure test
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0 X1 y% K! O3 e! [. v% t- B; D8.7.2.1 A unit having components such as resistors, semiconductor devices, capacitors, and the like shall: o) J3 z6 `9 ~: \+ ]
not exhibit a risk of fire or electric shock when a simulated short circuit or open circuit is imposed. In) t/ ^; {: Y; {2 n( f
preparation for component failure tests, the equipment, circuit diagrams, and component specifications( a/ b; v5 l2 {5 f% N+ V0 n
are examined to determine those fault conditions that might reasonably be expected to occur. Examples |' W v3 l6 @- K7 N: j; B" }4 F, I
include: short-circuits and open circuits of semiconductor devices and capacitors, faults causing open2 s: E1 G$ |+ A* D( \$ l* {9 b
circuits of resistors and internal faults in integrated circuits.
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Exception No. 1: Circuits in which maximum power levels have been determined to not exceed 50 W need
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% w1 o: \( d/ m1 v) s0 m7 zException No. 2: Devices supplied by a source operating within the limits for risk of fire and electric shock" A$ W* j1 O% [* ^2 s
need not be subject to this test.
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( o3 _9 T& O+ j2 n" s4 k8.8 Circuit power limit measurement test
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+ ^% [ \& W+ z/ p' i0 S8.8.1 This test shall be used to determine if the power available to a circuit under any loading condition,8 R) V4 H! d2 |' C u5 n3 f( @
including short circuit, measured after one minute of operation exceeds a defined limit. For the purposes
# u' n/ ]( m0 i+ H Gof this test, the limit (for example, 15W or 50W) is referred to as PLIMIT. This test is applied to a circuit
! w) i; t7 Q8 D) S# e" ?/ Q(under evaluation) to determine if it has a power draw of PLIMIT or less.
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