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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$ k* J& H1 V4 `: C/ w7 \( Q6 ~
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; Q/ T8 o1 i7 Y) R4 D
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?
Y& x2 c5 X5 c/ a3.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?
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8.7.2 Component failure test
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8.7.2.1 A unit having components such as resistors, semiconductor devices, capacitors, and the like shall
3 i# ~; [, g/ D% J! _7 D t( Cnot exhibit a risk of fire or electric shock when a simulated short circuit or open circuit is imposed. In
. m8 Z `, P4 l Tpreparation for component failure tests, the equipment, circuit diagrams, and component specifications; Y/ ^4 G( p* A/ L$ w$ f& }
are examined to determine those fault conditions that might reasonably be expected to occur. Examples
3 C9 d. r: A R# r4 l/ ^5 tinclude: short-circuits and open circuits of semiconductor devices and capacitors, faults causing open
1 i$ V* L6 A5 L! r0 P3 h! tcircuits of resistors and internal faults in integrated circuits.
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+ C' r( E& e( g( ZException No. 1: Circuits in which maximum power levels have been determined to not exceed 50 W need0 t9 ?1 L* Y" w
not be evaluated for component failure.
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" A# u: d" @ S# |6 V6 N: CException No. 2: Devices supplied by a source operating within the limits for risk of fire and electric shock' ]* R$ s% e& L" o0 e
need not be subject to this test.
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8.8 Circuit power limit measurement test! d; _' x2 k( F+ i
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8.8.1 This test shall be used to determine if the power available to a circuit under any loading condition,6 S! ?; z% X0 c
including short circuit, measured after one minute of operation exceeds a defined limit. For the purposes
- J" _# d5 w [6 [$ ?8 C# |of this test, the limit (for example, 15W or 50W) is referred to as PLIMIT. This test is applied to a circuit4 Q% c2 E/ k( q# I/ z/ K n) |
(under evaluation) to determine if it has a power draw of PLIMIT or less.
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