琥珀流云 发表于 2016-10-11 11:21

UL8750电容短路测试

有哪位高手懂UL8750 LED driver的

我们有一款LED driver,使用两个大电容串联,在短路其中一个电容的时候,另外一个电容喷液了,我们的电源内部全部灌胶,如果耐压测试通过是否可以?

jsspace 发表于 2016-10-11 11:34

漏液不可以接受,不管是否灌胶。

fasten 发表于 2016-10-11 12:39

jsspace 发表于 2016-10-11 11:34 static/image/common/back.gif
漏液不可以接受,不管是否灌胶。


8.7.1.2 After ultimate results have been obtained for each test, the sample shall be permitted to cool to
room temperature and the dielectric voltage withstand test of 8.6 shall be repeated.
8.7.1.3 A risk of fire or electric shock is considered to exist with any of the following results:
a) Opening of the ground fuse,
b) Charring of the cheesecloth or tissue paper,
c) Emission of flame or molten material from the unit,
d) Ignition or dripping of a compound from the unit,
e) Exposure of live parts that pose a risk of electric shock under the requirements for
accessibility of 7.2, or
f) Breakdown during the subsequent dielectric voltage withstand test.
Opening of the 20A time delay fuse is acceptable provided none of the other conditions noted in (a)
through (f) occurs.



8.7.2 Component failure test
8.7.2.1 A unit having components such as resistors, semiconductor devices, capacitors, and the like shall
not exhibit a risk of fire or electric shock when a simulated short circuit or open circuit is imposed. In
preparation for component failure tests, the equipment, circuit diagrams, and component specifications
are examined to determine those fault conditions that might reasonably be expected to occur. Examples
include: short-circuits and open circuits of semiconductor devices and capacitors, faults causing open
circuits of resistors and internal faults in integrated circuits.
Exception No. 1: Circuits in which maximum power levels have been determined to not exceed 50 W need
not be evaluated for component failure.
Exception No. 2: Devices supplied by a source operating within the limits for risk of fire and electric shock
need not be subject to this test.
8.7.2.2 Each component is to be short circuited or open circuited, one at a time (one fault per test). Each
test shall continue until either the unit is no longer operable, or until conditions are obviously stable (as
determined by no visual.


再核对一下标准看有没有答案?

jsspace 发表于 2016-10-11 14:16

本帖最后由 jsspace 于 2016-10-11 14:30 编辑

fasten 发表于 2016-10-11 12:39 http://bbs.angui.org/static/image/common/back.gif
8.7.1.2 After ultimate results have been obtained for each test, the sample shall be permitted t ...

但奇葩的是UL内部有很多工程判断
这个问题,我刚刚发邮件跟UL重新确认了一下,现在的做法是如果漏液没有益处到外壳外面,且耐压测试通过,可以接受。

琥珀流云 发表于 2016-10-11 16:12

非常感谢,我问的UL 工程师是说不行~~,这个标准也很烂,工程师判断也不一样~·~麻烦·~~

jsspace 发表于 2016-10-11 17:02

琥珀流云 发表于 2016-10-11 16:12 static/image/common/back.gif
非常感谢,我问的UL 工程师是说不行~~,这个标准也很烂,工程师判断也不一样~·~麻烦·~~

你在问问吧,我今天问的,他说可以
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