LED灯管的电源UL要做overload吗？

jsspace

跟产品一起做这个测试，很容易通过。

xiaodeng

保险电阻是需要做的。 是放到产品上做，先算出保险电阻的电压，然后再给两端施加电压，先从1U开始，一直到5U，中间但是每次都需要等一分钟，如果保险电阻的熔断时间慢的话产品会烧坏或者会起火，如果熔断时间快，基本上到4U或者3U就熔断了。 此测试是14年才需要去做的！

songbolove

UL 1412
3 F0 t6 b: c  M+ X4 |15 Overload Test
! U/ _" U- w  I" j15.1 A resistor shall withstand the overload test described in this section without resulting in a fire.
2 @8 m* m: ^3 l4 R15.2 A single layer of cheesecloth is to be wrapped around, and be in contact with, the resistor under test.
Exception: At the manufacturer’s option, the cheesecloth may be spaced 1/2 inch (127 mm) – or 1 inch
2 q( o5 ?$ k. I4 A' g! n(25.4 mm) for a resistor rated greater than 10 W – from the resistor body as described herein. In this case,
* ~& [% ]$ E/ ^* p* S( T: B9 n, fa positive spacing of 1/2 inch (or 1 inch, as appropriate) between the resistor body and combustible
materials is to be provided in the complete appliance. A single layer of cheesecloth is to be placed around
the resistor under test to form a cylinder with open ends. The length of the cylinder is not to be less than
: s  _# V" Y5 u1 O9 o& bthree times the length of the resistor body and the diameter of the cylinder is to be such that the
$ Q9 h. J& i; M9 o4 Q6 Echeesecloth is spaced 1/2 inch (or 1 inch, as appropriate) from the outermost part of the resistor body.
The resistor body is to be centered end-to-end within the cylinder and the longitudinal axis of the resistor
body is to be coincident with the longitudinal axis of the cylinder.
15.3 The resistor is to be connected to a 60-Hz variable voltage source of supply fused at 30 A. Prior to
energizing, the supply voltage is to be adjusted to produce rated current (or rated power dissipation) in
the resistor. At 1-minute intervals after energizing, the supply voltage is to be raised in steps of 2, 3, 4, 5,
and so forth, times that initial voltage until the resistor opens. In no case is the voltage rating of the resistor
% R; b: [& l9 Vto be exceeded.
0 u: G: P0 A& d. B1 m4 Z8 ?* @5 T15.4 Five complete separate tests are to be made using new samples for each test.
, P! `' c( a9 o15.5 The results are not acceptable if the cheesecloth flames.
15.6 The cheesecloth used for the overload test shall be untreated cotton cloth 36 inches (0.9 m) wide,
# a- L: h. g# v  Urunning 14 – 15 yd2 /lb and having what is known to the trade as a count of 32 by 28.

jsspace

xiaodeng 发表于 2014-12-1 08:42
保险电阻是需要做的。 是放到产品上做，先算出保险电阻的电压，然后再给两端施加电压，先从1U开始，一直到5 ...

3 S1 y' _# [. x" ^哥，我2012年就做了这个测试，怎么说2014年才有这个要求呢。
这是UL1412上的要求，应该很早就有了

xiaodeng

jsspace 发表于 2014-12-1 10:29
& |- ]. Q3 \6 s- c哥，我2012年就做了这个测试，怎么说2014年才有这个要求呢。
这是UL1412上的要求，应该很早就有了

但是13年的时候做带电阻保险的这种项目只做了大电流冲击测试。只是今年才开始要求这样做的。

addwin

jsspace 发表于 2014-12-1 08:25
/ u1 G4 Z5 _' O( ^: \6 b" T( \9 k. A跟产品一起做这个测试，很容易通过。

; a- K8 c( C& ^6 `# y$ N+ u- D你说的是大电流测试吧。over load这个测试是2014新增加的。需要做over load 慢慢提升电压来令保险丝发热，最终保险丝会通红，如果产品塑料贴近保险丝基本就起燃碳化，主要看保险丝和产品结构并不容易通过的。

jsspace

addwin 发表于 2014-12-1 16:14
' ]" _. M0 W4 V2 I  Q你说的是大电流测试吧。over load这个测试是2014新增加的。需要做over load 慢慢提升电压来令保险丝发热， ...

恩，是的，我说的是大电流测试