What points should be paid attention to in the UL certification test of various lighting lamps?
As an international product safety testing and certification organization, UL is also the founder of American product safety standards. In the United States, UL certification has long been deeply rooted in the hearts of the people; in China, UL is mainly to help customers pass UL certification tests as soon as possible, and to gain more time and greater confidence for customers to win international orders.
So, these shortcomings should be taken seriously and resolved. Below I have summarized some of the details and precautions in the UL certification test of lamps and mainly related to the introduction of the test, etc., and show them for your reference. If there are deficiencies, please write to me for corrections.
Self-ballasted lamp (energy-saving lamp)
According to the self-ballasted lamp testing standard UL1993, the main test items are:
1. Input parameter measurement
In this test, the working position of the energy-saving lamp is placed with the lamp cap facing up. The tested energy-saving lamp sample must be ignited for 100 hours at a rated voltage of 120V in advance, and then check whether it can be activated and lighted normally. Then test input parameters on these samples, including current, power, and power factor. The judgment result is that the current cannot exceed 110% of the rated current, and the power cannot exceed 110% of the rated power. Based on these, the manufacturer can pre-test by itself.
2. Weight limit test
The design of energy-saving lamps must meet the parameter requirements of the following table
Note: The maximum torque refers to the maximum torque that the energy-saving lamp can bear after the lamp is installed. Generally, when the energy-saving lamp is installed horizontally, the distance from the center of the lamp to the center of gravity of the energy-saving lamp multiplies the weight of the lamp itself.
3. Safety test of threaded lamp cap
According to the provisions of the UL496/CSA C22.2 No.84-95 standard, the threaded lamp cap of the energy-saving lamp must be able to withstand 20lbs (89N) axial tension for 1 minute and withstand 20lbs-in (2.26Nm) of the lamp cap rotating torque test , The lamp cap cannot be rotated, shifted, pulled off, broken, etc. Nail holes on the lamp holder can realize the close positioning and assembly between the metal lamp holder and the plastic lamp body. Of course, there are other methods, such as gluing. However, thermal expansion and contraction may affect the adhesive properties of the adhesive.
4. Leakage current test
Generally, the leakage current of lamps using fluorescent tubes is greater than that of lamps using incandescent lamps. The leakage current limit of the self-ballasted lamp shell is 0.5mA. This is a comprehensive index, which may be related to the spatial distribution of the current-carrying parts of the product itself, the size of the shell gap, etc. Although 0.5mA is not a very demanding index, if the manufacturer is not sure, it is recommended to send samples first. Go to our company's laboratory to do a thorough test on this indicator.
5. Normal/abnormal working temperature test
There are two tests included here: normal operation and abnormal operation (deactivation of lamp components).
The energy-saving lamp is installed in a cylindrical installation box with a diameter of 152mm and a depth of 216mm with the lamp head facing upwards, with the opening of the tube facing downwards. The sample is first measured for normal working temperature, after recording the stable (generally at least 3 hours) temperature value of each measured point, then it turns to abnormal working state until the end.
Abnormal working state refers to the deactivated working state of the fluorescent tube part, specifically refers to cutting off one end of the fluorescent tube (a pair of wires) on the original energy-saving lamp and connecting it to one end of the other lamp tube (a pair of input wires) Above, only one end of the two lamps is connected to the circuit of the energy-saving lamp. Energy-saving lamps are best designed to contain fuses to prevent this abnormal working state from continuing for a long time, causing the temperature of each temperature measured point to exceed the limit.
For the UL certification test of lamps and lanterns, the temperature test is a very important link. All electronic components, circuit boards, shell plastic materials, internal wires, etc. in energy-saving lamps have certain temperature limits. Manufacturers should select various components and plastic materials that have passed UL certification and ensure that they are at a certain heat-resistant temperature level. To ensure that the temperature test can pass smoothly.
6. Insulation withstand voltage test
The key is that if the housing assembly gap of the lamp itself is small and the assembly mating surfaces have a certain misalignment, it can roughly withstand the high voltage of 2500V applied to the live parts and the housing plastic. In addition, these mating surfaces and plastic materials should be ensured to work normally. It will not melt and deform so as to meet the insulation performance of the lamp itself.
7. Failure state test of components
The test mainly examines whether the components in the lamp are under the fault condition of simulating a short open circuit, and whether the lamp has the dangers and tendency of melting of materials, exposure of charged body, and flame. In addition, check whether the fuse in the circuit (it is recommended that the manufacturer must include the fuse in the circuit design) can operate normally and promptly for protection. The components to be tested include capacitors, diodes, coils, etc.
8. Drop test
The sample falls freely onto a wooden board from a height of 0.91m. After the test, the shell can not show cracks, etc. and can still withstand the high voltage insulation test of 2500V.
9. Molding stress test
Put the lamp sample in an oven for 7 hours to heat up. The oven temperature is set to 70°C or the highest temperature value of the shell plastic measured in the temperature test plus 10°C. For energy-saving lamps, according to the measured value of the shell temperature obtained in the normal temperature test, the general oven needs to set the temperature Both will exceed 70°C, and according to our laboratory's summary, it should be around 140°C. After the test, the sample should not be melted or cracked.
10. Mechanical strength of housing
The shell impact test is required, that is, an impact ball weighing 0.5kg is used to freely drop the shell of the impact appliance from the air. The impact energy can correspond to the following table, and the shell should not be broken after the test.
11. Withstand voltage test of circuit board
The energy-saving lamp contains a ballast circuit. The working voltage of each point in the circuit is not consistent. There may be a large voltage difference at some points. Because the distance between the points on the circuit board is very small, except for component failure tests In addition, considering the insulation safety between points on the circuit board, this test is required. Manufacturers are mainly required to pay attention to the wiring design, spacing, and soldering technology of the circuit board. Too long component pins should be fastened with suitable size sleeves, and the tin point should not be too large, but generally this The test is not very harsh.
Most of the tests involved in energy-saving lamps are introduced here. A small amount of supplementary tests may need to be added depending on the structure of the specific product, but as long as the above tests can be passed smoothly, the additional tests will not be too difficult.
In addition, you need to pay attention to:
1. The energy-saving lamp housing mentioned above does not include the glass tube part;
2. The components involved in the luminaire should use UL certified components as much as possible, and even circuit boards, pin bushings, etc. should use UL certified components.
3. The shell plastic must be a UL-certified plastic material. The manufacturer can choose the appropriate grade of plastic material according to the highest shell temperature of the product itself. It is not necessary to be too high, but because the shell plastic is directly connected to the current-carrying metal parts of the lamp holder Contact, so the flame resistance rating should reach V level.
China is a major producer and marketer of lighting electrical products. The exported lighting products mainly include all kinds of table lamps, wall lamps (fluorescent lamps), chandeliers, various craft lamps, night lamps, work lamps, portable lamps, festive lighting and so on. However, as far as the UL certification test is concerned, many of the details of the materials, structures, etc. of these products are often ignored by the manufacturers, and many manufacturers are in a hurry when applying for the UL certification of their products because of insufficient understanding of the requirements of the UL certification test. At the experimental stage, there is still a fluke mentality. When the problem is exposed, it often takes a lot of time and even leaves a lot of bad impressions on his international order customers.
