Of the 70 luminaire products that were sampled in Guangzhou, 29 had unsatisfactory power supply terminal disturbance voltages. In the spot check results issued by the Beijing Municipal Administration of Industry and Commerce, all the 7 batches of products sampled were found to have unqualified disturbance voltage, and the failure rate was 100%. 
So, what is the power terminal disturbance voltage? How can lighting manufacturers avoid their products being unqualified?
What is the power supply terminal disturbance voltage?
From the perspective of standard testing, “power terminal disturbance voltage†is only one of many EMC test items. In addition, other EMC test items may be required, as shown in the following figure:
From a practical point of view, the power terminal disturbance voltage refers to the high-frequency interference generated by the luminaire and transmitted from the power terminal to the power grid through the wire, which may cause the adjacent electronic products to fail to work normally. The current national standard GB 17743-2007 "Limitations and Measurement Methods for Radio Disturbance Characteristics of Electrical Lighting and Similar Equipment" provides specific provisions for this. The limits of the power terminal disturbance voltage are shown in the following table:
In the actual test, the test equipment will generate a test curve corresponding to the above standard limits, as shown in the following figure.
Figure: Power terminal disturbance voltage test curve corresponding to the standard value
Here's how to read this test result graph.
In the figure, the abscissa is the test frequency and is displayed in logarithmic coordinates. The ordinate is the signal strength, the uppermost line represents the quasi-peak limit, and the lower line below it represents the average limit.
The two curves in the lower part of the picture are the preliminary test results of quasi-peak and average, respectively, and the points on the curve are the results of the fixed-point test at the frequency of maximum disturbance. As long as these points are below the corresponding limit line, it means that the power supply terminal disturbance voltage of the luminaire meets the standard requirements. Therefore, the test results in the figure are clearly qualified.
How can the luminaire harass voltage test through the power terminal?
After introducing the basic situation of the power terminal disturbance voltage, let's talk about how to make the lamp pass the test smoothly. I am afraid that everyone is most concerned about it.
However, since different luminaire structures, wiring, and electronic components may have different effects on the disturbance voltage test results, it is very difficult to find an ultimate and universal solution. Manufacturers and testing organizations often find out some empirical rules through continuous practice.
The following table is some of the coping strategies summarized by the technicians of the National Semiconductor Light-Emitting Device Application Product Quality Supervision and Inspection Center. For your reference, please don't hesitate!
Figure: Lighting improvement strategy for power terminal disturbance voltage test summarized by technicians of National Semiconductor Light-emitting Device Application Product Quality Supervision and Inspection Center
Anti-shock level classification
According to the form of electric shock, the lamps are classified into Class 0, Class I, Class II and Class III.
Class 0: Luminaires that rely on basic insulation as protection against electric shock.
Insulate only by the pvc of the wire. In case of basic insulation failure (wire breakage: broken skin when passing the line), resulting in electric shock and fire hazard. Protection against electric shock has to rely on the environment.
In 2007, the luminaire standard has banned the use of Class 0 luminaires. In the unqualified products of this sampling, there are still 0 types of luminaires. If it is, it can be divided into environments, such as air drying, less dust, wooden floors, etc. Under the conditions, you can use chandeliers and ceiling lamps. This is not a joke. The danger of electric shock of such lamps can be imagined. If you are not careful, it will be cool.
Class I: (Class 0 luminaire + ground) The protection against electric shock of the luminaire not only relies on basic insulation, but also includes additional safety measures.
Connect the accessible conductive parts to the protective earth conductors in the fixed line of the facility so that the accessible conductive parts do not become charged in the event of a failure of the basic insulation. Used for metal casing lamps, such as floodlights , street lamps, garden lights, etc., to improve safety.
Class II: Protection against electric shock not only relies on basic insulation, but also has additional safety measures.
For example, double or reinforced insulation, but without protective grounding or depending on safety conditions. It has a high degree of safety and is suitable for lamps that are inferior to the environment and often touched by people, such as table lamps and hand lamps.
Class III: Anti-shock protection relies on the power supply voltage as a safety extra low voltage, and the lamp does not generate a low voltage higher than SELV (36v).
Converting utility power to a low voltage of 36v (plus transformer), Class III lamps are the safest for harsh environments, such as machine work lights, children's lights, etc.
Anti-shock level symbol description
Figure: Anti-shock level symbol description, when buying a lamp, be sure to see the symbol description of this anti-electricity level, this is not a joke, don't be greedy, the picture is happy at the time, regret later.
From the perspective of electrical safety, Class 0 luminaires have the lowest safety, Ι and II are higher, and Class III is the highest. In the lighting design, the appropriate types of lamps should be selected according to factors such as the environmental operation object, installation and use position of the place of use. Class III lamps shall be used in harsh places where the conditions of use or methods of use are used. In general, sputum or class II lamps may be used.
When purchasing a luminaire, how do you tell if it is a Class 0 luminaire?
1. Simply put, it is generally a double-headed plug with no grounding protection. The wire has only a simple insulating layer, that is to say, there is only one layer of rubber, no sheath, and the copper wire can be seen by peeling off the rubber. Once the insulator is aged or the quality is not good, it is easy to cause an electric shock or fire.
But not absolutely!
Some lamps, although the plug is two-wire, but has a "back" character number, which means that it has a double protection measure. Therefore, in addition to looking at the plug, a more reliable method is to see if there is a type II symbol ("back") on the product identifier, so as not to accidentally kill the class II.
Seeing this, it is estimated that you will go to your own home to see if it is a class 0.
What kind of lamps did you buy at home before? (Buy now is the 0 class and hurry back!) If you can't bear to throw it, you can also improve the safety factor through transformation.
Wall lamps, ceiling lamps, etc. can be connected to the grounding wire, and the wires are replaced with sheathed wires. A luminaire with a metal casing can also be connected to a grounding wire in a metal casing. The wire can be converted into a Class I luminaire by changing it to a sheathed wire to reduce the risk of electric shock and short circuit.
Spinning is to fix the flat or hollow billet to the die of the spinning machine. While the billet rotates with the spindle of the machine tool, the billet is pressed with a rotating wheel or a driving rod to make it produce local plastic deformation. Spinning is a special forming method. The drawing, flanging, shrinkage, bulging and flanging of rotating bodies of various shapes can be completed by spinning method.
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