Experience of domestic electronic ballast of digital road is by the market and objective decision, it will not be because we simply agree to come round, also won’t because we simply refused to leave, but Europe and the United States, Japan and other advanced countries in energy conservation and environmental protection and lighting industry, digital electronic ballast is already in full swing in the world as a whole, green products hold sway today, believe that the domestic electronic ballast of digital road is soon coming HID lamp is a kind of high pressure gas discharge lamp, the discharge of the “V” performance showed a negative resistance characteristic, so the lamp circuit to be connected to the current limiting device, which is commonly referred to as ballast. HID lamp most work in AC state, the use of reactive devices as ballast. HID lamps have different types, according to the type of lamp and its application needs, can be configured in different forms of ballast circuit, in order to obtain the best matching ballast and lamp. The commonly used HID lamps for general lighting as a high-pressure mercury lamp, high-pressure sodium lamp and metal halide lamp. High pressure mercury lamp is in the earliest development, stable product performance, supporting mature ballast circuit. High pressure sodium lamp and metal halide lamp is modern development of new high efficiency energy-saving light source, the requirements for ballast and lamp has good matching, to achieve better comprehensive effect of high pressure sodium lamp and high pressure mercury lamp in the performance of different, high pressure sodium lamp not only mercury, but also filled with sodium, working in the light, sodium and mercury to form storage of liquid sodium and mercury gas in the discharge tube cold end part.
High pressure sodium lamp power during its lifetime, with the change of the lamp voltage change. The high-pressure mercury lamp (HPML) and different high pressure mercury lamp power changes in the lamp voltage relatively remained stable, because under the high pressure mercury lamp mercury vapor pressure in saturated condition. The relationship between high pressure sodium lamp voltage and lamp power is in the discharge tube contains excessive sodium caused by mercury gas based on. During operation of the lamp, only a portion of the mercury and sodium form vapor pressure, vapor pressure level can reflect on the lamp voltage, it depends on the discharge tube cold end of the temperature. The change of the cold end temperature causes the change of the vapor pressure, resulting in the change of the lamp voltage, and the change of the lamp power. In the relationship between certain power within the scope of the lamp voltage and lamp power approximate to linear relationship between C) best ballast characteristics curve to can make the lamp before the maximum voltage line to achieve the maximum power and the light power with the increase of the lamp voltage decreases. For a near the lamp design power line of relatively flat ballast characteristic curve than the relatively steep rise and fall of the characteristic curve more desirable d) to avoid shorten the lamp life, work or instability, ballast should can make the lamp from quadrilateral right maximum lamp electric pressure characteristics in high pressure sodium (HPS), international standards, lamps with different specifications to the ballast provides different quadrangle maps.The poor quality of the ballast will cause the lighting used during the super load operation, work or not stability Na-T1-In metal halide lamp from European manufacturing technology, the excellent performance of the lamp start, equipped with general inductance type ballast circuit, only need to trigger in the power supply voltage (220V), with lower peak voltage (less than or equal to 750V) can start the work lamp. The photoelectric performance parameters of a stable light, with a long life (average life 20000h), the characteristics of high luminous maintenance rate. After the performance improvement of Na-Tl-In type metal halide lamp, can be equipped with the same power type ballast for high pressure mercury lamp and high pressure sodium lamp ballast, and the average life of the metal halide lamp can still reach the required 20000h. So the metal halide lamp without changing the electrical appliances in the original lighting device can be conveniently replaced the original high pressure mercury lamp or high pressure sodium lamp, it is better than the former improves the light efficiency and improve the light color, also than the latter greatly improved chromogenic properties. Main parameters of the changes see table 2Sc-Na metal halide lamp from the manufacturing technique of the United States, the discharge tube structure similar to high pressure mercury lamp, working lamp the trigger and by means of the ballast for high open circuit voltage and lamp starting electrode effect, the lamp start working. If the Sc-Na type metal halide lamp using the Na-T1-h metal halide lamp circuit, not only will enable early lamps increase failure (initiation trigger fragile lamp electrode), shorten the lamp life expectancy, and increase the lamp light attenuation. As shown in Figure 9 for using different metal halide lamp “inductance ballast and trigger circuit of the decay curves on the one hand improve discharge tube structure, the abolition of the starting electrode, as shown in Figure 10B and improved chemical formula and manufacturing process, to improve the starting performance of the lamp, thus comprehensively improved the performance of the lamp. On the other hand, to improve the working circuit of the ballast, trigger to start the lamp work, so as to reduce the open circuit voltage of the ballast, which reduces the peak voltage and peak current. The working temperature of the ballast is correspondingly reduced, and increases the life span of the ballast, reduce maintenance costs in Table 4 for two types of Sc-Na metal halide lamp and ballast main performance parameters of the comparison of pulsed metal halide lamp starting Sc-Na can the better performance of the CWI and regulated.