The life of fluorescent lamp electrodes is a key indicator of the quality of fluorescent lamps. Therefore, in the standards of various national and international starters, fluorescent lamps and ballasts that have been developed, there are strict regulations in the relevant provisions to prevent premature fluorescent lamp electrodes. loss. In general, the relevant standards generally have the following principles in terms of ensuring the life of the preheated fluorescent lamp electrode:
1. Cold state does not allow high open circuit voltage to cause cold start.
Before the cathode reaches the emission state, the open circuit voltage across the lamp and the open circuit voltage of the auxiliary actuator (if there is an auxiliary actuator) should be lower than the level at which the gas can be blown down in the cold state, causing a glow current. During this time, even if it is narrow, the pulse of the rms value is hardly affected, but the peak value of the pulse is higher than the cold open circuit voltage allowed by the lamp. (The glow starter can be appropriately reduced. ).
2, to have a suitable preheating current and action time
The temperature of the lamp cathode is determined by the preheating current flowing through the filament and the time during which the current is applied (i.e., the thermal work done by the current). This preheating current is too small and too large to impair the life of the lamp. Practice has proved that due to the thermal inertia of the lamp cathode, it is impossible to reach the cathode which does not significantly damage the lamp and the emitter of the lamp reaches the emission temperature within 0..4s.
3. Breakdown after completion of preheating - glow-arc conversion process is fast, and the cathode should still be at the emission temperature
When the cathode of the lamp is heated to the emission temperature, the open circuit voltage of the lamp should be rapidly increased above the thermal start open circuit voltage level required for the lamp to ensure the glow discharge of the gas discharge after the gas breakdown (trigger) of the lamp The process of converting into an arc discharge can be completed quickly, and it is not allowed to generate a flash after multiple flashes.
The specific performance in GB/T10682-2002 (neqIEC60081:1997) "Double-end fluorescent lamp performance requirements" and GB/T17262-2002 (neqIEC60901: 2000) "single-ended fluorescent lamp performance requirements" standard, are different for different frequencies, different power, different Various types of parameters for the type of cathode and different types of fluorescent lamps are strictly regulated, such as voltage at the rated voltage, cathode preheating voltage, open circuit voltage, preheating current and warm-up time, start-up time, and lamp voltage during stable operation. Various indicators such as lamp current have specific regulations to ensure the life of fluorescent lamps.
In QB2276-96 (idtIEC60155:1995) "Fluorescent Starter" and GB/T19655-2005 (idtIEC60927:1996) "Light Accessories Starter (Except Glow Starter) Performance Requirements" standard, for fluorescent lamp starters and Several indicators affecting the cathode of the fluorescent lamp, such as the starting speed of the starting device, the cathode preheating, the pulse voltage and the non-repetitive starting voltage, are also strictly regulated. In GB/T14044 (modIEC60921:1994) "performance requirements for ballasts for tubular fluorescent lamps" and GB/T14044-2005 (idtIEC60929:2002) "performance requirements for AC electronic ballasts for tubular fluorescent lamps", both are There are two provisions on the voltage and preheating conditions at both ends of the lamp. In particular, preheated electronic ballasts have stricter preheating energy and open circuit voltage parameters and detection methods, which require special attention and understanding in the inspection. At present, the world's latest high-frequency lamp T5, including general power density and high power density (HO), has adopted this preheating evaluation method, and this method will also be adopted for the standardized T4 lamp. Preheating fluorescent electronic ballasts can be divided into control cathode heating energy type and control cathode heating current type according to different preheating control parameters, which have maximum and minimum cathode preheating energy and maximum and minimum preheating current, respectively. Open circuit voltage limit.
The development, implementation and implementation of this series of standards have played a very positive role in improving the quality and longevity of fluorescent lamps.
4. Problems that users should pay attention to when using fluorescent lamps
The quality of fluorescent lamp life quality should first be solved by researchers, standard setters, producers and detectors, but each user should pay attention to the following problems during the process of purchasing and using, in order to ensure the long-term safety of fluorescent lamps. Use to save on the trouble and cost of replacement.
1) When purchasing, try to buy a preheated high-frequency electronic ballast and a fluorescent tube that matches it, and then consider the magnetic ballast and the fluorescent tube that matches it. If an inductive ballast fluorescent lamp is purchased, it is best to use an electronic starter instead of a glow starter (but the electronic ballast and electronic starter are relatively expensive).
2) Try to ensure that the lamp is supplied with the rated voltage. Because the change of the power supply voltage has an effect on the life of the fluorescent lamp, the current of the lamp becomes larger when the supply voltage is increased, and the overheating of the electrode causes the two ends of the lamp to be blackened early and the life is shortened. When the power supply voltage is low, the operating current is low due to the low voltage after startup, which is insufficient to maintain the normal operating temperature of the electrode, thereby aggravating the sputtering of the cathode emitting material and shortening the life of the lamp. Therefore, the supply voltage offset range is required to be ±10%%.
3) Try to reduce the number of fluorescent light switches when possible, because fluorescent lamps are the most harmful to the electrodes during the start-up phase, and the general tungsten lamps do not have this disadvantage. In particular, a fluorescent lamp using an inductive ballast is equivalent to a continuous illumination of the lamp for two hours each time the lamp is activated. Users should avoid switching fluorescent lamps frequently if it is not necessary.
4) Ambient temperature also has an effect on the use of fluorescent lamps. Generally, the ambient temperature below 10 °C makes the lamp start difficult, and the optimum environment for the lamp to work is (20-35) °C.
5) Excessive ambient humidity (75%% to 80%%) is also detrimental to the start-up and normal operation of fluorescent lamps. When the humidity is high, the moisture in the air forms a moist film on the surface of the lamp tube, which is equivalent to a resistor bridging between the two poles of the lamp tube, which improves the starting voltage of the fluorescent lamp and makes the lamp start difficult. As the starting voltage is increased, the filament preheating starting current is increased, and the cathode physical loss is increased, thereby shortening the life of the lamp. Generally, the relative humidity below 60%% is the most unfavorable for the fluorescent lamp to work at 75% to 80%.
1. Cold state does not allow high open circuit voltage to cause cold start.
Before the cathode reaches the emission state, the open circuit voltage across the lamp and the open circuit voltage of the auxiliary actuator (if there is an auxiliary actuator) should be lower than the level at which the gas can be blown down in the cold state, causing a glow current. During this time, even if it is narrow, the pulse of the rms value is hardly affected, but the peak value of the pulse is higher than the cold open circuit voltage allowed by the lamp. (The glow starter can be appropriately reduced. ).
2, to have a suitable preheating current and action time
The temperature of the lamp cathode is determined by the preheating current flowing through the filament and the time during which the current is applied (i.e., the thermal work done by the current). This preheating current is too small and too large to impair the life of the lamp. Practice has proved that due to the thermal inertia of the lamp cathode, it is impossible to reach the cathode which does not significantly damage the lamp and the emitter of the lamp reaches the emission temperature within 0..4s.
3. Breakdown after completion of preheating - glow-arc conversion process is fast, and the cathode should still be at the emission temperature
When the cathode of the lamp is heated to the emission temperature, the open circuit voltage of the lamp should be rapidly increased above the thermal start open circuit voltage level required for the lamp to ensure the glow discharge of the gas discharge after the gas breakdown (trigger) of the lamp The process of converting into an arc discharge can be completed quickly, and it is not allowed to generate a flash after multiple flashes.
The specific performance in GB/T10682-2002 (neqIEC60081:1997) "Double-end fluorescent lamp performance requirements" and GB/T17262-2002 (neqIEC60901: 2000) "single-ended fluorescent lamp performance requirements" standard, are different for different frequencies, different power, different Various types of parameters for the type of cathode and different types of fluorescent lamps are strictly regulated, such as voltage at the rated voltage, cathode preheating voltage, open circuit voltage, preheating current and warm-up time, start-up time, and lamp voltage during stable operation. Various indicators such as lamp current have specific regulations to ensure the life of fluorescent lamps.
In QB2276-96 (idtIEC60155:1995) "Fluorescent Starter" and GB/T19655-2005 (idtIEC60927:1996) "Light Accessories Starter (Except Glow Starter) Performance Requirements" standard, for fluorescent lamp starters and Several indicators affecting the cathode of the fluorescent lamp, such as the starting speed of the starting device, the cathode preheating, the pulse voltage and the non-repetitive starting voltage, are also strictly regulated. In GB/T14044 (modIEC60921:1994) "performance requirements for ballasts for tubular fluorescent lamps" and GB/T14044-2005 (idtIEC60929:2002) "performance requirements for AC electronic ballasts for tubular fluorescent lamps", both are There are two provisions on the voltage and preheating conditions at both ends of the lamp. In particular, preheated electronic ballasts have stricter preheating energy and open circuit voltage parameters and detection methods, which require special attention and understanding in the inspection. At present, the world's latest high-frequency lamp T5, including general power density and high power density (HO), has adopted this preheating evaluation method, and this method will also be adopted for the standardized T4 lamp. Preheating fluorescent electronic ballasts can be divided into control cathode heating energy type and control cathode heating current type according to different preheating control parameters, which have maximum and minimum cathode preheating energy and maximum and minimum preheating current, respectively. Open circuit voltage limit.
The development, implementation and implementation of this series of standards have played a very positive role in improving the quality and longevity of fluorescent lamps.
4. Problems that users should pay attention to when using fluorescent lamps
The quality of fluorescent lamp life quality should first be solved by researchers, standard setters, producers and detectors, but each user should pay attention to the following problems during the process of purchasing and using, in order to ensure the long-term safety of fluorescent lamps. Use to save on the trouble and cost of replacement.
1) When purchasing, try to buy a preheated high-frequency electronic ballast and a fluorescent tube that matches it, and then consider the magnetic ballast and the fluorescent tube that matches it. If an inductive ballast fluorescent lamp is purchased, it is best to use an electronic starter instead of a glow starter (but the electronic ballast and electronic starter are relatively expensive).
2) Try to ensure that the lamp is supplied with the rated voltage. Because the change of the power supply voltage has an effect on the life of the fluorescent lamp, the current of the lamp becomes larger when the supply voltage is increased, and the overheating of the electrode causes the two ends of the lamp to be blackened early and the life is shortened. When the power supply voltage is low, the operating current is low due to the low voltage after startup, which is insufficient to maintain the normal operating temperature of the electrode, thereby aggravating the sputtering of the cathode emitting material and shortening the life of the lamp. Therefore, the supply voltage offset range is required to be ±10%%.
3) Try to reduce the number of fluorescent light switches when possible, because fluorescent lamps are the most harmful to the electrodes during the start-up phase, and the general tungsten lamps do not have this disadvantage. In particular, a fluorescent lamp using an inductive ballast is equivalent to a continuous illumination of the lamp for two hours each time the lamp is activated. Users should avoid switching fluorescent lamps frequently if it is not necessary.
4) Ambient temperature also has an effect on the use of fluorescent lamps. Generally, the ambient temperature below 10 °C makes the lamp start difficult, and the optimum environment for the lamp to work is (20-35) °C.
5) Excessive ambient humidity (75%% to 80%%) is also detrimental to the start-up and normal operation of fluorescent lamps. When the humidity is high, the moisture in the air forms a moist film on the surface of the lamp tube, which is equivalent to a resistor bridging between the two poles of the lamp tube, which improves the starting voltage of the fluorescent lamp and makes the lamp start difficult. As the starting voltage is increased, the filament preheating starting current is increased, and the cathode physical loss is increased, thereby shortening the life of the lamp. Generally, the relative humidity below 60%% is the most unfavorable for the fluorescent lamp to work at 75% to 80%.
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