Guide: Fluorescent lamps are very simple, generally including lamps, lamp holders, ballasts and other components. It is a must-have skill for our men to repair the lamp. Maybe a male compatriot will be weak and ask a question. I don’t know if the ballast is dry. What should I do if the stuff is broken? Don't worry, let's take a closer look at the principles of electronic ballasts . Be sure to master them. . .
1. Principle of electronic ballast - introduction
The electronic ballast (Ballast) is an electronic control device that converts a direct current or low frequency alternating current voltage into a high frequency alternating current voltage to drive a low pressure gas discharge lamp, a tungsten halogen lamp and the like. It is installed between the power supply and one or several fluorescent lamps to convert the AC voltage of the power supply into a high-frequency AC power, so that the lamp (single or multiple) can be normally started and stabilized.
In the past, fluorescent bulbs were commonly used in fluorescent lamps. The disadvantage is that the illuminating process must rely on self-inductance, so the fluorescent lamp flashes a few times before it normally illuminates. Unlike magnetic ballasts, electronic ballasts rely on internal electronic components to directly apply high voltage across the filaments, breaking down the gas inside the lamp, causing the fluorescent lamp to illuminate. Because the breakdown voltage is high, the fluorescent lamp can be illuminated at the moment the switch is turned on. Therefore, traditional inductive rectifiers are gradually being replaced by increasingly mature electronic ballasts.
2. Electronic ballast principle - working principle
The electronic ballast is a converter that converts a commercial frequency AC power source into a high frequency AC power source. The basic working principle is: the power frequency power supply becomes a DC power supply after passing through a radio frequency (RFI) filter, full-wave rectification and passive (or active) power factor corrector (PPFC or APFC). Through the DC converter, the high-frequency AC power supply of 20K-100KHZ is output, and is applied to the LC series resonant circuit connected to the lamp to heat the filament, and at the same time, the high voltage is resonated on the capacitor, and is applied to both ends of the lamp tube, but the lamp discharge becomes a guide. Passing state, then entering the lighting state, at this time, the high-frequency inductor acts as a limiting current to ensure the lamp voltage and lamp current required for normal operation of the lamp. In order to improve reliability, various protection circuits such as protection, waves are often added. Surge voltage and current protection, temperature protection and more.
The specific working process is as shown in the figure above: the electronic ballast first converts the alternating current of 220 V into a direct current after being bridge rectified. Then the triode oscillating circuit (DC/AC converter) is changed to a higher frequency (generally between 20 and 100 Hz) "approximate square wave alternating current", and then through the circuit choke (equivalent to the inductor town) The coil of the flow device and the relevant circuit power up the two filaments of the lamp (similar to the "preheating process" of the filament), and at the same time, the "resonant capacitance" connected to the filament circuit and the filament form a resonant circuit, so that the lamp is inside The gas is broken down due to the high resonance voltage, and the two ends of the lamp are directly turned on (without passing through the filament loop); at this time, the resonant capacitor is "destroyed" by the direct conduction of the lamp, so it does not form. Resonate and stop "working", at this time the lamp will normally illuminate.
3. Electronic ballast principle - advantages
1) Energy saving. The electronic ballast of the fluorescent lamp is used to supply the lamp with a frequency of 20-60 khz, so that the luminous efficiency of the lamp is increased by about 10% than that of the power frequency (by a length of 4 feet), and the power consumption is low, so that the total of the lamp The input power is reduced by about 20%, which has better energy saving effect.
2) Eliminate stroboscopic light and make the light more stable. It is beneficial to improve visual resolution and improve efficacy; reduce visual fatigue in continuous operation and help to protect eyesight.
3) The starting point is more reliable. After starting the lamp, the starting point is successful and avoids multiple starting points.
4) High power factor. Fluorescent lamps above 25W that meet national standards have a power factor higher than 0.95. However, it should be noted that the national standard specifies a high harmonic limit for lamps below 25W, so that its power factor drops to 0.7-0.8.
5) Stable input power and output luminous flux: High-quality products have good voltage regulation performance. When the power supply and voltage deviation are large, the light source can maintain constant power and stabilize the illumination, which is conducive to energy saving.
6) Extend lamp life. The constant power of the high-quality products and the decrease in the lamp current, as well as the reliability of the starting point, can extend the life of the lamp.
7) Low noise. High-quality electronic ballasts can reach noises below 35db, and people can't feel the noise.
8) It can be dimmed. For places where dimming is required, such as the original dimming of incandescent or tungsten halogen lamps, high-efficiency fluorescent lamps with dimmable electronic ballasts can be used to achieve large-scale dimming from 2% to 100%.
It should be noted that only the well-designed electronic ballast can exert the above advantages. Although they are all electronic ballasts, electronic ballasts for metal halide lamps are much more complicated or almost completely different than those used for fluorescent lamps. If the design or manufacturing process is not in place, a very small omission will cause a malfunction.
The above is a detailed introduction to the electronic ballast, I hope to help everyone. Xiao Bian carefully selected four articles on electronic ballasts, I hope everyone learns and masters. . .
Electronic ballast related articles
Our company specializes in the production and sales of all kinds of terminals, copper terminals, nose wire ears, cold pressed terminals, copper joints, but also according to customer requirements for customization and production, our raw materials are produced and sold by ourselves, we have their own raw materials processing plant, high purity T2 copper, quality and quantity, come to me to order it!
Cable Terminals
Taixing Longyi Terminals Co.,Ltd. , https://www.longyicopperlugs.com