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Selection of industrial lighting sources

The main criteria for selecting a light source for a specific job include: light efficiency, life, cost (initial installation fee and management fee) and light color. In addition, the size of the light source is also important because it affects the degree of light control. The heat generated by the light source and the heat reaching the work area are also important, and flicker and stroboscopic effects must be avoided. Fluorescent lamps are widely used because they have high light efficiency and long life, making them the most economical lighting equipment. However, the light source is large, so it is more difficult to obtain accurate light control; however, it is also because the light source area is large and the brightness itself is low, so direct glare and shadows can be reduced. High-efficiency lamps have good performance and are suitable for a variety of industrial lighting purposes. However, for occasions where more accurate color discrimination is required, fluorescent lamps with lower light efficiency and better color rendering should be used. Small lamps are suitable for local lighting. The bulbs in enclosed lamps must work at high temperatures, and amalgam lamps should be used. Mercury lamps: Both standard and internal reflective mercury lamps have a fluorescent coating that corrects the light color. Since the use of fluorescent powders that improve light color, the use of mercury lamps has expanded, especially when higher installation heights are required. This lamp has good color rendering and light efficiency, and the light source size is not too large, so the lamp can also be smaller. In polluted air, it is best to use an internal Reflector type mercury lamp. However, to keep the glare at an acceptable level, the bulb must be shielded. Tungsten-ballasted mercury lamps (i.e. self-ballasted mercury lamps) have a longer life and higher light efficiency than incandescent lamps. Unlike arc lamps, they do not require external ballast devices, but use internal incandescent filaments for ballast. This lamp is mainly used to replace incandescent lamps. Metal halide lamps have only been introduced recently. There are now two types of fluorescent powder coated and non-fluorescent powder coated, and their specification range has increased. The light efficiency of the bulb without fluorescent powder coating is high and the light color is moderate; the small-sized light source is suitable for occasions where accurate light control is required. For example, linear lamps are installed in lamps with fan-shaped asymmetrical distribution, which is very suitable for advanced side lighting devices. The light bulb (tube) coated with fluorescent powder is very similar to the light source size of ordinary mercury lamps of the same wattage, but the light efficiency is higher and has better light color performance. Sodium lamps are available in two types: low-pressure and high-pressure. Low-pressure bulbs have high light efficiency, but they are monochromatic and can only be used for special purposes in industry. The recently developed high-pressure sodium lamp has greatly improved color rendering performance. It can be used alone in general lighting inside factories, or in conjunction with high-pressure mercury lamps, especially when the installation height is required to be high. When selecting lamps for factory lighting, its stroboscopic effect must be considered, because this effect will make people feel that the speed of the machine's rotation or reciprocating movement is different from the actual speed. In the worst case, it will make people feel as if the machine is not rotating. Fluorescent tubes with long-lasting fluorescent powder help to reduce the stroboscopic effect. If possible, it is best to connect these lamps that are prone to stroboscopic effects to a three-phase power supply with star connection, where adjacent lamps are connected to different phases. If this is not possible, use the control circuit of the lead-lag fluorescent tube. If high pressure discharge lamps are used, they must be distributed over the three phases of the power supply.