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Electric Lighting 1 Slide 1. Thomas Edison 2 Slide 2

Jan 03, 2016



  • Electric Lighting

    *Slide 1

  • Thomas Edison *Slide 2

  • Types of Lighting SystemsIncandescent lampsTungsten Halogen LampsFluorescent lampsHigh pressure sodium lampsLow pressure sodium lampsMercury vapourMetal halide*Slide 3

  • Incandescent Lamps*Slide 4

  • Tungsten - Halogen Lamps*Slide 5

  • High Pressure Sodium (HPS) Lamps*Slide 6

  • *Fluorescent LampsSlide 7

  • Metal Halide Lamps*Slide 8

  • Mercury Vapor Lamps *Slide 9

  • Types of Lighting SystemsComparing lamps*Slide 10

    Type of LampLum / WattColor Rendering IndexTypical ApplicationLife (Hours)RangeAvg.Incandescent8-1814ExcellentHomes, restaurants, general lighting, emergency lighting1000Fluorescent Lamps46-6050Good w.r.t. coatingOffices, shops, hospitals, homes5000Compact fluorescent lamps (CFL)40-7060Very goodHotels, shops, homes, offices8000-10000High pressure mercury (HPMV)44-5750FairGeneral lighting in factories, garages, car parking, flood lighting5000Halogen lamps 18-2420ExcellentDisplay, flood lighting, stadium exhibition grounds, construction areas2000-4000High pressure sodium (HPSV) SON67-12190FairGeneral lighting in factories, ware houses, street lighting6000-12000Low pressure sodium (LPSV) SOX101-175150PoorRoadways, tunnels, canals, street lighting 6000-12000

  • Worksheet 1*Slide 11

  • 'Luminous Flux' Part 2*Slide 12

  • Worksheet*Slide 13

  • Part 3 Lighting distribution *Slide 14

  • Designing Sheet*Slide 15

  • Conclusion Questions worksheet 3*Slide 16

  • Thank you for your attention*Slide 17

    *A general group of lamps consisting of mercury, metal halide, high pressure sodium, and low pressure sodium lamps are referred to as high intensity discharge or HID lamps. In these lamps an arc passes between two electrodes in a pressurized tube causes various metallic additives to vaporize and release large amounts of light.The next slides discuss each type of lamp individually*An incandescent lamp acts as a grey body that selectively emits radiation with most of it in the visible region. The bulb contains a vacuum or gas filling. Although this stops oxidation of the tungsten filament, it will not stop evaporation. With an inert gas filling, the evaporation will be suppressed, and the heavier the molecular weight, the more successful it will be. Gas filled lamps normally incorporate fuses in the lead wires. A small break can cause an electrical discharge, which can draw very high currents. As filament fracture is the normal end of lamp life it would not be convenient for sub circuits fuses to fail.The features include an efficacy of 12 lumens per watt; the color rendering index 1A, warm color temperature; and a lamp life of 1 to 2000 hours.*Fluorescent lamps are about 3 to 5 times as efficient as standard incandescent lamps and can last about 10 to 20 times longer.Passing electricity through a gas or metallic vapour will cause electromagnetic radiation at specific wavelengths according to the chemical constitution and the gas pressure. The fluorescent tube has a low pressure of mercury vapour, and will emit a small amount of blue-green radiation. The inside of the glass wall has a thin phosphor coating, selected to absorb the UV radiation and transmit it in the visible region. This process is approx. 50% efficient. Fluorescent tubes are hot cathode lamps, since the cathodes are heated as part of the starting process. The cathodes are tungsten filaments with a layer of barium carbonate. *Mercury vapor lamps are the oldest style of HID lamp.Consists of:Arc tube contains 100 mg mercury and argon gas, the envelope is quartz. No cathode pre-heatingThird electrode with shorter gap to initiate discharge. Third electrode means control gear is simpler and cheaper to makeOuter phosphor coated bulb that provides additional red light using UV, to correct the blue/green bias of the mercury discharge.The outer glass envelope prevents UV radiation escapingAlthough they have long life and low initial cost, they have poor efficacy and exude a pale green color. This and because they contain mercury, makes it best to avoid them by using other types of HID or fluorescent sources that have better efficacy and color rendering. Features include an efficacy of 50-60 lumens per watt, a Color Rendering Index of 3; an intermediate color temperature; a lamp life between 16000 to 24000 hours with a poor lumen maintenance. .*

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