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Electrical Installation Practice 2. LSEGG304A 9080D. Lighting Concepts 3. Content. Types of high intensity discharge lights Colour rendering of high intensity discharge lights Operating principles of high intensity discharge lights
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Electrical Installation Practice 2 LSEGG304A 9080D
Content • Types of high intensity discharge lights • Colour rendering of high intensity discharge lights • Operating principles of high intensity discharge lights • Control equipment associated with high intensity discharge lights • Efficacy of high intensity discharge lights • Common faults in discharge lights discharge lamps.
High Intensity Discharge Lamps • Mercury Vapour • High Pressure Sodium Vapour • Metal Halide
Mercury Vapour Requires a ballast to limit running current • External • Internal Starting is achieved buy a auxiliary electrode and resistor in the lamp
External Ballasted HPMV Auxiliary electrode Resistor
Internal Ballasted HPMV • High-pressure mercury tube in series with a tungsten filament • Runs on mains voltage without additional gear • Combines a continuous spectrum from the incandescent source and high pressure mercury source
High Pressure Sodium Vapour • Requires a Ballast for control of running current • Ignitor to start the arc in the lamp Some smaller lamps may have an Ignitor incorporated in the lamp
High Pressure Sodium Vapour Contains xenon as well as some mercury • The colour difference between HPS and LPS is due to • Higher gas pressure • Higher temperature • Addition of mercury slightly less than 1 atmosphere 1100°C Pressure Broadening Arc tube is typically made of translucent sintered aluminium oxide. Efficacy 100 lm/W Near the end of their life exhibit a phenomenon known as cycling
Metal Halide Quartz discharge tube containing • high-pressure mercury • Sodium halide • Scandium halides Argon is used to aid ignition.