LED Airfield Lighting System Operation and Maintenance (2015) / Chapter Skim
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Pages 42-61
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From page 42... ...
42 C H A P T E R 4 Circuit Configuration LED lighting systems consume less energy and have a longer life than other lighting sources. Because of their low energy consumption, there has been a tendency to increase the number of fixtures on a given circuit to optimize the capacity of the constant current regulator (CCR)
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From page 43... ...
Operation Considerations 43 derived from the NEC Chapter 9 Table 9 value for #8 AWG cable (0.78 ÷ 1,000)
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44 LED Airfield Lighting System Operation and Maintenance Approach 1: Direct Replacement Without Circuit Modifications If the fixtures on this circuit were then converted to LED, the calculation would be as follows: 100 17 3 20,000 0.00078 43.56 2000 680 2680 TL TL TL ( )
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From page 45... ...
Operation Considerations 45 serve one circuit. This method would maintain the existing circuit segmentation plan which could be operationally important; however, it would have a higher cost and would not alleviate any existing space constraints within the airfield lighting vault.
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46 LED Airfield Lighting System Operation and Maintenance there are cable failures in that circuit. This approach allows them to get the lights back on quickly and perform cable repairs or replacement at a more appropriate time.
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From page 47... ...
Operation Considerations 47 what constitutes a "high-intensity" LED system, there appears to be a shift in the industry to move LED AGL circuits to 5-step CCRs. LED Circuit Inrush The FAA conducted a study to determine the effects of LED lighting on the operation of a CCR.
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From page 48... ...
48 LED Airfield Lighting System Operation and Maintenance Heaters in Elevated and In-pavement Fixtures The need to provide heaters for elevated and in-pavement light fixtures in areas prone to snow, sleet, and ice has been an issue since the start of development and implementation of LED light fixtures. Ice and snow can accumulate and adhere to elevated and in-pavement light fixtures obscuring the light output.
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From page 49... ...
Operation Considerations 49 for an LED light fixture is based on temperature, rather than a function of intensity setting (as is the case for an incandescent fixture)
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50 LED Airfield Lighting System Operation and Maintenance fixture manufacturers and additional research have indicated the MTTF of the light fixture includes the heater. The failure tests performed by the manufacturers have been on fixtures with heaters, thus the MTTF of the light fixture is not limited by the heater.
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From page 51... ...
Operation Considerations 51 Fixture Volt-amps (VA) Watt-Hrs/Year Percent Difference Energy Cost L-850D Quartz Halogen 64 46,720 Baseline $2,803.00 L-850D LED W/Heaters 50.8 23,772 50% less than quartz $1,426.00 L-850DA WO/Heaters 18.8 13,724 70% less than quartz 43% less than heaters $823.00 Table 4.
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From page 52... ...
52 LED Airfield Lighting System Operation and Maintenance Monitoring The two advisory circulars on monitoring AGL systems are AC 150/5345-10, Specification for Constant Current Regulators and Regulator Monitors, and AC 150/5345-56, Specification for L-890 Airport Lighting Control and Monitoring System (ALCMS)
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From page 53... ...
Operation Considerations 53 Photometrics and Chromaticity Photometrics Tables 1 and 2 in AC 150/5345-46, Specification for Runway and Taxiway Light Fixtures, indicate the photometric output requirement for in-pavement and elevated AGL fixtures. Each type of light fixture has a specific requirement and curve for photometric output.
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From page 54... ...
54 LED Airfield Lighting System Operation and Maintenance has a horizontal beam ranging from -7° to +7° and a vertical beam ranging from -4° to +13°. The intensity of the 10% curve must be no greater than 10% of the main beam average, or 500 candelas.
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From page 55... ...
Operation Considerations 55 Figure 39. LED fixtures dimming curve for white LED.
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56 LED Airfield Lighting System Operation and Maintenance Figure 41. CIE mixture diagram.
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From page 57... ...
Operation Considerations 57 Figure 42. Color spectrum overlaid on mixture diagram.
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From page 58... ...
58 LED Airfield Lighting System Operation and Maintenance fixtures for blue, white, yellow, and red will appear similar. Because the light color locations may vary for the different types of LEDs used by the manufacturers, the color may vary among different light manufacturers light fixtures.
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From page 59... ...
Operation Considerations 59 Factors to consider when determining ROI compared to non-LED fixtures include • Fixture cost • Energy cost (with and without heaters) • Maintenance cost (lamp replacement labor and materials)
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From page 60... ...
60 LED Airfield Lighting System Operation and Maintenance With MTTF as a large component of ROI, the defining factors that affect MTTF must be evaluated for both LED and incandescent light fixtures. Historically, the discussion of fixture performance has centered on whether the fixture is energized and operating or not.
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From page 61... ...
Operation Considerations 61 Key Takeaways • Develop a maintenance plan that includes cleaning and inspecting the lens and performing photometric testing. • Develop a lens cleaning and/or replacement program.
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