In this study the effects of voltage changes on beam patterns of low-beam headlamps was evaluated. Seven different types of filament lamps were tested. The voltages used were 12.0, 12.8 and 13.5V. The photometry was performed from 20 degrees left to 20 degrees right, and from 5 degrees down to 5 degrees up, all in steps of 0.5 degrees. The main finding of this study is that, for all seven lamps tested. voltage changes between 12.0V and 13.5V caused light output to change by the same proportion throughout the beam pattern. Therefore, for filament lamps, it is reasonable to use a single constant for all values in a beam pattern when converting a headlighting specification at one voltage to a specification at a different voltage, at least if the voltages in question are between 12.0V and 13.5V. The constants obtained across the seven lamps tested were similar to each other. Furthermore, these constants were in general agreement with the constants derived using the standard IES formula relating light-output changes to voltage changes. Fuller work on this subject is published as a University of Michigan Transportation Research Institute Report UMTRI-98-27.

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    Chartered Institution of Building Services Engineers

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  • Authors:
    • Flannagan, M J
    • Traube, E C
    • Miyokawa, T
    • Sivak, M
  • Publication Date: 1999


  • English

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  • Accession Number: 00767228
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Aug 6 1999 12:00AM