The operating characteristics of low pressure and high pressure sodium lamps are briefly compared, and the development of high pressure sodium lamps is discussed in terms of availability of new arc tube materials, which had to be resistant to chemical attacks of sodium vapour at high pressure and temperature, have minimum visible radiation adsorption properties, and be suitable in lamp manufacturing processes. At the time, a high-purity aluminium oxide ceramic had been developed, and this material met these requirements. The components of high pressure sodium lamps and their construction are described as follows:- arc tube, electrodes, seals, gas filling, assembly frame, outer bulb, cap, and getter. Three lamp types are described:- (1) ellipsoidal lamps with diffusing finish - 250w and 400W, (2) clear tubular lamps - 250w and 400w, and (3) reflector lamps - 250w. The illumination characteristics of these lamps are summarized under the headings of light output and efficacy, spectral energy distribution, percent luminosity, c.i.e. Chromaticity, colour temperature, lumen maintenance, and polar distribution. Their electrical characteristics are discussed as follows:- reference data, starting characteristics, re-starting, lamp life, and temperature. It is concluded that their excellent colour rendition, high efficacy, low running costs, good lumen maintenance, and long life make high pressure sodium lamps ideal for motorway and street lighting. /TRRL/

  • Corporate Authors:

    Association of Public Lighting Engineers

    78 Buckingham Gate, Westminster
    London SW1E 6PF,   England 
  • Authors:
    • Schappi, R
  • Publication Date: 1974-6

Media Info

  • Features: Figures;
  • Pagination: p. 102-106
  • Serial:
    • Public Lighting
    • Volume: 39
    • Issue Number: 165
    • Publisher: Association of Public Lighting Engineers

Subject/Index Terms

Filing Info

  • Accession Number: 00096356
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Oct 18 1975 12:00AM