1993 CEW DAK50/WFL

The interesting lamp presented here is a self-ballasted white sodium lamp made in Japan and marketed by C.E.W. Lighting in North America during the 1990s for commercial and retail lighting applications. This DAK50/WFL is made of different detachable parts, such as a large plastic base that contains the series-connected LC ballast and an electronic ignitor, to which an Iwasaki NHT 50W SDX lamp and a metal reflector are attached. The spun aluminum mirror is also provided with a clear front glass plate that adds some basic protection to the lamp.

The overall system consumes 85 Watts and delivers about 1900 lm in the forward direction, which corresponds to a total lumen efficacy of 22 lm/W. Although this is quite low by HID system standards, this efficacy still compares favorably to the ~10 lm/W of standard incandescent reflector lamps. As a result, the DAK50/WFL was a credible energy-saving lighting product with a good value proposition. However, the advent of infrared-conserving halogen lamps, developed by GE in the early 1980s, and the application of this technology to reflector lamps during the 1990s narrowed the gap in performances between incandescent and white sodium sources. GE’s PAR HIR lamps that resulted from such development where characterized by a lumen efficacy of 21 lm/W, delivered in a more attractive package and for a lower cost price. This eventually precipitated the end of the complex and expensive self-ballasted white sodium reflector lamp.