Testing a rare white sodium lamp

This picture shows the power analyzer in action while running a very rare white sodium lamp, the Philips SDW-AR 35W. This lamp was designed, built and tested in the early 1980s with the intention to achieve significant energy saving in existing incandescent lighting installations by replacing the 100 W silver-crown GLS lamp in its reflector luminaire. Such inefficient lighting system was commonly used in shop windows and retail displays back then because of their glare-free illumination. However, Philips never released the silver-crown version of the SDW because of its too specialized application, and opted to push for new lamps and luminaires instead of going for retrofit solutions.