NOTE: I AM PRESENTLY LOOKING FOR A BALLAST FOR THIS LAMP.
Manufacturer: Iwasaki
Model: Eye NHT150SDX
Application: Specialist
Ballast type: Electronic - Custom made by Iwasaki for SDX Range.
Wattage: 150W
Diameter (max): 40mm
Length: 145mm
Electrode gap: 40mm
Bulb/Tube material: (Inner) Polycrystalline Alumina.  (Outer) Glass
Colour Temperature: 2500K
Peak output wavelength: N/A - Broadband Emission
Total light output: 7800Lm (Initial)
Luminous Efficiency: 50-60Lm/W
CRI: Ra 89
Rated lifetime: 9'000 Hours
Cap: E27
Operating voltage: 100V
Striking voltage: Not Stated
Operating current: 1.5A
Warmup/restrike time: Not Stated
Cost (original): Unknown
Value (now): Unknown
Place of manufacture: Saitama Plant, Tokyo - Japan
Date of manufacture: Unknown - Estimate Q4 2004.
Notes: The SDX Range from Iwasaki have for some time now been known as the highest quality sodium based light sources available; offering light virtually indistinguishable from halogen incandescent - yet with very considerably higher efficacies being achievable.

Taking a quick peak at the innards of the lamp here shows the phenomenal attention to detail which Iwasaki are renowned for.  The mechanical construction of the lamp itself, right from the outer bulb to the spring braces on the leadframe, are all totally and completely flawless.  It also shows how high a level the engineering is - with Iwasaki's unique Plasma Sealing technology used - whereby the tips of the niobium tubes which enter the PCA arc tube are melted over and sealed - you guessed it - using a plasma torch of some kind.  Small ceramic heat insulating "cups" sit on each end of the arc tube, to help maintain the sodium amalgam at the correct temperature, and keep the sodium vapour pressure high.

A White SON lamp is essentially just a high pressure sodium lamp where the vapour pressure is increased still higher - causing the spectra to broaden.  Which is what was the main method used by Iwasaki on the predecessor to this range of lamps.  The SDX range were made still more efficient and the CRI was increased still further by the use of a dedicated range of electronic ballasts.

A further advantage of these lamps is that they emit very little UV, and are completely safe for use in open fixtures.  The downside however, is that until quite recently, Iwasaki's ballast design was a closed standard - which meant that they were the only company you could buy one from - which needless to say, could push the overall system cost up considerably.  Their patent expired recently however, so SDX ballasts are starting to become more widely available.

Click the Thumbnails for full size images:



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References:

Datasheets from Iwasaki Electric Company Website

Most of my background knowledge of White SON lamp technology learned from Lamptech