GE Lucalox E-Z Lux LUH215 Mercury Retrofit HPS
At first HPS lamps were excluded from mercury installations, due to their unusual electrical characteristics. The narrow wall-stabilised discharge is cooled by the tube wall, leading to high reignition voltage on each ½-cycle. They also suffer voltage rise during life, due to sodium loss and arc tube blackening which influences amalgam temperature. When lamp voltage exceeds the supply, it will fail by extinguishing, cooling, then cycling on and off. To achieve a long life, HPS voltage is set about 25% lower than mercury - which necessitates a higher current for a given power, and hence different ballasts. A higher striking voltage is also required.

In 1973 Philips introduced the SON-H retrofit with Ne-Ar fill and an auxiliary ignition electrode. It had a high voltage to operate on mercury ballasts, and as such life was short. Due to the different power factor of sodium vs mercury arcs, it delivered a small energy saving. Also in 1973, Sylvania launched its Unalux lamp, having a different amalgam ratio to solve the Philips problems by lowering arc voltage to increase life.

GE's first variant appeared in 1975 as the Lucalox E-Z Lux LUH150, replacing 175W mercury. In 1977 it was joined by this 215W and a 310W to replace 250W & 400W mercury, with 110W & 75W retrofits for 125W & 80W appearing before 1980. In GE lamps the auxiliary electrode takes the form of a bi-metal strip which opens when hot to reduce its electric field and sodium loss. Efficacy is about 15% less than ordinary HPS lamps because thermal losses are higher with Ne:Ar than Xe fills, and life is also reduced due to the higher initial voltage. However a 10% energy saving and 75% increase in luminous flux is possible vs mercury lamps.
Manufacturer: General Electric Company U.S.A.
Lamp Power: 215 Watts
Lamp Current: 2.1 Amps
Lamp Voltage: 130 Volts
Cap Type: E39s/41 Brass + vitrite
Bulb Type: ED-90 ED-28 in eighths/inch
Bulb Finish: Clear Lead borosilicate glass
Electrodes: Backwound Tungsten Ba2CaWO6 Emitter
Arc Length: 70 mm 2¾ inches
Atmosphere: Inner: Na,Hg | NeAr Outer: Hard Vacuum
Luminous Flux: 19,000 lm (@ 100 hrs) 17,100 lm (average)
Luminous Efficacy: 88.4 lm/W (@ 100 hrs)
Colour Temperature & CRI: CCT: 1800K CRI: Ra 20
Chromaticity Co-ordinates: CCx: 0.516 CCy: 0.408
Rated Lifetime: 12,000 hours to 50% survival & 90% flux
Warm-up & Re-strike Time: 4 minutes 4 minutes
Burning Position: Universal
Overall Length: 233 mm 9 inches
Light Centre Length: 131 mm 5 inches
Factory: Ravenna, OH U.S.A.
Date of Manufacture: February 1988 Date Code: 2 ∙-
Original Value: Unknown
 
References: 1) US Patent 3,872,340, High Temperature Lamp Starting Aid, B.R.Collins (General Electric), filed May 1974
2) General Electric USA Large Lamp Catalogue, Form 9200, 1988
3) General Electric USA Brochure, High Intensity Discharge Lamps, TP107-R, USA, 1975, p.35
4) General Electric USA Brochure, Lampes à Décharge Haute Pression, 6374-482/ILD/F, France, 1980, pp.8 & 14
5) GE Introduces additional Lucalox E-Z Lux Mercury Retrofits, Lighting Design & Application, April 1977, p.42
6) Lighting Progress 1977, Lighting Design & Application, December 1977, p.12