GE Lucalox LU70/90/D/I/27 with Electronic Ignitor
Since the introduction of the high pressure sodium lamp, the requirement for an external high voltage ignitor has often been regarded as an undesirable system component. This is particularly relevant to the lower wattage lamps where the inclusion of an ignitor in the circuit represents a significant increase in cost, as well as increasing the dimensions of the luminaire that must house it.

During the 1970s a number of low wattage lamps began to appear with built-in ignitors. At first these were based on moving bi-metal strips such as a glowbottle starter or vacuum snap-switch, but for many years both of these techniques suffered reliability problems. Typically the internal starter would fail long before the arc tube reached its end of life. The problem was elegantly overcome with the invention of the FEC internal electronic ignitor, exclusive to Iwasaki's Japanese lamps, but that system is rather costly and was protected by Iwasaki's patents.

This GE lamp introduced a similarly reliable method of starting that circumvented the Iwasaki IP. It employs a small electronic impluse generator, located outside the glass bulb and within the skirted portion of the oversize metal cap. A third leadwire has been pinched into the stem press of the outer bulb, and this carries the pulse via a bi-metallic strip to the arc tube. The bi-metal strip serves to disconnect the ignition circuit when the lamp is hot.

This design was introduced around 1979, and continued in production until the mid 1990s. Thereafter the reliability problems with glowbottle starters were overcome, and the lamp was simplified by reverting to that cheaper concept.
Manufacturer: General Electric Company U.S.A.
Lamp Power: 70 Watts
Lamp Current: 0.98 Amps
Lamp Voltage: 90 Volts
Cap Type: E27s/38x54 Brass + vitrite
Bulb Type: E-75 E-23½ in eighths/inch
Bulb Finish: Diffuse Al2O3 powder Lead borosilicate glass
Electrodes: Backwound Tungsten Ba2CaWO6 Emitter
Arc Length: 34 mm 1.34 inches
Atmosphere: Inner: Na,Hg | Xe Outer: Hard Vacuum
Luminous Flux: 5,800 lm (@ 100 hrs) 5,220 lm (average)
Luminous Efficacy: 82.8 lm/W (@ 100 hrs)
Colour Temperature & CRI: CCT: 1900K CRI: Ra 22
Chromaticity Co-ordinates: CCx: 0.535 CCy: 0.404
Rated Lifetime: 16,000 hours 70% flux & 50% survival
Warm-up & Re-strike Time: 3-4 minutes 5 minutes
Burning Position: Universal
Overall Length: 185 mm 73/8 inches
Light Centre Length: 118 mm 45/8 inches
Factory: Ravenna, OH U.S.A.
Date of Manufacture: July 1990 Date Code: 31 ∙-
Original Value: GB £31.21 (1991)
 
References: 1) General Electric USA Large Lamp Catalogue, Form 9200, 1989
2) GE-Tungsram UK Price List, 1991
3) General Electric USA Brochure, Lampes à Décharge Haute Pression, 6374-482/ILD/F, France, 1980, pp.8 & 14