GEC SLI/H Linear Low Pressure Sodium

In 1966 the SOX lamp was put on the market by Philips, employing an advanced new heat-reflective coating of stannic oxide to replace the former glass sleeves. Being equally suitable as an insulator for linear lamps, Osram was the first to adopt this technology and was quick to supersede its Golden Linear lamps with still more efficient offerings with the new tin-based films.

Although the gain in efficiency was only a few percent, the production of stannic oxide lamps was considerably cheaper than for the former gold design. At this time, the GEC also expanded their Linear range to include a 200W rating, directly compatible with the equivalent AEI lamp which was becoming very popular as the most powerful sodium lamp available at the time. Meanwhile, German Osram adopted the use of Bismuth Oxide films in its equivalent products which were available for a very short period only as 60W, 175W and 220W lamps.

As the pioneers of Linear Sodium technology, AEI Lamp & Lighting, which had since become British Lighting Industries and would soon become Thorn Lighting, developed a still more efficient discharge tube with an improved cross-section. While 60W lamps retained the same shape, 140W and 200W lamps adopted a 4-leaf clover section and a new 200W High Output lamp employed a 5-leaf clover type tube. Improved films of indium oxide were applied to the leading 140W and 200W HO lamps, and a xenon component in the gas filling further enhanced efficacy. These innovations secured the company's leadership in Linear technology, a position it retained for the duration of SLI lamp production. This lamp is one the last made, just before closure in 1985.

Manufacturer:	The General Electric Company of England PLC
Lamp Power:	160 Watts
Lamp Current:	0.91 Amps
Lamp Voltage:	210 Volts
Cap Type:	2x G13	Brass
Bulb Finish:	Tin Oxide Film	Soda-lime glass
Bulb Type:	Inner: TD-20	Outer: T-38
Overall Length:	909 mm	36 inches
Light Centre Length:	N/A
Arc Length:
Electrodes:	CCC-4 Black Tungsten	BCT emitter
Atmosphere:	Na \| 99% Ne, 1% Ar	Outer: Hard Vacuum
Luminous Flux:	18,500lm (@ 100 hrs)	18,000 lm (average)
Luminous Efficacy:	115.6 lm/W (@ 100 hrs)	112.5 lm/W (average)
Colour Temperature & CRI:	CCT: 1700K	CRI: Ra-44
Chromaticity Co-ordinates:	CCx: 0.574	CCy: 0.425
Burning Position:	Horizontal ± 5°
Rated Lifetime:	10,000 hours	to 70% survival
Warm-up & Re-strike Time:	12 minutes	Instantaneous
Factory:	Shaw, Oldham	England
Date of Manufacture:	January 1985	Date Code RB
Original & Present Value:	Unknown


References:	1) Osram-GEC UK Catalogue 1985/86.
	2) Osram-GEC Low Pressure Sodium Lamps Brochure, 1976.
	3) Osram-GEC Solarcolour Brochure, 1981.