Osram-GEC 280W Dual Arc Tube SOI/H Lamp

Here is a very rare lamp indeed. It was unique to the GEC range of SOI/H lamps and consists of two separate 140W arc tubes in the same outer envelope. It was intended to give higher light output from existing 140W lanterns, but to run at full power, it required two ballasts and a change of lampholder, so for this and other reasons (fragility, weight, etc.) it didn't prove very popular, and was discontinued in 1969 after 10 years of production.

Lit pictures here. Many thanks to Andy (Photonicinduction) for this lamp, which is believed to be one of, if not the only, fully working example left, certainly in collectors' hands 😎

Sammi has named this wonderful lamp Hugo, after Sir Hugo Hirst of GEC.

Lamp/Fixture Information
Manufacturer:	The General Electric Company of England
Model Reference:	280W SOI/H
Lamp
Lamp Type:	Low Pressure Sodium
Filament/Radiator Type:	Dual U-shaped arc tubes
Base:	UX4 (British 4-pin valve)
Shape/Finish:	T65, clear
Service Life:	6,000 hours
Burning Position:	Horizontal +/- 20°
Electrical
Wattage:	280 (2 x 140W)
Voltage:	2 x 160V (2x 450V ignition)
Current:	2 x 0.9A (2 x 0.81A starting current)
Optical
Lumen Output:	19,000 lm (@ 100h) / 16,800 lm (average)
Lumen Efficacy:	67.9 lm/W (@ 100h) / 60 lm/W (average)
Colour Rendering Index:	Ra -44
Physical/Production
Dimensions:	20¾ in (519 ±10 mm)
Factory Location:	Shaw, Oldham
Fabrication Date:	March 1959 (Date code QC)
Application/Use:	Street lighting
File information
Filename:	GEC_280W_Dual_Arc_Tube_SOI-H_Lamp.jpg
Album name:	Ria / Low Pressure Sodium Lamps
Keywords:	Lamps
Filesize:	218 KiB
Date added:	Aug 26, 2024
Dimensions:	2166 x 1202 pixels
Displayed:	14 times
URL:	https://trad-lighting.net/gallery/displayimage.php?pid=380
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