Osram SOX-Plus Extended Life Lamp

The SOX-Plus lamp was launched by Philips in 1993, with its goal being to extend the group re-lamping interval for low pressure sodium installations from two to three years and allow them to compete better with the longer life SON lamp. Very soon afterwards the same improvements were offered in this lamp from Osram, as well as by General Electric.

In terms of construction, SOX-Plus lamps are virtually identical to their predecessors. For a number of years ordinary SOX lamps had been out-performing their life claims, and rather than simply upgrading the specification, Philips cleverly re-marketed them as apparently superior products under the SOX-Plus name. Since longer life claims were advantageous to users, a higher price and greater profits could be commanded. The higher selling price was needed to counter the terms of the longer warranty, since an increase in the number of claims could be expected. After a number of years when this became widely known, the orginal SOX disappeared and was replaced by SOX-Plus.

This Osram lamp makes use of the same red colour cap as the Philips SOX-Plus to indicate its longer claimed lifetime. At the time of its introduction, the discharge tube top support was changed. The former 2-piece metal construction has been replaced by a single-piece component stamped from metal sheet. In parallel the shape of the domed end of the outer envelope has been changed, having a flat shoulder and dimpled end. The new support is mounted against the flat shoulder and cushioned by four small leaf springs formed into the metal support, to effectively absorb thermal expansion of the hot dischage tube without exerting high forces on the outer envelope or mount construction.

Manufacturer:	Osram GmbH
Lamp Power:	37 Watts
Lamp Current:	0.6 Amps
Lamp Voltage:	70 Volts
Cap Type:	BY22d	Alkyde Insulator
Bulb Type:	T-50	T-16 in eighths/inch
Bulb Finish:	Indium-tin oxide film	Soda-lime glass
Electrodes:	CCC-4 Beehive	Black W + BCT emitter
Arc Length:
Atmosphere:	Na \| 99% Ne, 1% Ar	Outer: Hard Vacuum
Luminous Flux:	4,600 lm (@ 100 hrs)	lm (average to 4,000h)
Luminous Efficacy:	lm/W (@ 100 hrs)
Colour Temperature & CRI:	CCT: 1700K	CRI: Ra -44
Chromaticity Co-ordinates:	CCx: 0.574	CCy: 0.425
Rated Lifetime:	12,000 hours	70% survival
Warm-up & Re-strike time:	8-12 minutes	Instantaneous
Burning Position:	Vertical Cap Up ± 110°
Overall Length:	311 mm	16³/₈ inches
Light Centre Length:	mm	inches
Factory:	Shaw, Oldham	England
Date of Manufacture:	February 1996	Date Code: o628
Original / Present Value:	GB £30.90 (1994)	GB £54.89 (2014)


References:	1) Osram SOX Brochure, c. 1995.
	2) Osram Lichtprogramm 2002/2003.
	3) Osram UK Price List, June 2003.