Manufacturer: Osram
Model: SOX/H 55W
Application: Streetlighting, Security Lighting
Wattage: 55W
Diameter (max): 50mm (T-50)
Length: 420mm
Tube Length: 60mm Approx 15mm diameter
Bulb/Tube material: Inner, glass, sodium resistant inner coating.  Outer, glass, indium oxide IR reflective inner coating.
Colour Temperature: 1700K - CRI: Ra=0
Peak output wavelength: 589nM
Total light output: Unknown
Rated lifetime: 6000 hours
Cap: B22
Operating voltage: Unknown
Operating current: Unknown
Warmup/restrike time: 10 minutes/none
Cost (original): Unknown
Value (now): Unknown
Place of manufacture: Unknown
Date of manufacture: Unknown
Current Status: Damaged, but working.

You may note that there are a lot of "unknowns" in there.  The main reason for that is that the lamp you see here spent many years in a street light near here, which had long, long since lost its weatherproofing rubber seal - as a result half the lamp was immersed in water - the half which had originally the stamp on it.  So, I have no model number, no date code, no nothing.  Luckily I can tell from the tube structure that it's an Osram product.

You may also note that there's tape wrapped around the neck of this lamp.  The reason that's there is quite simple, and that reason is that the outer envelope of this lamp is cracked.  Quite how that happened I have no idea, I know it happened in the middle of the night, when the lamp was sitting on the desk in here.  I woke up at about four in the morning hearing this "clinking" noise coming from the desk, I turned on the lights, went over, and got there just in time to see the whole outer envelope part company with the base about 10mm up from the clamp.  I crudely taped the thing back together so as to minimise the chances of the inner tube becoming broken.  I may clean it up and glue it back together some day for the sake of cosmetics, then retake the photographs. 

Despite having no vacuum in the outer jacket, the lamp does still operate, and still manages about 85% of its full output, though it does never quite run up fully now.  Obviously, running like that is hard on the lamp electrodes though, so it would probably have failed prematurely if still in situ in this condition.

This was one of three lamps which were my first low pressure sodium examples.  Rescued from an almost certain trip to a skip after some SOX streetlights in a local village were replaced with fluorescent versions (a bad thing I think).  The workman there donated me two fixtures and a random lamp (this one).  Both fixtures contained 35W SOX lamps, one nearly new, one expired.  The working SOX lamp is with a friend just now who has borrowed it to find out whether an SO fixture outside his hotel works or not.  I shall add it here when it is returned.

If you can tell me from the images here what the production date of this lamp is, or can point me towards any details of its electrical characteristics I would be most grateful.  This is a technology I'm still very much learning my way around!


Click Thumbnails for full size images.

This lamp added to the Virtual Display Shelf on the 13th of November 2005 at 01:20.


26th January 2021: Minor changes to page formatting to improve readability on mobile devices.

28th April 2023: Revised Statcounter code to allow for HTTPS operation.

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