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Philips 140W SOI/H Lamp The immediate predecessor of the 135W SOX lamp, this 140W SOI/H lamp with its integral outer jacket and the recognisable arc tube dimples was the 2nd generation of SOI/H lamp introduced in 1960 and produced over a relatively short time period of four years, being superseded by SOX in 1964. Note the single insulating glass sleeve over the arc tube, most probably used to avoid infringing the GEC patent of two separate tubes over each leg. Keywords: Lamps

Philips 140W SOI/H Lamp


The immediate predecessor of the 135W SOX lamp, this 140W SOI/H lamp with its integral outer jacket and the recognisable arc tube dimples was the 2nd generation of SOI/H lamp introduced in 1960 and produced over a relatively short time period of four years, being superseded by SOX in 1964. Note the single insulating glass sleeve over the arc tube, most probably used to avoid infringing the GEC patent of two separate tubes over each leg.

20250518_123715.jpg DSC04846.JPG Philips_140W_SOI-H_Lamp.jpg Sam_in_the_corner.jpg A_lovely_pair.jpg
Lamp/Fixture Information
Manufacturer:Philips Gloeilampenfabrieken
Lamp
Lamp Type:Low Pressure Sodium
Filament/Radiator Type:U-shaped arc tube
Base:BY22d, porcelain
Shape/Finish:T65, clear
Service Life:6000 hours
Burning Position:Horizontal ± 20°
Electrical
Wattage:140
Voltage:160
Current:0.9A
Optical
Lumen Output:13,000 lm (@ 100 hrs) 12,200 lm (mean to 4000hrs)
Lumen Efficacy:92.9 lm/W (@ 100 hrs)
Colour Temperature:1700K
Colour Rendering Index:Ra -44
Physical/Production
Dimensions:20¾ inches (525 mm)
Factory Location:Eindhoven, Netherlands
Fabrication Date:November 1962
Application/Use:Street lighting
File information
Filename:Philips_140W_SOI-H_Lamp.jpg
Album name:Ria / Low Pressure Sodium Lamps
Keywords:Lamps
Filesize:209 KiB
Date added:19 May 2025
Dimensions:1523 x 1505 pixels
Displayed:11 times
URL:https://trad-lighting.net/gallery/displayimage.php?pid=856
Favourites:Add to Favourites

Comment 1 to 10 of 10
Page: 1

Sammi   [Mon 19 May 2025 at 18:31]
Definitely a nice addition to the collection.! Love LPS
Tuopeek   [Wed 21 May 2025 at 18:24]
Very nice find. That will be a heavy lamp with all that glass.
Sammi   [Wed 21 May 2025 at 20:20]
It certainly is.! Wonder
Careful handling is definitely required. Mind Blown
Tuopeek   [Wed 21 May 2025 at 22:00]
I think the space was a bit tight for the two glass tube like GEC with the Philips dimples as well.
Ria   [Thu 22 May 2025 at 14:15]
That could well be, but GEC definitely had a patent on the 2 tube design.
wide-lite 1000   [Sat 24 May 2025 at 17:59]
Nice find Ladies !
Sammi   [Sat 24 May 2025 at 23:26]
Thanks, litted pictures will follow. LPS Love
Max   [Sun 25 May 2025 at 09:41]
Nice lamp, Ria! This was not the immediate predecessor of the SOX 135W however, but of the 1st-gen SOX 100W (tin oxide coating), followed then by the SOX 90W (indium-tin oxide coating), both 12,000 lm sources. This is the SOI 200W (21,500 lm), made by Philips only, which eventually led to the SOX 135W (same lumen output). As for the single insulating sleeve, this was not implemented merely to circumvent GEC's patent, but also because that was a simpler (i.e. less expensive) and more effective (better thermal homogeneity with less optical losses) solution.
Ria   [Sun 25 May 2025 at 17:20]
Thanks for the useful information as always, Max LPS
Max   [Tue 27 May 2025 at 16:20]
You're welcome, Ria!

Comment 1 to 10 of 10
Page: 1