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Sylvania Mercury-Tungsten Reflector Sunlight 'RS' |
At its heart is a high pressure mercury-quartz discharge tube based on the Sunlight S-4 ultraviolet lamp, combined with a tungsten filament which performs the dual role of electrically ballasting the arc tube and providing the therapeutic benefit of infrared radiation. That concept had originally been pioneered by GE's German affiliate, Osram, which had introduced its self-ballasted Ultra-Vitalux lamp in 1937. GE combined that with the convenience of a reflector bulb made of UV-B transmitting glass.
In order to allow reliable ignition on the lower 120V mains, a small filament is provided inside the arc tube to create a source of electrons, and this is preheated for a few seconds and then disconnected by a bi-metal switch that is heated by the main ballast filament.
The Sylvania lamp improved the mixing of the infrared from the filament and the ultraviolet from the arc by changing from a single-coil filament situated well beyond the focal point of the reflector, to a coiled-coil filament whose position is brought much closer to the centre of the arc. Another problem with the early RS lamps was the tendency for the mount assembly to shift off-centre during transportation damage, resulting in a non-uniform beam. The Sylvania RS design employs an unusually shaped RT-40 glass bulb whose large protruberance from the front provides robust support for the internal assembly.
| Manufacturer: | GTE Sylvania | ||
| Lamp Power: | 275 Watts | ~105W in arc | |
| Lamp Current: | 2.5 Amps | 3.2A during starting | |
| Lamp Voltage: | 115-125 Volts | ||
| Cap Type: | E26s/25 | Brass + vitrite | |
| Bulb Type: | RT-125 | RT-40 in eighths/inch | |
| Bulb Finish: | Inside Frosted | #776 borosilicate glass | |
| Electrodes: | Tungsten Coil | Double carbonate emitter | |
| Atmosphere: | Hg | Ar | Outer: Argon-Nitrogen | |
| Luminous Flux: | 3050 lm | 9.1 Wrad 380-800nm | |
| Luminous Efficacy: | 11.1 lm/W | ||
| Colour Temperature & CRI: | CCT: 5250K | CRI: Ra17 | |
| Chromaticity Co-ordinates: | CCx: 0.340 | CCy: 0.385 | |
| Ultraviolet Flux in Beam: | UV-A: 25.5% - UV-B: 12.5% - UV-C: 0.09% | ||
| Beam Distribution | 50° | to half peak intensity | |
| Rated Lifetime: | 300 hours | 1200x 15-minute cycles | |
| Warm-up & Re-strike Time: | 3 minutes | 5 minutes | |
| Burning Position: | Universal | ||
| Overall Length: | 191 mm | 71/2 inches | |
| Light Centre Length: | N/A | ||
| Factory: | Manchester, N.H. | U.S.A. | |
| Date of Manufacture: | 1966 March | Date Code: 6308 | |
| Original Value: | US$9.95 | (1968) | |
