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GEC SuperSOX 55W |
Whereas the dimples are essential for good performance with Philips lamps, Osram-GEC discovered that it was able to eliminate them due to the different nature of its IR coating process. Philips lamps have a relatively uniform IR coating thickness along the length of the lamp, and since the electrode-end of the discharge tube runs hotter than the U-bend this leads to a thermal gradient. The dimples are effective in avoiding the distillation of sodium from the hot end to cold. Meanwhile the GEC coating process achieves a graded film, and by arranging the thicker coating around the bend the root cause of sodium migration is solved.
When this was discovered, the GEC's 2nd generation indium SOX lamps were re-launched under the "SuperSOX" brand. The company extolled the virtues of its more robust dimple-free construction, and ring-shaped sodium reservoirs were added to the periphery of the U-bend to keep the main body of the discharge tube free of light-blocking sodium mirrors. However, the less uniform sodium distribution did lead to longer run-up times. Around this time the top support clip was redesigned with a stronger construction in which the former mica support discs were replace with a small steatite tube passing through the U-bend. Thermal insulation of the bend area was also enhanced by the addition of a large heat-reflective disc of mica.
| Manufacturer: | The General Electric Company of England PLC | |
| Lamp Power: | 55 Watts | |
| Lamp Current: | 0.9 Amps | |
| Lamp Voltage: | 109 Volts | 410V Ignition |
| Cap Type: | BY22d | Mycalex 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: | 7,650 lm (@ 100 hrs) | 7,500 lm (average to 4,000h) |
| Luminous Efficacy: | 139.1 lm/W (@ 100 hrs) | |
| Colour Temperature & CRI: | CCT: 1700K | CRI: Ra -44 |
| Chromaticity Co-ordinates: | CCx: 0.574 | CCy: 0.425 |
| Rated Lifetime: | >6,000 hours | 50% survival |
| Warm-up & Re-strike time: | 15 minutes | Instantaneous |
| Burning Position: | Vertical Cap Up ± 110° | |
| Overall Length: | 415 ± 10 mm | 163/8 inches |
| Light Centre Length: | 235 mm | 91/4 inches |
| Factory: | Shaw, Oldham | England |
| Date of Manufacture: | April 1978 | Date Code: KD |
| Original / Present Value: | Unknown | |
