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Osram-GEC was the first company to bring HPS technology to Europe, with 15 lamps being set up along a 1450-foot stretch of road outside the factory on East Lane, Wembley in January 1966. They were based on GE's original 400W lamp.
Within two years GEC made a significant design departure from its competitors. A drawback of the original lamps was the difficulty upgrading existing mercury installations. Firstly, the failure of HPS lamps is caused by rising arc voltage over time, so to attain a reasonable life it must start with a lower voltage. To keep power ratings the same as mercury lamps, this requires higher current and new ballasts. Secondly, the control gear is made more complex by the requirement for a high voltage pulse to strike the arc. GEC recognised that if it could make its lamps work on existing mercury control gear it would have a greater market potential, and by doing just that it quickly grew to a dominant force in the HPS business.
GEC developed its lamps with a low arc voltage for long life, but accepted a compromise by allowing lamp power to drop to non-standard ratings when used on existing mercury ballasts. This 310W model was the first of the company's "Plug-In" series, designed for operation on 400W mercury ballasts tapped to 10V above the actual supply voltage. The ignition problem was solved with the development of the internal snap-starter - a bi-metal switch heated by a loop of nichrome wire, arranged in parallel with the arc, which creates an inductive pulse to strike the discharge.
Also of interest in this lamp are the early disc-type niobium seals of the arc tube. One end is blind, while the other contains sodium amalgam in the crimped-off exhaust tube. |
Manufacturer: |
The General Electric Company of England PLC |
Lamp Power: |
310 Watts |
Lamp Current: |
3.2 Amps |
4.4A during starting |
Lamp Voltage: |
110 +20-15 Volts |
1000V ignition |
Cap Type: |
E40s/45 |
Ni plated brass + vitrite |
Bulb Type: |
TD-51 |
TD-16 in eighths/inch |
Bulb Finish: |
Clear |
Borosilicate glass |
Electrodes: |
Backwound Tungsten |
BCT Emitter |
Arc Length: |
90 mm |
31/2 inches |
Atmosphere: |
Inner: Na,Hg | Xe |
Outer: Hard Vacuum |
Luminous Flux: |
27,000 lm (@ 100 hrs) |
25,000 lm (average) |
Luminous Efficacy: |
87.1 lm/W (@ 100 hrs) |
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Colour Temperature & CRI: |
CCT: 2100K |
CRI: Ra 23 |
Chromaticity Co-ordinates: |
CCx: 0.526 |
CCy: 0.418 |
Rated Lifetime: |
6,000 hours |
80% survival, 90% lumens |
Warm-up & Re-strike Time: |
5 minutes |
15 minutes |
Burning Position: |
Universal |
Overall Length: |
292 mm |
111/2 inches |
Light Centre Length: |
175 mm |
67/8 inches |
Factory: |
Shaw, Oldham |
England |
Date of Manufacture: |
October 1969 |
Date Code AK10 |
Original / Present Value: |
AU $41.77 (1972) |
GB £185 (2013) |
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