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This lamp is representative of Osram's fourth generation of rare earth metal halide lamp, and was introduced in the mid 1980s. Many aspects of its construction are similar to the third generation design, although this particular lamp is optimised for vertical burning whereas the 3rd generation lamp featured on this website is the equivalent model for horizontal burning. The main difference between the two is in the filling of the arc tube - the horizontal model being dosed with slightly less mercury and modified halide chemistry to account for the more significant upward bow of the arc, whose increased length would otherwise cause a rise in lamp voltage and power dissipatation, with a consequent negative impact on lifetime and colour.
The main technical step forward with this 4th generation lamp is the inclusion of a new gettering system, which combines two distinct kinds of getter. Osram's 1st and 2nd generation lamps employed only a barium getter, and its lack of sorption of hydrogen impurities led to rather short life - these lamps being especially sensitive to hydrogen contamination which causes an increase in the re-ignition voltage of the discharge on each half-cycle of the mains. The 3rd generation lamps introduced a zirconium-aluminium getter but eliminated the barium film, which removes many other gases. That led to a small decrease in lamp efficacy owing to heat conduction loses in the outer bulb, and a lowering of arc tube temperature and halide vapour pressure. This 4th generation lamp employs both getter materials together. During the late 1990s it was replaced by a new single getter which sorbed both hydrogen as well as other gases, and the barium film could then be finally eliminated. |
| Manufacturer: |
Osram GmbH |
| Lamp Power: |
360 Watts |
| Lamp Current: |
3.5 Amps |
| Lamp Voltage: |
120 Volts |
| Cap Type: |
E40s/45 |
Ni plated brass + porcelain |
| Bulb Type: |
T-46 |
T-14½ in eighths/inch |
| Bulb Finish: |
Clear |
Borosilicate |
| Electrodes: |
Backwound Tungsten |
No emitter |
| Arc Length: |
48 mm |
1 7/8 inch |
| Atmosphere: |
DyI3,TlI,CsI | Ar:Kr85 |
Outer: Hard Vacuum |
| Luminous Flux: |
28,000 lm |
@ 100 hours |
| Luminous Efficacy: |
78 lm/W |
@ 100 hours |
| Colour Temperature & CRI: |
CCT: 5900K |
CRI: Ra 85 |
| Chromaticity Co-ordinates: |
CCx: 0.330 |
CCy: 0.365 |
| Rated Lifetime: |
6,000 hours |
to 70% flux |
| Warm-up & Re-strike Time: |
2 mins to 80% flux |
10-15 minutes |
| Burning Position: |
Vertical ± 45° |
| Overall Length: |
285 mm |
111/4 inches |
| Light Centre Length: |
175 mm |
67/8 inches |
| Factory: |
Spandau, Berlin |
Germany |
| Date of Manufacture: |
March 1988 |
Date Code: qa3 |
| Original / Present Value: |
£55.21 (1988) |
£102.31 (2005) |
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