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Osram NAV-E 70W/NB for City of Leipzig |
The cause is believed to have been due to greater design tolerances with old East German ballasts and ignitors, plus harmonisation of European mains voltages from 220V±6% and 240V±6% to 230V±10%. The wider mains tolerance meant that in many regions there was no actual change, but in others where the electricity grid required upgrading, the average voltage did increase, and caused a power increase in lamps. Perhaps because Narva lamps had not been so highly optimised as foreign types, and may have had slightly cooler-burning arc tubes and/or lower xenon fill pressures, they were able to tolerate the elevated powers and strike on weaker ignitors. But for Osram and Philips it was a disaster.
In 1992 Osram solved the problem with the launch of this NAV-E 70W/NB lamp, where NB = Neue Bundesländer, or New Federal States. It was sold exclusively in former DDR territories and features a reduced arc voltage, such that when driven at increased currents the lamp power does not rise too high and it meets its life claim. If driven at standard IEC ballast conditions, it only achieves 53W. It also appears to strike more easily than the standard model. During 1993-94 Philips briefly offered an equivalent 'SON-G' for Germany. Osram maintained its production until as late as 2007, by which time the older control gear had been replaced and there was no longer a need for this highly unusual lamp.
| Manufacturer: | Osram GmbH | |
| Lamp Power: | 70 Watts | |
| Lamp Current: | 1.2 Amps | |
| Lamp Voltage: | 73 Volts | |
| Cap Type: | E27/27 | Ni plated brass + Vitrite |
| Bulb Type: | E-70 | E-22 in eighths/inch |
| Bulb Finish: | Calcium Pyrophosphate | Soda-lime glass |
| Electrodes: | Backwound Tungsten | BCT emitter |
| Arc Length: | ||
| Atmosphere: | Inner: Na,Hg | Xe | Outer: Hard Vacuum |
| Luminous Flux: | 5600 ℓm | |
| Luminous Efficacy: | 80 ℓm/W | |
| Colour Temperature & CRI: | CCT: 2000K | CRI: Ra 20 |
| Chromaticity Co-ordinates: | CCx: 0.526 | CCy: 0.418 |
| Rated Lifetime: | 18,000 h | to 50% survival |
| Warm-up & Re-strike Time: | 5 minutes | 5 minutes max. |
| Burning Position: | Universal | |
| Overall Length: | 156 mm | 41/8 inches |
| Light Centre Length: | 104 mm | 23/4 inches |
| Factory: | Berlin Werk-SB | Germany |
| Date of Manufacture: | 2003 Feb | Date Code: q328 |
| Original Value: | Unknown | |
