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Philips HP/AB 400W Lead-Gallium Halide Lamp |
It follows the design features of Philips' early HPI metal halide lamps. The arc tube is of somewhat larger volume to achieve optimum efficiency of UV generation. Heat reflective zirconia coatings are present behind the electrodes. The arc tube is mounted in an outer bulb filled with nitrogen to protect the seals and a zirconium getter is present to reduce hydrogen impurities. A P40s pre-focussed cap permits accurate alignment of the arc tube in the optical apparatus.
Incidentally the close-up photo of the pinch seal reveals a curious design feature of early Philips metal halide arc tubes. To attain high purity, the Philips process involves first tipping off the arc tubes with a long exhaust tube, followed by a 40-hour furnacing to bake out impurities. Then they are re-pumped and the exhaust tube short-tipped. This furnacing process was originally carried out in air, which would of course cause oxidation and failure of the moly foil seals. Protection was applied by melting two small quartz tubes over the lead wires of each seal and pumping them to rough vacuum. After furnacing the quartz tubes were cut off, some of the residue can be seen here. The process was labour intensive and a small army of women was employed in attaching, evacuating and removing these tubes. During the 1980s Philips changed to furnacing in an inert atmosphere and the process was abandoned.
| Manufacturer: | NV Philips Gloeilampenfabrieken | |
| Lamp Power: | 400 Watts | |
| Lamp Current: | 3.2 Amps | |
| Lamp Voltage: | 140 Volts | |
| Cap Type: | P40s/45 (Mogul Prefocus) | Ni Plated Brass + Porcelain |
| Bulb Finish: | Clear | Borosilicate glass |
| Bulb Type: | T-51 | T-16 (in eighths/inch) |
| Overall Length: | 290 mm | 11 1/2 inches |
| Light Centre Length: | 178 mm | 7 inches |
| Arc Length: | ||
| Electrodes: | Backwound tungsten | No emitter |
| Atmosphere: | Inner: Hg,PbBr2,Ga2I6 | Ar | Outer: Nitrogen |
| Luminous Flux: | 9,150 lm | measured data |
| Luminous Efficacy: | 22.9 lm/W | measured data |
| Colour Temperature & CRI: | CCT: 9200K | CRI: Ra 35 |
| Chromaticity Co-ordinates: | CCx: 0.290 | CCy: 0.283 |
| Burning Position: | Universal | |
| Rated Lifetime: | Not published | |
| Warm-up & Re-strike Time: | 4 minutes | 15 minutes |
| Factory: | Turnhout | Belgium |
| Date of Manufacture: | May 1980 | Date Code E0 |
| Original & Present Value: | Unknown | |
