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GE Lucalox LU1000 S52 with Voltage Fuse |
American 1000W 'S52' lamps have an unusually high voltage and are characterised by a very long and slender arc tube. They achieve ~7.5% higher efficacy than European low voltage 1000W lamps and due to the low operating current, electrode life and lumen maintenance is better. The support frame is strengthened while reducing shadowing by using two narrow diameter steel wires, and there is a heat + light-reflective disc in the neck area. Efficacy is further enhanced by a zirconium-aluminium strip to getter hydrogen, in addition to the usual barium getter. A glazed porcelain cap is used to avoid breakdown at the higher ignition voltages.
High voltage HPS lamps like this suffer a unique problem that arcing can occur in the outer bulb if its vacuum should be compromised, or if the arc tube leaks. The power is sufficient to melt the glass stem and burn back into the cap, destroying the lamp holder. A fuse was therefore developed, consisting of a loop of iron or nickel wire around one of the stem leadwires and connected to the other. The optimum spacing is fixed by a small glass tube of low melting point. Should arcing develop, the loop will melt into a bead and fuse to the other lead wire, shorting the lamp and tripping an external fuse. The reason for the second glass tube is to restrict arcing to the loop, not the straight wire, otherwise the molten metal may fail to bridge the stem wires.
| Manufacturer: | General Electric Company U.S.A. | |
| Lamp Power: | 1000 Watts | |
| Lamp Current: | 4.7 Amps | |
| Lamp Voltage: | 220 Volts | |
| Cap Type: | E39s/41 | Ni plated brass + porcelain |
| Bulb Type: | ET-79 | ET-25 in eighths/inch |
| Bulb Finish: | Clear | Lead borosilicate glass |
| Electrodes: | Backwound Tungsten | Ba2CaWO6 Emitter |
| Arc Length: | ||
| Atmosphere: | Inner: Na,Hg | Xe | Outer: Hard Vacuum |
| Luminous Flux: | 140,000 lm (@ 100 hrs) | 126,000 lm (@ 12,000 hrs) |
| Luminous Efficacy: | 140.0 lm/W (@ 100 hrs) | |
| Colour Temperature & CRI: | CCT: 2100K | CRI: Ra 22 |
| Chromaticity Co-ordinates: | CCx: 0.522 | CCy: 0.423 |
| Rated Lifetime: | >24,000 hours | to 50% survival |
| Warm-up & Re-strike Time: | 3-4 minutes | 1 minute |
| Burning Position: | Universal | |
| Overall Length: | 383 mm | 151/16 inches |
| Light Centre Length: | 222 mm | 83/4 inches |
| Factory: | Ravenna, OH | U.S.A. |
| Date of Manufacture: | January 1980 | Date Code: 1 .- |
| Original Value: | Unknown | |
