Osram Double Dulux Low Voltage 13W

In 1984 a huge miniaturisation of compact fluorescent lamps was achieved by mounting a pair of U-tubes side-by-side, to create the Sylvania double-tube design. From the single-tube range of 5, 7, 9 and 13W a double-tube family of 10, 13, 18 and 26W was created. There was no 22W double created from the 11W single, because its length and high voltage would preclude operation even on 220-240V mains.

The double-tube lamps have voltages too high for stable operation in countries with 100-130V mains supplies, which required large and inefficient transformer ballasts. In 1985 Osram and Sylvania therefore introduced this low voltage design. It is based on the same discharge lengths as the single-tube 9W and 13W ratings, but folded again to halve its length. Due to a combination of the reduced discharge tube length plus operation at higher current its voltage is lower, and in fact the same as the single-tube types of same power - they therefore operate on the same ballasts. The same caps are also maintained, but the suffix code -2 is added to denote the wider dimensions of the base just above the lampholder interface. Incidentally, due to the high thermal loading of this 13W lamp, its U-bend is deeper than normal so as to lower the cold spot temperatre in the corners to keep the mercury vapour pressure optimum.

The low voltage double-tube lamps are about 5% less efficient than their high voltage European counterparts. For this reason they began to lose popularity as soon as electronic ballasts became popular, that development removing the upper limitations on discharge voltage and allowing the use of the more efficient European-style high voltage lamps in the Americas.
Manufacturer: Osram Corporation
Lamp Power: 13 Watts (@ 60Hz)
Lamp Current: 0.290 Amps (@ 60Hz)
Lamp Voltage: 56 Volts (@ 60Hz)
Cap Type: GX23-2 PBT
Bulb Type: T-12.4 T-4 in eighths/inch
Bulb Finish: CAT, LAP, YOX phosphors Soda-lime glass
Electrodes: Triple Coil Tungsten Triple carbonate emitter
Atmosphere: Argon + Hg
Luminous Flux: 860 lm @ 100h
Luminous Efficacy: 66.2 lm/W @ 100h
Colour Temperature & CRI: CCT: 3500K CRI: Ra 85
Chromaticity Co-ordinates: CCx: 0.411 CCy: 0.398
Lifetime: 10,000 hours
Warm-up & Re-strike Time: 2 minutes Instant
Burning Position: Universal
Overall Length: 123 mm 47/8 inches
Lighted Area:
Factory: Maybrook, New York U.S.A.
Date of Manufacture: 1991 November Date Code: uY5
Original Value:
References: 1) Osram Catalogue, 1990 US, p.21
2) Osram Catalogue, 1992 US, p.21
3) American Standard ANSI C78.901:2001 for electrical specifications
4) OsramSylvania Website, Timeline of Developments, accessed 2004 and formerly at http://www.sylvania.com/flash/milestones/sylvaniatimeline.swf