1980s Philips 13134R/FEX (2000 W / 240 V)

The Philips 13134R is a compact 2 kW double-ended tungsten halogen lamp introduced in the mid-1970s and aimed at studio lighting applications, for a use in highly-efficient luminaires developed for a more accurate control of the emitted light. The lamp is built with a very short (5 cm) coiled coil tungsten filament supported by two sturdy molybdenum coils, held in place by depressions in the quartz tube. The incandescent radiator is designed to emit light with a 3200 K color temperature, ideally suited for TV, color filming and photography using sensitive media (films, sensors) balanced for that particular light color. Because of its high filament temperature, the lamp's mean service life is limited to 250 h only but it enables a high lumen efficacy of 25 lm/W, constant through life thanks to the tungsten halogen cycle. The lamp's oxybromide chemistry is finely tuned and and its delicate balance depends on the cold spot temperature of the quartz vessel (that temperature determines the partial pressure of tungsten oxyhalides around the incandescent filament). As a result the lamp must be kept horizontal within 15° during operation to ensure optimum stability.

The lamp shown here was made at Philips's Turnhout factory in Belgium, which began producing special incandescent light sources in 1957 before becoming the company's HID mother factory in 1979. Production of tungsten halogen lamps there ended around the early 1990s and was transferred to Philips's Aachen and Pont-à-Mousson factories in Germany and France, respectively. The 13134R presented here features a pinched seal pattern that is also found in early Belgian-made high-pressure discharge burners from the 1980s. Because of its high running current (8.3–9.0 A), the tungsten filament wraps the molybdenum lead wires all the way to the thin moly foils that ensure proper air tightness of the end seals. This interesting design has several advantages: the tungsten coil relieve stress in the quartz pinch, which thus prevents the formation of cracks there (note the lack of bulge in that area, typical of early quartz pinch seal designs), and there is no spot weld connection which could cause early filament failure by fracture (most likely at startup when the current peaks) due to large crystal grain formation in the tungsten material at the weld points.

Philips made this lamp type in three voltage variants, i.e., 120, 220 and 240 V. The ANSI reference for the first variant is FEY, while that of the last two high-voltage types is FEX. Due to its thicker filament, the FEY is the most efficacious of the three (28.5 lm/W) and has twice the mean service life rating (500 h). Interestingly, all three models shared the same overall filament length, which allows a usage of all three lamps in the same luminaire. The very compact design of the 13134R was a vast improvement compared to earlier non-halogen incandescent light sources of similar color temperature. The smaller physical size of the halogen lamp allows a placement of the incandescent radiator closer to the projector's optics, which significantly improves the optical control of the emitted light. Optical efficiency was increased further thanks to the short coiled coil filament. While similar optical performances were achievable with some earlier special low-voltage tungsten filament lamps running at high wattages, those required bulky high-current step-down transformers, something not needed with modern tungsten halogen sources of the kind shown here. The downside, however, is a higher risk of non-passive failure due to arcing as a result of filament rupture. To avoid such risk, Philips specified that a rapid acting high-breaking capacity fuse (415 Vac or 500 Vdc type) be used with compact mains voltage high-wattage tungsten halogen lamps.