Philips HPI/TD 10,000W
Delivering one million lumens, this is believed to be the most powerful metal halide lamp to have been commercialised for floodlighting applications. It was developed to reduce system costs for the lighting of professional sports stadiums from which colour television broadcasts were to be made. Previously the workhorse of stadium lighting was the 2kW single-ended metal halide lamp. To meet the increased light levels needed with the early colour television camera tubes, it was often necessary to employ over a hundred lamps and the resulting costs were immense. In the 1970s Philips set about developing new 5kW and 10kW lamps to reduce the quantity of luminaires, and increase system efficacy.

The operating principle is essentially the same as the smaller HPI types, being filled with the tri-band chemistry of sodium, indium and thallium iodides, but without outer bulb. The Philips NV72 sealed luminaire was designed around the lamp to perform that role, and the consequent reduction in lamp diameter permitted a gain in optical efficiency. The end seals comprise double parallel molybdenum foils, and these are reinforced mechanically with a secondary quartz tube.

Later it was decided not to launch the 5kW lamp because it was found to be more cost effective to develop a twin-lamp floodlight containing two 2kW lamps, but the larger lamp was introduced around 1972. This particular sample is one of the early prototypes, and by the time of its launch it was re-rated to 9kW. It was used most famously to light the football stadia at Mönchengladbach (Germany), and in England at Everton and Liverpool City, but was rapidly made obsolete. When improved cameras having better sensitivity were developed, the 2kW lamps proved satisfactory.
Manufacturer: NV Philips Gloeilampenfabrieken
Lamp Power: 10,000 Watts
Lamp Current: 23 Amperes
Lamp Voltage: 420 Volts
Cap Type: Cables
Bulb Type: T-46 T-14.5 in eighths/inch
Bulb Finish: Clear Quartz glass
Electrodes: Double Coil Tungsten
Arc Length: 360mm 14 3/16 inches
Atmosphere: (Na,In,Tl)Ix, Hg | NeAr
Luminous Flux: 1,000,000 lm (@ 100hrs)
Luminous Efficacy: 100 lm/W (@ 100hrs)
Colour Temperature & CRI: CCT: ~3600K CRI: Ra ~65
Chromaticity Co-ordinates: CCx: ~0.41 CCy: ~0.41
Rated Lifetime: Unknown
Warm-up & Re-strike time:
Burning Position: Horizontal
Overall Length: 743 mm 29 1/4 inches
Light Centre Length: 128 ± 5 mm 5 1/4 inches
Factory: Eindhoven Netherlands
Date of Manufacture: October 1971 Date Code 1K
Original / Present Value: Unknown
 
References: 1) New Developments in Gas-Discharge Lamps for Outdoor Lighting & Colour TV, L.B. Beijer, Philips Engineering Report 23 c.1970.