HQI-T Single Ended Compact Metal Halide

Following on from Osram's pioneering introduction of low wattage metal halide lighting with its double ended lamp, it soon became clear that consumers desired an even more compact light source in this series. The logical progression was to adopt a smaller single ended arc tube design. Thorn Lighting had long since been the leader in single ended metal halide lamps having great experience with its short arc CSI and CID products. Osram was of course the leader in low wattage metal halide products, and the two companies worked together to realise the new development.

The result was a new range of 150W and 70W single ended products launched by both companies, with Osram also offering a 35W version.

The arc tube has an ellipsoidal shape in an attempt to create an isothermal design, in which all areas of the surface are at as near a uniform temperature as possible. This ensures higher temperature operation of the metal halide dose and leads to increased efficacy and better colour rendering. The tungsten electrodes are rhenium-doped for good emission, and have transversally coiled tips to reduce the arc gap vs the spacing between the leads of the pinch-seal.

The metal halide system is different from the double ended variant, being based mainly on tin with additions of sodium and thallium iodides. Note the unusually strong brown colour of the tin halide vapours immediately after the lamp is switched off. Colour stability through life remains excellent, owing to the fact that the rate of sodium loss is low. Just like with the double-ended HQI-TS, there is no metal frame wire running alongside the arc tube.
Manufacturer: Osram GmbH
Lamp Power: 75 Watts
Lamp Current: 0.98 Amps
Lamp Voltage: 95 Volts
Cap Type: G12 Steatite
Bulb Type: T-25 T-8 in eighths/inch
Bulb Finish: Clear Quartz
Electrodes: Rheniated Tungsten
Arc Length:
Atmosphere: Ar | Hg (Sn,Na,Tl)Ix Outer: Vacuum
Luminous Flux: 5,200 lm lm (@ 100 hrs)
Luminous Efficacy: 69 lm/W (@ 100 hrs)
Colour Temperature & CRI: CCT: 3000K CRI: Ra 80
Chromaticity Co-ordinates: CCx: 0.428 CCy: 0.389
Rated Lifetime: 6,000 hours 50% survival & 70% flux
Warm-up & Re-strike Time: 4 minutes 10 minutes
Burning Position: Universal
Overall Length: 85 mm 33/8 inches
Light Centre Length: 56mm 21/4 inches
Factory: Spandau, Berlin Germany
Date of Manufacture: April 1987 Date Code: qh3
Original / Present Value:
References: 1) Osram Lichtprogramm 2002.