Wotan Powerstar HQI-R Reflector Lamp
HQI lamps from Osram are metal halide sources designed for operation on ballasts for high pressure sodium lamps. No third auxiliary starting electrode is employed, nor is there any other starting aid, so a high voltage ignitor is required. The reflector bulb version delivers a smooth flood beam, and for many years these lamps were popular in ceiling mounted downlights, for illumination of shop windows and large open areas. In more recent times, since the improvement in luminaire optics, the preference has been for lower wattage lamps combined with higher efficiency external reflectors.

The arc tube is made from three pieces of quartz, consisting of a central large diameter portion with conical end chambers forming the discharge vessel, with a narrow diameter piece of tubing being fused to each end to allow slim pinch-seals to be made. This creates an arc tube whose cold spot temperature is relatively high, leading to better efficacy and colour rendering. The reduced mass of quartz also means it is capable of running up to full temperature, and cooling down to re-striking temperatures more rapidly than traditional one-piece pinched tubes. Heat-reflective coatings of zirconium oxide are applied behind the electrodes, to further raise the cold spot temperature.

This is a neutral white colour lamp containing substantially the same arc tube as found in the tubular formats of the same lamp. It is dosed with the rare earths iodides of dysprosium, holmium and thulium which provide the base spectrum. To bring the colour temperature down to warmer level, sodium iodide is also included. A small dose of thallium iodide produces a green line which dramatically improves the efficacy and brings colour onto the blackbody locus.
Manufacturer: Osram GmbH
Lamp Power: 250 Watts
Lamp Current: 3.0 Amps
Lamp Voltage: 100 Volts For 220/250V circuits
Cap Type: E40s/45 N.P. Brass + Porcelain
Bulb Finish: Inside Frost + Aluminised Borosilicate
Bulb Type: R-125 R-40 (in eighths / inch)
Overall Length: 180 mm 7 1/16 inches
Light Centre Length: N/A N/A
Arc Length: 27 mm 1 1/16 inch
Electrodes: Backwound tungsten Thoriated coil
Inner / Outer Atmosphere: Ar | Hg(Na,Dy,Ho,Th,Tl)Ix Outer:Hard Vacuum
Luminous Flux: 13,500lm @ 100 hours
Luminous Efficacy: 54 lm/W @ 100 hours
Colour Temperature & CRI: CCT:4500K CRI:Ra85
Chromaticity Co-ordinates: CCx: CCx:
Burning Position: VBU ± 150°
Rated Lifetime: 6,000 hours Rated to 50% survival
Warm-up / Re-strike Time: 3-4 minutes 10-15 minutes
Factory: Spandau, West Berlin Germany
Date of Manufacture: May 1987 Date Code qh4
Original / Present Value: £51.45 (1990) £76.18 (2004)
 
References: 1) Osram Lichtprogramm 1988/89.
2) Osram UK Brochure Powerstar HQI - 1990.
3) Osram UK Price List - October 1990.