Canadian Ceramalux C150S56 High Pressure Sodium

This lamp is one of the few HPS products to have been made at the Canadian factory of Westinghouse, but is of essentially the same construction as was employed in American-made Westinghouse lamps of the early 1970's.

A notable feature of the design is the sealing method employed for the arc tube, which employs niobium-1% zirconium end caps both as the electrical feedthroughs and to close the ends of the arc tube. This sealing method was employed in the days when the alumina arc tubes could be manufactured only as straight open-ended tubing, without a reduction in diameter at the ends to facilitate sealing in smaller diameter electrical feedthroughs.

The electrodes are spot-welded to a small tab of niobium inside the cup, and a strip of nickel tape welded to the outside forms the current conductor to the frame of the lamp. Three small indents in the side of the cup form point-contacts with the external surface of the PCA, and initially hold the cup in place by friction.

A coating of the frit sealing glass powder was applied to the inner surface of the niobium-zirconium cup, this being one of the early compositions based on the oxides of calcium, aluminium and magnesium. It is not the most effective seal and many failures at the niobium interface were reported. Several years later Westinghouse improved the bond with a coating of silicon on the niobium. Later modifications allowed this coating to be eliminated by including boric oxide and silica in the frit glass. The final changes came when the monolithic seal was invented, employing PCA with ceramic end plugs through which a thin Nb-Zr tube could be sealed.
Manufacturer: Canadian Westinghouse Company
Lamp Power: 150 Watts
Lamp Current: 1.8 Amps
Lamp Voltage: 100 Volts
Cap Type: E39s/41 Brass + vitrite
Bulb Finish: Clear Lead borosilicate glass
Bulb Type: BT-90 BT-28 in eighths/inch
Overall Length: 211 mm 8 5/16 inches
Light Centre Length: 127 mm 5 inches
Arc Length: 63.6mm 2½ inches
Electrodes: Backwound Tungsten Barium Calcium Tungstate
Atmosphere: Na,Hg | Xe Outer: Hard Vacuum
Luminous Flux: 14,000 lm (@ 100 hrs)
Luminous Efficacy: 93.3 lm/W (@ 100 hrs)
Colour Temperature & CRI: CCT: 2100K CRI: Ra 22
Chromaticity Co-ordinates: CCx: 0.523 CCy: 0.415
Burning Position: Universal
Rated Lifetime: 24,000 hours to 50% survival
Warm-up & Re-strike Time: 3-4 minutes 1 minute
Factory: Trois Rivières, Quebec Canada
Date of Manufacture: March 1974 Date Code C4
Original & Present Value: