Sylvania Tru-Aim Professional - M250 EXZ

During the early adoption of the MR16 lamp into general accent and display lighting, a critical safety issue was identified owing to the not infrequent ocurrence of capsule explosions at end of life. They typically operate with a positive internal pressure of around 10 atmospheres, and if the pinch-seal has not been correctly formed it may cause the capsule to shatter. The resulting shower of hot glass fragments obviously poses a potential risk of fire and/or personal damage.

Sylvania was the world's first manufacturer to offer sealed MR16 lamps, equipped with a front lens to contain the fragments in the event of a capsule explosion. The former Tru-Aim range was completely superseded in 1987 by the sealed Tru-Aim Professional type featured on this page.

In a novel departure from the design of existing facetted reflector lamps, Sylvania opted for a common smooth reflector across the range, the beam angle being controlled by various Lenticuled or Stippled textures on the inner surface of the lens. This was an instant hit with professional lighting designers, thanks to the smooth beam distribution without dark spots and facet images sometimes present in open faced lamps. Furthermore the sealed design allowed Sylvania to switch from the traditional quartz capsule material to much lower cost aluminosilicate hard glass. Hard glass capsules have a still higher risk of explosion, and their use was out of the question with the previous open reflectors. However they are considerably cheaper. Thanks to the lower softening temperature of this glass, capsule production speeds could be increased in excess of 3000 per hour - triple that of a quartz line of the time. Thus the additional cost of Sylvania's sealed design could be completely offset by the lower capsule cost.
Manufacturer: GTE Sylvania
Lamp Power: 50 Watts  
Lamp Voltage: 12 Volts  
Lamp Current: 4.16 Amperes  
Cap Type: GX5.3 Glass base
Bulb Type: MRC-51 MRC-16 in eighths/inch
Bulb Finish: Lenticuled Lens Dichroic Mirror
Filament Type: C-8 Axial single coil
Atmosphere: 25% Argon in Kr HBr-SiH4-PH3
Luminous Flux: 1000 lm (capsule flux)
Luminous Efficacy: 20.0 lm/W (capsule efficacy)
Peak Intensity: 3,000 candelas to half-peak intensity
Beam Distribution: 24.0 to half-peak intensity
Colour Temperature & CRI: CCT: 3050K CRI: Ra 100
Chromaticity Co-ordinates: CCx: 0.444 CCy: 0.406
Rated Lifetime: 3000 hours to 50% survival
Burning Position: Universal  
Overall Length: 48.0 mm 1 7/8"
Light Centre Length: N/A N/A
Factory: Tienen Belgium
Date of Manufacture: 25th November 1987 Date Code 23 125
Original / Present Value: GB 7.71 trade (1987) GB 14.99 (2006)
 
References: 1) GTE Sylvania Brochure "Tru-Aim Professional" August 1987
2) GTE Sylvania UK Lamp Catalogue 1987/88
3) GTE Sylvania UK Price List 1988