GE ConstantColor CMH70/T/U/830/G12
When Philips launched the worlds first commercial ceramic metal halide lamps (CDM) at the end of 1994, this major innovation took the lighting industry by surprise. Fast-track projects were immediately initiated at the major competitors to copy the new technology - which was possible thanks to a patent-interchange agreement between the principal lampmakers, which gave them rights to user the Philips patent. For General Electric, it was logical to set up its technology and manufacturing centre at the former Thorn Lighting factory in Leicester, UK, which it had acquired some years earlier. Thorn had in fact produced the worlds first ceramic metal halide lamp many years earlier in 1981 - but those were not marketed due to ballast-technical problems which had been solved with the Philips breakthrough.

GE Lighting was swift to announce that it would introduce its own variants of the Philips CDM Ceramic Discharge Metal-halide lamps, under the former Thorn name CMH, Ceramic Metal Halide. Early prototypes were shown at the 1995 and 1996 Hannover World Light Shows, but it took over two years before GE was ready to launch its first lamps in 1997. The first type to be launched was this 70W G12-based lamp, along with a 70W double-ended quartz version.

The performance claims are identical to the first Philips 70W lamps, however GE introduced a small improvement in the form of its so-called Housekeeper Seals (after the inventor G.W. Housekeeper), which are visible at the interface between the arc tube body and the protruding end plugs. The glassy frit seals increased the strength of the arc tube to prevent breakage during transit, and also avoided premature arc tube cracking at this location.
Manufacturer: General Electric U.S.A.
Lamp Power: 70 Watts
Lamp Current: 0.98 Amps
Lamp Voltage: 90 Volts
Cap Type: G12 Ceramic + NPB pins
Bulb Type: T-19 T-6 in eighths/inch
Bulb Finish: Clear Quartz
Electrodes: Single Coil Thoriated tungsten
Arc Length: 7.0 mm
Atmosphere: Ar-Kr85|Dy-Ho-Tm-Tl-Na-Ix Outer: Hard Vacuum
Luminous Flux: 6,200 lm (@ 100h)
Luminous Efficacy: 88.6 lm/W (@ 100h)
Colour Temperature & CRI: CCT: 3000K CRI: Ra80+
Chromaticity Co-ordinates: CCx: 0.438 CCy: 0.397
Rated Lifetime: 6,000 hours (to L50F50)
Warm-up & Re-strike Time: 2 minutes (to 80% flux) 5-15 minutes
Burning Position: Universal
Nominal Length: 100 mm 4 inches
Light Centre Length: 56 mm 27/32 inches
Factory: Leicester England
Date of Manufacture: 1997 July Date Code: 91
Original Value: GB £86.91 (1997)
References: 1) GE Lighting Spectrum Lamp Catalogue, 1997/98, UK.
2) GE Lighting Price List, July 1997, UK.
3) GE Lighting Technical Catalogue, December 1996, EU.
4) GE Lighting ConstantColor CMH Brochure, March 1996, EU.
5) GE Lighting CMH Product Leaflet, Hannover Messe 1995 DE.
6) GE Lighting Dialog Magazine, April 1996, EU.
7) Report of Hannover Messe, Ray Molony, Lighting Equipment News (UK), May 1996 p.8.
8) US Patent 5,866,982, Arctube for High Pressure Discharge Lamp, Curt Scott, Chuck Greskovich, Mark Duffy, Eric Coxon, Filed 29 Jan 1996.