2nd Generation Planar Filament - Q2000T11/4CL CYX

In March 1966 GE's engineers made a major development by launching the Q750T20/4CL, the first halogen lamp to feature a planar filament. It was developed to meet the assymetric radiation requirements of studio and theatre lighting equpment, employing fresnel lens and reflector type optics. That first lamp was quickly joined by a larger 2000W version, type Q2000T30/4CL EER, which replaced the earlier 2M/G48 incandescent spotlight lamps DVE, DVF and ECG.

However this double jacketed concept was relatively short lived, and new versions were quickly realised with the naked halogen burner simply mounted on an extended base. The CYX lamp featured here was the first embodiment of the new design. It is interesting to note that this lamp still pre-dates the advent of single ended quartz technology, and employs a double pinched capsule. This has been cemented into an aluminium extension tube which terminates in a porcelain insulator bearing the contact terminals. A fuse is enclosed in the hollow base region. Note also the tensioned filament mount assembly employing molybdenum springs to support the upper end of the filament. This feauture enabled the allowable burning position to be extended from Base Down ±45° to Base Down ±90°.

Incidentally this CYX lamp was not able to immediately supersede its EER predecessor, which employed the same halogen burner in a glass outer jacket. Although the efficacy of both lamps was similar, the life of CYX was three times shorter than EER due to oxidation of its seals. It was not until 1979-82 that CYX underwent a design change to use a single-pinched T10 quartz bulb and its life was extended slightly, that the EER was finally made obsolete.
Manufacturer: General Electric Co. USA Type: Q2000T11/4CL
Lamp Power: 2000 Watts  
Lamp Voltage: 120 Volts  
Lamp Current: 16.67 Amperes  
Cap Type: G38 Ceramic Mogul Bi-post
Bulb Type: T-34.9 T-11 in eighths/inch
Bulb Finish: Clear Quartz
Filament Type: C-13 Planar Grid
Atmosphere: Bromine cycle Argon-15% Nitrogen
Luminous Flux: 59,000 lm
Luminous Efficacy: 29.5 lm/W
Peak Intensity: N/A
Beam Distribution: N/A
Colour Temperature & CRI: CCT: 3200K CRI: Ra 100
Chromaticity Co-ordinates: CCx: 0.423 CCy: 0.399
Rated Lifetime: 250 hours to 50% survival
Burning Position: Base Down ± 90°
Overall Length: 216 mm 8½ inches
Light Centre Length: 127 mm 5 inches
Factory: Cuyahoga Building Cleveland, U.S.A.
Date of Manufacture: February 1975 Date Code 38-
Original / Present Value: Unknown Unknown
References: 1) GE Lamp Catalogue, USA, 1975, p.44