GE Lighthouse Halogen - Quartzline Q1000T20BP

This lamp represents a typical modern American lighthouse lamp. It was an early halogen design introduced around 1966, and despite its unusual glass outer bulb it does not appear to have any direct incandescent predecessor. It may have been intended as a brighter and longer life version of the similar incandescent 1200W air beacon, 1200T20/BP.

Its design is very different from European lighthouse lamps. Those typically employed large area filaments intended to approximate the size of earlier oil burners, and ensure compatibility with the huge optical systems of the early lighthouses. This American lamp instead employs a compact coiled-coil axial filament, and was presumably developed for newer lighthouses created after the advent of electrical lighting, which could benefit directly from much smaller and simpler axial filaments having improved rotational symmetry.

The filament is an axial coiled-coil with a single support, pinch sealed into a double-ended quartz halogen capsule. This is supported by nickel straps welded to a pair of heavy nickel-manganese rods clamped into the copper base posts. There is a fuse wire between the lower leadwire and the frame, sheathed in a ceramic tube for safety. The base consists of a pair of copper thimbles, the ends of which are glazed with borax and a glass bead, and Housekeeper-sealed into a pressed glass cup to which the outer bulb is also fused. It was originally made at Mattoon in USA until 1998 when the Bi-Post lamps were reloacted to Leicester in England. When Leicester closed in 2007 it moved again to Kisvarda in Hungary, and at that time was replaced by the Q1000T7/BP lamp having no outer bulb, and a single-ended halogen capsule cemented into a ceramic base.
Manufacturer: General Electric U.S.A. GE #41734
Lamp Power: 1000 Watts
Lamp Voltage: 120 Volts
Lamp Current: 8.33 Amperes
Cap Type: G38 Mogul Bi-Post, copper
Bulb Type: T-63 T-20 in eighths/inch
Bulb Finish: Clear GE772 leaded borosilicate
Filament Type: CC-8 1/4" x 1" Axial Coiled-Coil
Atmosphere: Krypton-Halogen
Luminous Flux: 22,400 lm (initial) 21,700 lm (mean)
Luminous Efficacy: 22.4 lm/W (initial) 21.7 lm/W (mean)
Beam Intensity: N/A
Beam Distribution: N/A
Colour Temperature & CRI: CCT: 3050 Kelvin CRI: Ra 100
Chromaticity Co-ordinates: CCx: 0.452 CCy: 0.409
Rated Lifetime: 3000 hours
Burning Position: Vertical base down
Overall Length: 241.3 mm 91/2 inches
Light Centre Length: 101.6 mm 4 inches
Factory: Leicester England
Date of Manufacture: September 2006 Date Code: 09
Original Value: USD $25.50 (1972)
 
References: 1) GE Spectrum Lamp Catalog, 2006 USA.
2)
3) GE Canada Large Lamp Order Guide, January 1971, p.22.
4) GE Canada Large Lamp Order Guide, June 1966.
5) Hillboro Lighthouse History, citing conversion from 3x 250W to 1x 1000W lamp in 1966