GE Lighthouse Incandescent - 250T14/1

Whereas dedicated lamps were developed for lighthouses in many regions of the world, it appears that in North America it was originally preferred to use standard 'floodlight' lamps. These typically employed spherical glass bulbs and highly concentrated bunch-type filaments, slightly more highly loaded than ordinary incandescent lamps, to deliver increased output with 800 hours life. They are generally equivalent to the British Class B/1 Floodlighting lamps.

The first known mention of a dedicated Lighthouse lamp in the American literature can be found in the GE 1956 catalogue, type 1MT20/5, employing two C-5 filaments to create a full ring of light and having similar construction as the British cylindrical filament lighthouse lamps. This appears not to have been successful and was delisted prior to 1966, with the only other dedicated lighthouse lamp until 1971 being the Halogen Q1000T20/BP.

Th low wattage 250T14/1 featured on this page appears to have been introduced in the early 1970s, and has substantially identical construction to the earlier 250W floodlight lamps - the only apparent change being the shift to a tubular glass bulb. Some early American lighthouses are known to have made use of three of the earlier spherical floodlight lamps to achieve the necessary light output, while maintaining a backup in case one lamp should fail. One reason for the introduction of this tubular bulb version may have been to allow the multiple lamps to be positioned more closely together. Being the only known lamp to use a T14 diameter glass bulb, it may have been rather inconvenient to produce, and this type was delisted by GE between 1991 and 1993.
Manufacturer: General Electric U.S.A. GE #22524
Lamp Power: 250 Watts
Lamp Voltage: 120 Volts
Lamp Current: 2.08 Amperes
Cap Type: E26s/25 Brass & Vitrite
Bulb Type: T-14 T-44.5 in eighths/inch
Bulb Finish: Clear Soda-lime silicate
Filament Type: C-5 Bunch
Atmosphere: Argon-Nitrogen P3N5 getter
Luminous Flux: 3,750 Lumens
Luminous Efficacy: 15.0 Lumens per Watt
Beam Intensity: N/A
Beam Distribution: N/A
Colour Temperature & CRI: CCT: 2900 Kelvin CRI: Ra 100
Chromaticity Co-ordinates: CCx: 0.444 CCy: 0.406
Rated Lifetime: 800 hours
Burning Position: Vertical base down
Overall Length: 140 mm 51/2 inches
Light Centre Length: 76.2 mm 3 inches
Factory: Bellevue, OH U.S.A.
Date of Manufacture: September 1971 Date Code: . 53
Original Value: US $5.80 (1972)
 
References: 1) GE USA Large Lamp Catalog, 1956, p.46.
2) GE USA Large Lamp Catalog & List Prices, Form 9200, 23-Feb-1972, p.26.
3) GE USA Large Lamp Catalog, Form 9200, 1991-92, p.35.
4) GE USA Large Lamp Catalog, Form 9200, 1993 - this lamp type delisted.
5) Hillboro Lighthouse History, citing original electrification with 3x 250W lamps in 1932, and upgrade to single 1000W lamp in 1966.