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1922 - 30,000 watt incandescent lamp, having a capacity of about 60,000 candlepower, the largest lamp of its kind ever manufactured


CD 1964006 E&MP25.061

Electric Lamps

September 24, 1922

A 30,000 watt incandescent lamp, having a capacity of about 60,000 candlepower, the largest lamp of its kind ever manufactured, was shown publicly for the first time at a recent convention of the Illuminating Engineering Society at Swampscott, Mass.

This monster lamp was developed and constructed at the National Lamp Works of the General Electric Company at Cleveland, Ohio, primarily for motion picture studio use. Its wattage is 1,200 times larger than the average household lamp and the electric power required to operate three such lamps would be equivalent power to operate the average trolley car.

This lamp has a bulb 12 inches in diameter and 18-1 inches high. The light which it produces is equal to the combined light from 2,400 electric lamps of the size commonly used in the home. The filament is made of tungsten wire, / inch in diameter and 93 inches long, constructed in four coils. This wire, if drawn into filament wire of the size used in the 25 watt household lamp, would supply filaments for 55,000 such lamps.

Thirteen of these lamps have been made for a motion picture studio in Schenectady, N.Y. where it is claimed the light from these lamps is equal to or the nearest that has yet come to sunlight. It is claimed the advantage of the incandescent over the arc lamp is the absence of the flicker caused by the carbon filaments and the softer tone of light rays. With the carbon arc lamps, the light is more of a ghastly white and does not bring out the color tones so much desired in motion picture production.

These lights are classified as of the Mazda C type, being gas filled. They are lighted from a 120 volt, 250 ampere circuit. Consuming 30 kilowatts, the cost to operate such a lamp, with electric current figured at 10 cents per kilowatt hour, would be $3. per hour.  

Original Caption by Science Service
General Electric

National Museum of American History


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