Experimental "Magnetic Arc-Spreading" compact fluorescent lamp


The energy crises of the 1970s inspired inventors to try novel ideas for new light bulbs. One of the more unusual designs emerged from the drawing board of Manhattan Project veteran Leo Gross. Supported by Merrill Skeist at Spellman High Voltage Electronics Corporation, Gross designed a compact fluorescent lamp that he called a "magnetic arc spreader" (MAS).

The design took advantage of a fundamental aspect of electro-magnetism known since the early 1800s. When a current flows through a coil of wire, it produces a magnetic field. The arc discharge that travels between the electrodes of a fluorescent lamp can be affected by the presence of such a field. In the center of the MAS lamp seen here there is a copper coil. Current moving through the coil creates a magnetic field that spreads out the electrical arc within the lamp. The expanded arc energizes phosphor throughout the lamp's entire length.

The concept was tested at Lawrence Berkeley Laboratory, and General Electric became interested. In 1978 GE purchased a one-year license from Spellman in order to conduct further tests but determined that the necessary glasswork would make the lamp too expensive for commercial production. GE donated one of their test lamps to the Smithsonian in 1998—the only known surviving example of this experimental design.

Lamp characteristics: No base. Two stranded lead-wires extend about 2" from either end, and each end has one lead wire encased in a glass insulating tube. Two coiled tungsten electrodes are mounted in a hollow cylindrical envelope. The exhaust tip is near one set of leads, and the envelope has an internal phosphor coating. A coil of bare copper wire held together with black string is inserted into the center of the envelope. A current passing thru this coil spreads the arc between electrodes so that more of the phosphor is activated.

Date Made: ca 1978Date Made: ca. 1978

Maker: General Electric Corporate Research & Development LaboratoryInventor: Spellman High Voltage Electronics Corp.

Place Made: United States: New York, Hicksville

See more items in: Work and Industry: Electricity, Energy & Power

Exhibition: Lighting a Revolution

Exhibition Location: National Museum of American History

Related Publication: Gross, Leo; Skeist, S. Merrill. Feasibility Claimed for Handy Fluorescent

Credit Line: from General Electric Corporate Research & Development Laboratory

Data Source: National Museum of American History

Id Number: 1998.0050.15Accession Number: 1998.0050Catalog Number: 1998.0050.15

Object Name: discharge lampOther Terms: discharge lamp; Fluorescent

Physical Description: glass (overall material)copper (overall material)tungsten (overall material)Measurements: overall: 8 3/4 in x 3 in; 22.225 cm x 7.62 cm

Guid: http://n2t.net/ark:/65665/ng49ca746a5-8d29-704b-e053-15f76fa0b4fa

Record Id: nmah_751183

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