Thomson-Houston Spherical Arc-Light generator
date: label: Date made
content: ca 1887
name: label: maker
content: Thomson-Houston Electric Company
notes: label: Description (Brief)
content: No extant maker's markings. This specimen is an industrial-type spherical arc light machine developed commercially by the Thomson-Houston Co. Sixteen iron bars are used as cross pieces in the frame assembly. Field coils are symmetrically circular and have cup shaped poles. This is a constant current, series-wound device, with a three-layer spheroid armature. The brush assembly is missing from this specimen. A pulley wheel is mounted on the commutator side of the shaft. Two terminal posts on top of the frame have a sliding base, suggesting an arrangement for regulating the strength of the field. The oil cup assembly is also missing. An additional coil appears to be wound near the field magnet winding. This generator was powered by a water wheel (catalog number 316736) and had been installed about 1890 for residential lighting in the home later owned by the donor. Reference: MacLaren, Rise of the Electrical Industry in the 19th Century, page 121, illustration opposite page 116. Also, Electrical World, July 23, 1887, page 11.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from John Daniels
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.316737
label: catalog number
content: 316737
label: accession number
content: 225634
objectType: label: Object Name
content: electrical generator
physicalDescription: label: Measurements
content: overall: 16 in x 22 1/2 in x 31 in; 40.64 cm x 57.15 cm x 78.74 cm
label: Measurements
content: overall: 18 in x 24 in x 24 in; 45.72 cm x 60.96 cm x 60.96 cm