General Electric current indicator
date: label: date made
content: ca 1893
name: label: maker
content: General Electric Company
notes: label: Description (Brief)
content: This ammeter consists of a black, glass top case. Marked: "Current Indicator / No. 8792 / Capacity 600 Amperes / Patented Oct. 22. 1889 / .General Electric Co. / Thomson-Houston System". This type ammeter was patented in 1889, developed by the Thomson-Houston Co., Lynn, Mass.; however, this particular modal was made at a later date by the General Electric Co. after it was formed by the merging of the Thomson-Houston Co. and others, [in 1892]. The current to be measured passes through a single turn conductor in which is pivoted eccentrically a soft iron movement controlled by gravity. As a result of the eccentricity, the current tends to rotate the iron piece into a position nearer to the conductor, which produces a scale deflection as a measure of the current. In all ammeters of this general ·type it was necessary to bring the entire current to be measured to the switchboard and into the instrument, regardless of its magnitude . This necessity was eliminated and a great saving of copper effected, when the heavy current shunt was developed by Dr. Edward Weston and used with his permanent magnet movable coil type instrument.
label: Location
content: Currently not on view
setName: label: See more items in
content: Work and Industry: Electricity
creditLine: label: Credit Line
content: from Weston Electrical Instrument Corp., thru John H. Miller
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.313278
label: catalog number
content: 313278
label: accession number
content: 181342
objectType: label: Object Name
content: Ammeter
label: Other Terms
content: Ammeter; Measuring Devices
physicalDescription: label: Physical Description
content: wood, glass (case material)
label: Measurements
content: overall: 4 1/4 in x 15 in x 11 in; 10.795 cm x 38.1 cm x 27.94 cm