General Electric current indicator

Description (Brief):

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 ┬Ětype 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.

Date Made: ca 1893

Maker: General Electric Company

Location: Currently not on view

See more items in: Work and Industry: Electricity

Exhibition:

Exhibition Location:

Credit Line: from Weston Electrical Instrument Corp., thru John H. Miller

Data Source: National Museum of American History

Id Number: EM.313278Catalog Number: 313278Accession Number: 181342

Object Name: AmmeterOther Terms: Ammeter; Measuring Devices

Physical Description: wood, glass (case material)Measurements: overall: 4 1/4 in x 15 in x 11 in; 10.795 cm x 38.1 cm x 27.94 cm

Guid: http://n2t.net/ark:/65665/ng49ca746a5-2669-704b-e053-15f76fa0b4fa

Record Id: nmah_710147

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