White Kelvin-type electrodynamic balance
date: label: date made
content: ca 1889
name: label: maker
content: White, James
notes: label: Description (Brief)
content: Complete with separate weight box. This balance consists of two fixed coils and two movable coils mounted on a balancing arm supported on trunnions above the fixed coils; mounted on a black panel. Marked: "Lord Kelvin's Patents / Electric / 511 / Balance / James White, Glasgow". The electrodynamic forces between the coils, when the current to be measured passes through them, are balanced by adding known weights to the balancing arm, until exact balance is obtained. The value of the weights used is then a measure of the current. This balance is for the measurement of relatively small currents. This form of balance is similar in principle to the Siemens Electrodynamometer, but uses the force of gravity as the means of balancing instead of the spring and torsion head. In both types of instruments, it is difficult to measure currents unless they remain very constant during the balancing operation.
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.313265.01
label: catalog number
content: 313265.01
label: accession number
content: 181342
objectType: label: Object Name
content: Balance, Kelvin
label: Object Name
content: electrical balance
label: Other Terms
content: Balance, Kelvin; Measuring Devices
physicalDescription: label: Measurements
content: overall: 10 in x 25 in x 7 in; 25.4 cm x 63.5 cm x 17.78 cm