plate-type frictional electrostatic generator

plate-type frictional electrostatic generator

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Description (Brief)
People from ancient times knew that rubbing certain materials and then touching something caused a spark. Studying what is called electrostatics laid the groundwork for understanding electricity and magnetism. Natural philosophers, scientists, and instrument makers created many ingenious devices to generate electrostatic charges starting in the 1600s. These machines varied in size and technique but all involved rotary motion to generate a charge, and a means of transferring the charge to a storage device for use.
In the latter 1700s electrical researchers adopted improved electrostatic machines that replaced earlier glass cylinders with a flat glass plate. This increased the machines’ efficiency by passing the glass plate between leather rubbing pads that increased the contact area. Experience with plate machines brought many design variations with sizes ranging from small table-top units for laboratory use to large cabinets that powered early x-ray machines.
This electrostatic machine may have been made by instrument maker Hippolyte Pixii (1808–1835) of Paris. Although referred to as a Ramsden machine, the unit has no direct link to Jesse Ramsden (1735-1800), an early developer of plate machines. According to historian Willem Hackmann, Ramsden’s name became a generic term in France for plate machines.
The machine is similar in appearance to a known Pixii machine in the collection (see catalog #1989.0029.14) but has only a single glass plate. Rotated by turning the crank on the end of the machine, the glass rubs against leather pads generating a static charge that is transferred to the brass frame, known as the prime conductor. The machine was used at the University of Georgia and came to the Smithsonian in 1965.
Currently not on view
Object Name
Electrostatic Machine
electrostatic generator
Other Terms
Electrostatic Machine; Electrostatic Devices
overall: 48 in x 48 in x 24 in; 121.92 cm x 121.92 cm x 60.96 cm
ID Number
catalog number
accession number
Credit Line
from the University of Georgia, thru C. Dewey Cooper
See more items in
Work and Industry: Electricity
Data Source
National Museum of American History
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