Smithsonian miscellaneous collections, v. 76, no. 2

History of electric light

About the same time Lontin, a Frenchman, improved Serrins arc lamp mechanism by the application of series and shunt magnets. This is the differential principle which was invented by Lacassagne and Thiers in 1855 but which apparently had been forgotten. Several of these lamps were commercially installed in France beginning with 1876. Wallace-Farmer Arc Lamp, 1875. This differentially controlled arc lamp consisted of two slabs of carbon between which the arc played. In the original lamp the carbon slabs were mounted on pieces of wood held in place by bolts, adjustment being made by hitting the upper carbon slab with a hammer. This lamp is in the collection of the Smithsonian Institution. Wallace-Farmer Dynamo, 1875. This was the first commercial dynamo used in the United States for arc lighting. This dynamo is in the collection of the Smithsonian Institution. About 1875 William Wallace of Ansonia, Connecticut, made an arc light consisting of two rectangular carbon plates mounted on a wooden frame. The arc played between the two edges of the plates,35 which lasted much longer than rods. When the edges had burned away so that the arc then became unduly long, the carbon plates were brought closer together by hitting them with a hammer. Wallace became associated with Moses G. Farmer, and they improved this crude arc by fastening the upper carbon plate to a rod which was held by a clutch controlled by a magnet. This magnet had two coils in one, the inner winding in series with the arc, and outer one in shunt and opposing the series winding. The arc was therefore differentially controlled. ......Buy Now (To Read More)

Product details

Ebook Number: 68326
Author: Schroeder, Henry
Release Date: Jun 16, 2022
Format: eBook
Language: English
Publisher: The Smithsonian Institution
Publication Date: 1923
Publisher Country: United States