direct current dynamo
Datecirca 1875
Inventory Number1997-1-1239
ClassificationElectromagnetic Generator
Subject
Maker
Breguet FT
1870 - 1881
Inventor
Zénobe T. Gramme
1826 - 1901
Maker
Jules Célestin Jamin
1818 - 1886
Cultural Region
Place of Origin
Dimensions73 x 32 x 32 cm (28 3/4 x 12 5/8 x 12 5/8 in.)
Material
DescriptionThe dynamo rests on a wood base. The high oval piece is a magnet, made of several superimposed elements and held together by a brass structure. At the bottom, between the extremities of the magnet's poles, two pieces of soft iron (to eliminate Foucault currents) are fixed and form a ring around the rotor. The purpose of this ring is to concentrate the magnetic field around the rotor. The latter was usually made of several armature coils, connected in series and wound in a special way, called in French "en cage d'écureuil."
The rotor is supported by two brass columns, and can rotate either by hand (using the handle) or by an exterior mechanical force (the grooved wheel, with drawn yellow arrows indicating the direction of rotation). When rotating, the coils are put in contact with a commutator strip on which two brushes run. These two are linked to electrical connectors. The large Jamin magnet magnetizes the soft iron ring, producing a magnetic field that is picked-up by the rotation coils, thus producing a DC signal.
Zénobe Théopile Gramme demonstrated his generator to the Académie des Sciences in Paris in 1871.
The rotor is supported by two brass columns, and can rotate either by hand (using the handle) or by an exterior mechanical force (the grooved wheel, with drawn yellow arrows indicating the direction of rotation). When rotating, the coils are put in contact with a commutator strip on which two brushes run. These two are linked to electrical connectors. The large Jamin magnet magnetizes the soft iron ring, producing a magnetic field that is picked-up by the rotation coils, thus producing a DC signal.
Zénobe Théopile Gramme demonstrated his generator to the Académie des Sciences in Paris in 1871.
Signedon plaque: GRAMME INVR. / BTE. S.G.D.G. / BREGUET FT. / Nº. 97 / AIMANT JAMIN / BTE. S.G.D.G.
French
Date: 1855-1890
Accessories: box of feet for base
4 feet consisting of brass strips with screw holes at either end and iron points
8 screws, somewhat rusted
Object number: DW0329
