electromagnetic generator
Date1920-1950
Inventory Number0151a,b
ClassificationElectromagnetic Generator
Subject
Maker
Spindler & Hoyer
1898 - 1996
User
Department of Physics, Harvard University
founded 1884
Cultural Region
Place of Origin
Dimensions13.2 × 58.5 × 13.7 cm (5 3/16 × 23 1/16 × 5 3/8 in.)
Material
Bibliography
DescriptionThis generator consists of a horse-shoe permanent magnet fixed on wedged piece of wood, itself sliding in a wooden base. A coil mounted on a horizontal shaft is rotated in the constant magnetic field of the horse-shoe magnet. Both ends of the coil are linked to a commutator, which is touched by two collector springs. The wheel turning the shaft has a handle (that falls off easily) so it can be rotated by hand. The wheel though is grooved, to act as a pulley, so it can also be mechanically turned by a motor.
Signedon base: SPINDLER & HOYER / GÖTTINGEN
Curatorial RemarksWas first incorrectly catalogued as 1997-1-0259a, so slide in the CHSI library will show it with that number.
FunctionThis device was used to generate DC current by a fluctuating magnetic field. In opposition to the AC generator the two collecting rings are replaced by a commutator. After each half-period of rotation the connection between coil-ends and pole-terminals are interchanged and the voltage oscillates from zero to maximum while the sign does not change.
ProvenanceFrom the Department of Physics, Harvard University.
Philip Harris & Company, Ltd.
Date: circa 1950
Object number: 1997-1-0639
L. E. Knott Apparatus Company
Date: 1910-1930
Accessories: bell jar
Object number: 0189a,b