A Gramme machine or Gramme dynamo is kind of electric dynamo named for its Belgian/French inventor, Zénobe Gramme. Gramme demonstrated this apparatus to the Academy of Sciences in Paris in 1871. The Gramme machine used a series of thirty armature coils, placed inside a revolving ring of soft iron. The coils are connected in series, and the junction between each pair is connected to a commutator on which two brushes run. The permanent magnets magnetize the soft iron ring, producing a magnetic field which rotates around through the coils in order as the armature turns. This induces a voltage in two of the coils on opposite sides of the armature, which is picked off by the brushes. Earlier electromagnetic machines passed a magnet near the poles of one or two electromagnets, creating brief spikes or pulses of DC resulting in a transient output of low average power, rather than a constant output of high average power. Dynamo can refer to more than one item. ... Zénobe Gramme, by Mathurin Moreau Zénobe Théophile Gramme (April 4, 1826 - January 20, 1901) was a Belgian electrical engineer. ... Academy of Sciences can refer to a national academy or another learned society dedicated to sciences. ...   City flag City coat of arms Motto: Fluctuat nec mergitur (Latin: Tossed by the waves, she does not sink) Coordinates Time Zone CET (GMT +1) Administration Country France Région ÃŽle-de-France Département Paris (75) Subdivisions 20 arrondissements Mayor Bertrand Delanoë  (PS) (since 2001) City Statistics Land area... Armature is usually the rotating part of an electric motor or dynamo. ... A coil is a series of loops. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... In mathematics, the commutator gives an indication of how poorly a certain binary operation fails to be commutative. ... Iron filings in a magnetic field generated by a bar magnet A magnet is an object that has a magnetic field. ... To meet Wikipedias quality standards, this article may require cleanup. ... now. ... Electromagnetism is the physics of the electromagnetic field: a field, encompassing all of space, composed of the electric field and the magnetic field. ...

With enough coils, the resulting voltage waveform is practically constant, thus producing a near direct current supply. This type of machine needs only electromagnets producing the magnetic field to become a modern generator. Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ... An electromagnet is a type of magnet in which the magnetic field is produced by a flow of electric current. ... Electrical generator Generator (Mathematics) ...

During a demonstration at an inventors' fair in 1873 Gramme accidentally discovered that this device, if supplied with a constant-voltage power supply, will act as an electric motor. The Gramme Machine was the first powerful electric motor useful as more than a toy or laboratory curiousity. His innovation of using a ring armature, was an improvement on earlier dynamos and helped usher in development of large-scale electrical devices. now. ... Rotating magnetic field as a sum of magnetic vectors from 3 phase coils. ... A ring armature is an armature for a dynamo or motor that has the conductors wound on a ring. ... An electrical generator is a device that moves electrical energy from a mechanical energy source using electromagnetic induction. ...

External Links

• Electricity museum: early motors