Dynamo
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A dynamo is an electrical generator that creates direct current using a commutator, and uses self-powering electromagnets for the stator field rather than permanent magnets. Dynamos are self-starting
The Faraday disk was the first electric generator. The horseshoe-shaped magnet (A) created a magnetic field through the disk (D). When the disk was turned, this induced an electric current radially outward from the center toward the rim. The current flowed out through the sliding spring contact m (connected to B') through the external circuit, and back through B to the center of the disk through the axle
Hippolyte Pixii's dynamo. The commutator is located on the shaft below the spinning magnet
Pacinotti dynamo, 1860
The Woolrich Electrical Generator in Thinktank, Birmingham
Alternator
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An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating ma
Dynamo
…and the foundation upon which many other later electric-power conversion devices were based, including the electric motor, the alternating-current alternator, and the rotary converter. Today, the simpler and more reliable alternator dominates large scale power generation, for efficiency, reliability and cost…
Alternators made in 1909 by Ganz Works in the power generating hall of a Russian hydroelectric station (photograph by Prokudin-Gorsky, 1911).
Alternator mounted on an automobile engine with a serpentine belt pulley (belt not present.)