Dynamo
Cread by JohnAnkerBow · recorded January 7, 2020 · 0:15:00 · 10.3 MB
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 by using residual magnetic field left in the iron cores of the electromagnets (i.e. field coils). If a dynamo were never run before, it was usual to use a separate battery to excite or flash the field of the electromagnets to enable self-starting. Dynamos were the first practical electrical generators capable of delivering power for industry, 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 reasons. A dynamo has the disadvantages of a mechanical commutator. Also, converting alternating to direct current using rectifiers (such as vacuum tubes or more recently via solid state technology) is effective and usually economical.
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