I am researching AC electric generators, and have seen three different descriptions for the simple design. So I written these three choices up myself, and want to know which is most common:
A. Wire windings as stator, more coils of wires as rotor. Current fed to rotor, become electromagnet and produces magnetic field, rotates (through heat, wind etc) and induces current in stator windings which AC.
B. Permanent magnets as stator, coils of wires as rotor. Rotor rotates through heat, wind etc. and has AC current induced in it. Does not have commutator (ie. same setup as DC electric generator but no commutator).
C. Rotating permanent magnet (rotor), fixed windings as stator. Permanent magnet rotates through heat/other energy and induces current in fixed stators which AC. No commutator (ie. Same as B but rotating permanent magnet with fixed coils, not other way round).
NB. Stator = fixed, rotor = free to move.
I am writing a report on it, and I want to do the most common one of these three. Possibly best would be the one used in power stations to ‘generate’ domestic electricity. If possible, could you please tell me what that type of AC generator is called also after choosing A,B or C?
Thanks in advance. 10 points for best answer.
PS. I realise I have asked this question not long ago, but I didn’t explain it right. Thanks for your help once again.
In a DC electric generator, would B be the most common? Called a dynamo?
18. July 2010 at 1:30 am
“A” is most common. It is the synchronous generator configuration that is used in power stations and most engine-generator sets. It is the basic configurations used in vehicle alternators except that alternators have a rectifier that converts their output to DC.
“B” As far as I know, this is not used as you describe it. It is not an accurate description of an induction generator. An induction generator has no magnets in the stator. It is the same machine as an induction motor. The rotor is a “squirrel cage” made of aluminum (or sometimes copper) bars that are shorted together on the ends with no external connection. The rotor is initially powered externally to induce current to flow in the rotor and produce a magnetic field in the rotor. The rotor field then generates current in the stator to sustain itself and supply power to the source. It works best as a means of supplying additional energy to an already powered electrical grid, but stand-alone systems can be operated with a battery and inverter system designed for the purpose.
“C” People modify vehicle alternators to this configuration by rebuilding the rotor to replace the sliprings and coils with electromagnets. They are used by amateur do-it-yourselfers for home power projects. There are also some small machines commercially manufactured in this configuration for various specialized purposes.
18. July 2010 at 1:30 am
B.
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/motorac.html
http://new.wvic.com/index.php?option=com_content&task=view&id=9&Itemid=46
electrical generator
later – changed definition, sorry.
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18. July 2010 at 1:30 am
Agree with retired EE, except that car alternators also use type A – the rotor has windings, and is only magnetic with current applied .
Only place I’ve seen C (permanent magnet generator) on vehicles, is on motorcycles