PM DC Motor as also a few separately excited ones can generate voltage.
My son is doing it by breaking his two toys and using one motor to drive other as generator (based on my idea- no not the car breaking )
That is to make generate some concept in generators as well as the efficiencies (the light of the bulb at the generator vs directly connected to cells).
A permanent magnet motor will also function as a generator.The output will increase with speed.
There are many PM DC motors to choose from,so select a motor with an input voltage/current slightly greater than the desired output.
Many 24 volt PM DC motors are used on conveyor systems.
How do you intend to drive this generator? You could use a fixed speed ac motor, and use an adjustable regulator, but why go through all that trouble, when you could simply build or buy a regulated DC power supply?
If you are considering using manpower to turn it, like with a bicycle type drive, you will only be able to sustain a fraction of a horsepower, but perhaps you could run a small TV or satellite system.
Good luck with your project.
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