Small Generator / Alternator

Check around with the tractor and farm equipment salvage places. There are loads of old farm machines that had small DC generators on them. Some had generators that where only about 3.5 inches in diameter and 7 inches long at best. They all used external regulators as well.

Some older commercial garden tractors and lawn mowers also had very small generators years ago. I don't recall which brands but they had tiny generators about the size of the starters they used. Roughly 3 x 5 inches as I recall.

Get yourself an old Volkswagen Generator. You can get a 6V or 12V Generator, They will need External regulation, which can be purchased from the same place you buy the generator.

Typical Generator prices range from about $75.00 to $200.00 (new)

Typical Voltage Regulator prices range from $15.00 to $35.00 (new)

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Any small DC motor can be used as a generator, as well as an AC motor for that matter. The older cars had generators but I'm not sure what year the Alternator's came out. I do know that a 55 Chevy had a generator. So you might try a junk yard. Some Fords have alternators with external regulation as well. And as has already been said Tractors are a great source. My Tractor has a generator not an alternator and it's about 5" in diameter and 2" thick.

Good luck with your project.

If I understand, you are making a teaching aid. Teaching generators may be a little old for younger students. If not, you already have some good suggestions for affordable generators. You might want to look at the wheel driven generators that were mounted on bikes for lighting.

If you decide to go to alternator mock up, the first series alternators used by US auto manufacturers all used external voltage regulators. These early regulators were adjustable in the field. With their covers removed, they were good for teaching.

Chrysler designs of this type were used from 1961 to 69.

GM designs of this type were used from 1962 to 72. Some models started internal regulators in 1969, so watch your wire connectors to tell.

Ford designs of this type were used from 1962 to about 1978. Again watch for electronic versions of the regulator, as they interchange with the mechanical units. The mechanical units are about 2 " thick, and have small screws holding a cover on.

A little bit harder to find, but a better teaching tool was the Motorola, and Lease Neville alternators. They had external A/C taps on them. This would allow showing how electricity is concerted from A/C to D/C. These might be found at a business that rebuilds alternators. They are now so old, that selling them has become impossible. (think donation at this point) the early versions of these also had external mechanical voltage regulators. You might contact either of these companies, they might be willing to send teaching materials for demonstrations.

As far as a motor to run the alternator, why not find a starter motor with a starter drive mounted outboard of the housing. Remove the drive assembly and attach a pulley to the exposed shaft. You could use a small lawn tractor battery to power the motor, and collect the power from the alternator. Or you could just use jumpers from an auto near. Good luck.