Date: Wed, 24 Apr 2002 09:01:45 -0400

Author: Wolfgang Rueckner

Subject: Re: Bicycle Generator 5K40.83


Jerry -- I too have been thinking about this demo off and on. I once
considered the possibility of using an emergency electric generator
and substituting bicycle power for the engine. For example, Harbor
Freight Tools sells a 120 VAC, 5000 W generator for $269 (add your
own engine). But it is meant to operate "up to" 3600 RPM with a 9 HP
engine. Of course the 9 HP would only be necessary when you want to
produce 5 kW of electric power, and we're just asking for 100 W
output. But the RPM issue is a problem, I suppose. It would require
gearing with a ratio of something like 60:1. But then I don't know
what this baby will generate at lower RPMs. If anyone out there has
played with one of these generators, do you have any thoughts on this
idea? Wolfgang

>I am seeking recommendations for a good permanent magnet, low
>voltage DC motor to be used as a generator with an exercise bike.
>The "Generator and Light Bulb" is popularly done with a small hand
>cranked generator, but I need something larger that is capable of
>producing more power. To make a bicycle version I need
>recommendations for a motor that will produce a lot of electric
>current and provide sufficient resistance to your legs when pedaling.
>The DC motor I am now using is something that I happened to scrape
>up and was not selected for this project. It is insufficient. I
>don't have the specs for it but it about the same size as the one
>used in the hand cranked version. When I pedal there is very little
>resistance and a 100 Watt light bulb does not glow brightly. When I
>change loads by changing light bulb Wattage there is little
>improvement. I don't want to use an alternator as a generator
>because the battery and the current for the field coils is confusing
>to students.
>Does any body do a Bicycle generator?
>Can you tell me anything about the motor you use, the
>specifications, maybe the make and the model?
>Do you have any gearing on the motor or the bike?
>Thanks. Jerry