Date: Tue, 30 Apr 2002 21:03:11 -0700

Author: Martin Simon

Subject: Re: Bicycle Generator 5K40.83


Dear Jerry and others,

I asked a similar set of questions a couple years ago and got some good
advice which I mostly ignored. I had picked up an old exercise bike at
a thrift store and I wanted to power light bulbs in order to talk about
horsepower, kilowatt hours. etc., in units which students could understand.
I had seen something similar at the Toronto science center with a narrative
which went something like, "You come home, turn on a light in the living
room, then you go to the kitchen and turn on another light," etc. By the
time you switch in a few hundred watts, it's pretty hard to petal. I thought
it would also be funny to plug in various kitchen appliances like a blender.

To make a long story short, I never could find a permanent magnet motor
that could be run as a generator to produce 120 V AC. Instead, I also
looked for a permanent magnet DC generator. I wanted something in the
1 HP (746 W) range, because a human can burst up to half
HP briefly. A human can only sustain about 125 Watts though.

They also have a smaller Wattage model which would probably also
be attached.

make it better.

discharged 12 V car battery but that complicates things conceptually.

the pedals continuously under heavy load. The exercise bike has
out the stroke.

with a more efficient smaller inverter. The uneven stroke
and voltage swings may be a problem though.

Despite these limitations it does get used a lot and is liked
by the instructors.

Martin Simon

>I am seeking recommendations for a good permanent magnet, low voltage DC
>motor to be used as a generator with an exercise bike.

>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?