Re: gEDA-user: Calculating a linear self excited induction generator

["Samuel A. Falvo II" <sam.falvo@xxxxxxxxx>]

On 6/11/06, Karel Kulhavy <clock@xxxxxxxxxxxxx> wrote:
> I read about self excited induction generator, homopolar generators,
> liquid metal dynamos, interstellar plasma dynamos, linear motors
> and electric meters.

Ummm . . . Interstellar?!

> I got an idea of placing two coils almost touching the aluminium rim and
> wiring them somehow obscurely with capacitors (how people do in wind
> power plants with squirrel cage motors nobly relabeled as "self excited
> induction generators") so they would prime themselves and start
> generating. If it works with cyclic asynchronous motor it should work
> with a linear one too, shouldn't?

In what way is it self-priming?  Given a large enough, flat plate
dynamo, I'm sure one could exploit the Earth's natural magnetic field.
But, a small dynamo the size of which is suitable for a bike would
never have sufficient surface area for electrical generation, no
matter how fast it's made to spin.

Remember that energy is neither created nor destroyed -- if it's
self-generating, it has to draw energy from somewhere.  Traditional
alternators draw this energy from shaft rotation.  Where is the
self-excited generator drawing its energy from?

> 1) Reproduce the electricity meter configuration with externally driven
> 2 coils from relays, one 90deg after the other (the wheel should turn).
> This is how trains and roller coasters with linear motors work so I
> guess it should work.

This is basically a coarse-grained stepper motor as I currently
understand the configuration.

> 2) Drive the wheel manually and see on a scope if the contraption really
> generates more energy than it eats

It will never do so.  If it *looks* like it is, it's because it's
drawing energy from multiple sources.  Remember, with the laws of
thermodynamics, you can't even break even -- you always lose.

--
Samuel A. Falvo II