Re: Generator

"Arne Chr.Jorgensen" wrote:

> The 3phase conversion is interesting, but this is not what I
> meant. I wondered if any have converted a 3phase motor, to a
> 3phase generator.
>
> If it is connected to a line, then an induction motor that is
> forced above the rated rpm, will start acting as a generator. The
> question is, does it need the powerline as a ballast, or is there
> some other way ?

This has been beat pretty much to death on some other newsgroups.
I was of the opinion that the regulation of an induction alternator
would be horrible, with respect to both voltage and frequency.
I was informed by people that have done it, that with the right
selection of capacitors across the lines, you get good voltage and
frequency regulation. This is in contrast to what I'd been taught
in a power EE class, but the capacitors are apparently the secret,
as the circulate substantial imaginary current to keep the rotor
optimally excited.

If you can start the alternator with no load, it will apparently self-excite
within a few seconds, and then the load can be connected. Apparently,
no additional gear is needed, as long as you don't present massive
overloads to the alternator. If massively overloaded, as by a short,
you might have to turn off all loads to allow the excitation to come back
up.

Jon