alt.energy.renewable

On Aug 29, 11:57 am, "Steve Young" wrote:
> "Steve Spence" wrote in message
>
> news:46d56655$1_4@ ...
>
> > "MooseFET" wrote in message
> >news: @ ...
> >> On Aug 28, 4:24 am, The Real Andy wrote:
> >> [....]
> >>> The problem it that car alternators do not have magnets.
> >> Any alternator that has been installed and used on a car will "build
> >> up" if you wire it up and give it a spin. There is enough
> >> magnetization left to overcome the rectifier's forward drop.
> > Not without the field coils energized. I saw a circuit once for self
> > energizing the coils. It's still a parasitic load.
>
> Perhaps give the field a split second jolt from a battery, when an rpm sensor
> indicates adequate speed. Use a diode, resistor, capacitor to have the output
> latch it into operation. The generator would engage and drop out
> automatically. Crude functioning circuitry would be cake, with lots of room to
> expand sophistication.

You don't have to do that. When the rotor is going at 1000RPM you
will see a small voltage on the stator even with the rotor not hooked
up. This is enought to get the buildup started.