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Re: 3 phase car alternators



Original poster: Jeff Larson <jeff@xxxxxxxxxxxxx>

When we did the alternator trick 15 or so years ago, all the regulator electronics where removed. I think on the one we had is was external? I don't remember. But you are right, we went straight to the brushes with the 12 or 24 volt DC. And it seemed that the 8 HP was not enough to
keep the whole thing going at the speed and load that we where running it at.
Please remember that the voltage may get alot higher than you think. We were pleasantly surprised the first time we did it.

Jeff Larson

Tesla list wrote:
Original poster: Tim S <stm800@xxxxxxxxxxx>

when you modulated the field winding did you remove the guts from the thing that holds the slip ring brush contacts to the field winding?

there are active electronics resistor/shunts/and a voltage regulator in there.
 i removed the guts and wired the brushes straight out the side hole.

i think i might have some time this weekend to try it out a bit.

can someone give me some ideas on how i should plot some data?

i have mine hooked up direct drive to an old wood router.
the router will run directly from a dc voltage and the last time i remember 12 vdc on the router gave it 20,000 rpm with no load attached. i will dust off my hand held tach for router rpm and scope with frequency counter for the output of the alternator.

i will at least start the idea back up for i allready have the stuff collecting dust and taking up room..if it don't work out to the trsh it goes..

tim



Tesla list <tesla@xxxxxxxxxx> wrote:
Original poster: "S&JY"

I tried your idea below many years ago. I modulated the field winding and
left the rest of the alternator as-is. The idea was to modulate the field
winding at 60 Hz to cause the D.C. output to be modulated also at 60 Hz.
Sort of like a magnetic amplifier. Unfortunately, at least for the
alternator I tried it with, the "frequency response" rolled off drastically
at only about 10 Hz, and at 60 Hz there was no useful AC output. Very
disappointing. But maybe you have a different style alternator that can
function well with a 60 HZ field excitation. Please let us know how it
works for you.

--Steve Y.

----- Original Message -----
From: "Tesla list"
To:
Sent: Wednesday, October 18, 2006 6:38 PM
Subject: Re: 3 phase car alternators


> Original poster: Tim S
>
> i might just do this experiment as i have an acdelco 108 amp(pre 1980 i
think)
> with internal diodes allready removed and i also removed the
> internal module that regulates the field winding.
> so i have a bare bones setup.
>
> once i thought since the field winding is a north south static
> polarity why not use a mosfet bridge and modulate the field winding
> with a frequency say 60 hz and see the result of the 3 phase
> windings.i am sure due to the iron claw core that is inside covering
> the field winding there will be some frequency that the field coil
> will saturate at but i really don't know the answer.that is why i was
> experimenting in the first place.
>
> i started this idea 8 months ago and due to other things always
> popping up i never got to finish this idea.
> tim
>
>
> Tesla list wrote:
> Original poster: Jeff Larson
>
> About 15 years ago when I started playing with Tesla coils my friend
> and I were looking for sources of high voltage since we had burned
> out the transformers that we had. We had taken apart a alternator
> and removed the diodes and extended the stator windings out of the
> case. I think we just fed them through holes in the side. This was
> C clamped to the welding table. We then put a 18 inch pulley on a 8
> Hp Briggs and Stratton gas engine that had a horizontal shaft. The
> engine was also mounted to the welding table so that a belt was
> placed on the large pulley and the tiny pulley of the
> alternator. The speed ratio between the engine and the alternator
> was huge. Like maybe 1 to 9. Any way,
> the engine was started and run up to speed. The alternator was
> singing at a high speed. Then 12 volts was applied to the field
> winding, or was it 24, I don't remember. What I do vividly
> remember was the hot arcs that jump between the stator wires sticking
> out in the air. It was like a Jacobs ladder. Man did that put a
> load on the engine. It would bog the engine way down until we
> removed the voltage on the field winding.
> I don't know how much voltage was on stator, but the wires must have
> been about 1/4 to 1/2 inch apart. So maybe 10kv. Imagine that! We
> didn't use it for anything, but it was fun.
> I think someone out there needs to revisit this experiment. Who has
> the stuff , and the time? A challenge. We will want to see video.
> Jeff Larson
>
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