# Anyone build a wind generator out of car alternator?



## Jim S. (Apr 22, 2004)

I have been thinking I could do this fairly easily, using a 100-amp alternator out of a junkyard. I suppose I'd have to encase the alternator in a shell to protect it against weather, then use an inverter to get 110.

I see decorative 7-foot windmills at Harbor Freight on sale every once in awhile for $25. That could be the base and vane for the project. I would have to hinge the tail so it could be turned sideways when I did not want the windmill operating.

Anybody else ever build one using an alternator? Or is it just too small to supply adequate 110 power to the house grid to make it worthwhile?


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## justmyluk (Apr 28, 2005)

A car alternator (without alterations) will have to turn up to many RPM's before it will generates 12 volts (about 3000 rpms)

Go to ebay and type in "wind generator", look for a PMA (permanant magnetic alternator). They are made using GM Delco alternators but the stator core has been replaced with permanant magnets.

You can get one that starts producing 12 volts as low as 150 RPM's

Unless you are expecting hurricane force winds all the time, I would go with an alternator that has been reworked and more suitable for use as a wind generator. I believe it is well worth a $200 investment.


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## Jim S. (Apr 22, 2004)

Cool jml. Now, will the contraption actually turn out enough juce at 110V to make it worth my while to hook it to my electric system? Or am I just p***ing in the wind?

If it is the latter, I will have to bring a towel.

ANOTHER THOUGHT: If you were to attach the vane to a jackshaft that spun a 12-18" pulley, then belt that pulley to the alternator's 2-inch pulley, you could maybe get it to spin high rpm.


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## PyroDon (Jul 30, 2006)

you can get a PM Ametek motor and get a couple hundred watts out of it but the blades will need to be 4ft or more diameter . depending on the pitch and TSR your not going to get a lot of power unless you build your own PM alternator. take a look at other power.com forums theres a lot of info there.


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## Jim S. (Apr 22, 2004)

thanks


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## FreightTrain (Nov 5, 2005)

i plan on building one with either old DC wheelchair motors or a DC boat trolling motor


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## PyroDon (Jul 30, 2006)

FreightTrain said:


> i plan on building one with either old DC wheelchair motors or a DC boat trolling motor


You can make a small one out of an old box fan . Grind down the induction armiture and epoxie Neo mags to it alternating the polls N/S . you cn used the existing windings but wont get much out of them might light an LED .
But if you rewind it using the correct formula you can get close to 75 watts ( or 6 amps at 12 volts) 
The axial flux alt Im working on should (according to the formulas start producing 12 volts at 180rpm{7mph winds} an produce roughly 300 watts at 400rpm {or 20mh winds} so Im looking at putting an average of 16 amps into my UPS battery bank . With a cost of 25 cents a watt for construction. around 6 kwh a day for a yearly total of 2100 kwhs a year (in a perfect world wher the wind blows constant at 15 mph and doesnt gust to 80 and break my mast)


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## wy_white_wolf (Oct 14, 2004)

Jim S. said:


> Cool jml. Now, will the contraption actually turn out enough juce at 110V to make it worth my while to hook it to my electric system? Or am I just p***ing in the wind?


I hope you understand that the reworked alternaters are DC and not Ac. They also need to be ran with a battery bank to smooth out the power highs and lows from wind gusts or hooked up seperately to the grid.



Jim S. said:


> ANOTHER THOUGHT: If you were to attach the vane to a jackshaft that spun a 12-18" pulley, then belt that pulley to the alternator's 2-inch pulley, you could maybe get it to spin high rpm.


Remember as you increase the drag by gearing with the pulley you also need to increase the blade size to handle the increased load.


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## Jim S. (Apr 22, 2004)

Thanks again! Not entirely sure wind is the way to go here anyway. Solar makes more sense...but is tons more expensive, too. I was just daydreaming on a slow day.


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## dirty (Oct 14, 2005)

what do you use for an electrical connection at the top of the tower? so that the top can still rotate 360 degrees.


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## PyroDon (Jul 30, 2006)

dirty said:


> what do you use for an electrical connection at the top of the tower? so that the top can still rotate 360 degrees.


you have two options one is a wire that you have to unplg and untwist every so often the other is slip rings simular to those found in a car alternator and carbon brushes . I plan to use the slip rings but havent quite got them worked out . This small gen is just the first step if it works as well in the air as it does on the bench tests I'll begain gathering materials for a 1500 wat version . in the 18 ft diameter range ( cost with tower estimated around $8000 so its quite aways down the road ) 
Something I should clarify is that the alternaor Im building is a three phase AC unit that will be rectified to 12 volt DC . the reason for the ac is that the current can be transmitted further at higher voltages with less line loss . It also allows for the use of lighter guage wire . for wind power you will need the turbin,battery bank, charge controler and a voltage dump to prevent over charging


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## ed/IL (May 11, 2002)

http://www.otherpower.com/learningcurve.html go there. They have a message board to ask questions.


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## justmyluk (Apr 28, 2005)

PyroDon said:


> you have two options one is a wire that you have to unplg and untwist every so often the other is slip rings simular to those found in a car alternator and carbon brushes . I plan to use the slip rings but havent quite got them worked out . This small gen is just the first step if it works as well in the air as it does on the bench tests I'll begain gathering materials for a 1500 wat version . in the 18 ft diameter range ( cost with tower estimated around $8000 so its quite aways down the road )
> Something I should clarify is that the alternaor Im building is a three phase AC unit that will be rectified to 12 volt DC . the reason for the ac is that the current can be transmitted further at higher voltages with less line loss . It also allows for the use of lighter guage wire . for wind power you will need the turbin,battery bank, charge controler and a voltage dump to prevent over charging


There is a third option which I use on mine and it works just fine...

I took a light weight spring about 12 inches long (picture an old screen door spring) and attached one end to the back side of my pivot on my genny. I let the spring hang loose and attached it my one inch pipe with a sturdy pipe clamp so it won't turn. The spring will allow the genny to pivot around one full revolution before it starts putting tention on the spring. As the wind dies down, the genny returns to rest position (or close to it) every time. My wire never gets tangled and I know by looking at the spring exactly how many turns are on the wire at any given time (at high winds never more then 2 turns) The system works great and it is a poor mans fix to an age old problem. (the spring cost $3 at lowes) I never need to untangle wires or worry about slip ring failure and the slightest breeze will still turn the genny into the wind in either direction...


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## Runners (Nov 6, 2003)

PyroDon said:


> Something I should clarify is that the alternaor Im building is a three phase AC unit that will be rectified to 12 volt DC . the reason for the ac is that the current can be transmitted further at higher voltages with less line loss . It also allows for the use of lighter guage wire . for wind power you will need the turbin,battery bank, charge controler and a voltage dump to prevent over charging


Unless I misunderstood this.... 
Beware, this will require a 3 phase step up transformer (or 3 transformers). 
Most US transformers are designed around 60hz, so strange things might happen when it's not on frequency. A typical step down transformer, hooked up to do the opposite also yields interesting results.

To find the RIGHT transformer for step up, look for those old inverters, 12vdc to 120vac that weigh a bunch. They've got a real step up transformer, wound with the correct ratio & order (Primary/Secondary) to give max efficency.


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