Which Alt are PMA's?

[Oddjobsetc]

I was wondering if anyone is using of the shelf PMA's. I know that certain alternators specifically old cars and ag are already PMA's and typically have a lower rpm. I was just wondering if anyone has used these with little or no modifications? And if they were modified what was done. Anyway I'm just starting here, I don't have a problem buying one specifically for wind turbines, I just don't want to pay $300 for something I can buy for $50 because I don't know any better.

[smidy]

well i don´t know what cars that had pma´s, I have friends that restuarating old cars one i specialitated on ford model A & T and what i seen they have no pma, other friends that intressted in younger cars 50-70´s and they don´t have pma´s, i think you get it wrong, you are talking about generators and alternators, generators don´t need retifiers, but they are not pma, old cars had generators up to about 70´s

[kurt]

if you want a 4' mill that will make a max of 10 amps at 12v look for an  Ametek on ebay here is a website that will help you pick the good ones from the bad ones http://www.tlgwindpower.com/ametek.htm   if you want a bigger mill like 8' or so look for a 1.5-2 hp permenent magnet dc motor 90 volt 1750 rpm that will be good for 12v if you want to go 24v look for one that is 180 volt 1750 rpm. try to get as large a shaft size as you can get. wdyasq posted a link to a motor frame chart in a comment to somebody a wile back if you could search that up that would be handy to have...... all you need to make any of these mentioned motors into gennies is blades and tail a blocking diod batteries and a tower to stick it on.

[Flux]

Ford A  & T did have PMA for ignition, the things were massive and the output negligible, they are in no way suitable for wind power.

Later cars had wound field dynamos and later alternators. None were PMA because of the difficulty of regulating. A few motorcycles used PMA but again they are totally unsuitable for wind power.

It is possible to convert car alternators to permanent magnet, but it is a lot of effort to produce an almost useless end product, ok for a bit of fun if you have some time and magnets to spare, but hardly worth the effort of buying magnets, you will almost certainly need to rewind or reconnect to get any power at wind generator speeds.

At best you will end up with an inferior copy of the AirX. My advice don't waste your money.

Flux

[DanB]

The 'T' had a PMA for ignition which was interesting and not terribly far removed from some of the single rotor machines people around here are building (and I have built in the past) =- although they did some silly things I think (like having solid steel cores over the tops of the holes in the coils) and it was large - attached to the flywheel and using weak 'steel' magnets.  It's not useful for much actually.

The 'A' did not - it had a fairly normal 'generator' or 'dyanamo'.  The early model A Ford had a 3 brush alternator which could be setup to work at very low rpm and was suitable for small wind turbines although nothing compared to some of the perm. magnet stuff that's out there now.

And yes - to back up what Flux is saying - other than the model T ford I've never seen a PMA used in any car although I wouldn't be surprised if a couple other companies way back then were doing similar things.

[Oddjobsetc]

Thanks for all the responses. Perhaps if I give a little more info then I could get more help. So far it sounds like the alt is not the way to go. I plan on building a 8 or 10 ft dia turbine. I was looking at premade blades either aluminum or composite. I prefer aluminum. Would the best route be a high volt dc motor like suggested or to build my own. I have seen some guy on ebay offering a 800 w kit including blades mount and converted alt for $350. What about these converted alts? are they still a waste of time and money? Is it possible to build a homemade gen of good quality without a complete machine shop at home? Thank you for all the help

[wooferhound]

If you want to build and fly a wind generator there are several things you will need.

• A Generator
  
• Blades
  
• Tower
  
• Electrical System
  
  

Sure you can buy all of these things but whats the fun in that

And if you make the stuff you will quickly see that you will need lots of tools

I made this small 200 watt genny with just a Skill Saw, Jig Saw and a drill for power tools.

[Flux]

Thanks to Dan for correcting me about the Ford model A. It was the Fordson tractor that also had the flywheel magneto.

For 8 to 10ft blades then you are well out of the range of any converted vehicle alternator irrespective of what some crook is prepared to charge you for it.

You have plenty of options, you can buy an expensive low speed PMA designed for wind power, you can convert an induction motor by adding magnets  or you can start from scratch and build an axial PMA. If you have limited facilities then you can buy all the bits to build an axial including discs, magnets and wire. You can find a vehicle hub or you can buy a commercial trailer hub. If you have no real facilities then a motor conversion may beyond your means unless you are prepared to pay for machining.

I would be reluctant to use aluminium blades at that size without seriously studying the credentials of the supplier but that is your choice.

Read this site especially the Otherpower pages where there are plenty of practical designs. Forget stupid web sites that promise you the earth for a little relief of your cash. They are ok for tiny 3 or 4 ft machines where you don't expect much and you will not get much. For big machines in the 10ft range you might as well pay what it costs to make something that works. You will see little benefit from something totally unsuitable and probably fast and dangerous.

Flux