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Forum Index : Windmills : Wind power in Africa
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Orphanjt Newbie  Joined: 04/08/2010 Location: KenyaPosts: 2 |
Hello Everyone! This is my first post, though I have been looking at the website for months now. A friend and I are very interested in Windmill Technology in Africa. We built our first windmill using a PM motor about 6 months ago. From there we started using 12V car alternators, rewinding them, and then using them to produce the power. Alternators are more accessible and affordable than PM motors. All we do is find an alternator with an internal regulator and rewind with about 23-25 gauge wire, depending on the wind in the area. And from there it is easy. I am now working in Ethiopia and then traveling back to Kenya. While here, I met a man who suggested using a 24V truck alternator. He said we could just change the internal regulator to 12V and then possibly rewind with smaller wire, or not rewind at all. That, he said, would give us more power. I have read a lot about using alternators as wind turbines and there is a lot of differing opinion. If I was back in the US I would use a PM Motor, but here alternators are easier to find, affordable, and rewinding can easily be done. Therefore, with the knowledge of how to build a windmill the power can literally be in the hands of whoever wants it. Mainly, we are working with rural groups, rural people, and NGOs. They mostly want it for charging batteries, a few lights, a radio, and charging the mobile phones. That is the background. I am looking for feedback on how to make a 24V alternator suitable for windmill use. Would you have to rewind it? Would it be as simple as just changing the regulator to a 12V regulator? Has anyone tried before? I have read in a past forum about converting the rotor to PM, but that is not possible. Any suggestions about using a 12V car alternator for windmill use? Thank you in advance for any help. Josh |
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Josh I have used one years ago, it was a 100 amp delco of a diesel truck engine I didnt use a regulator as it was charging a large battery bank, just wired off the rectifier and used a high voltage cut of relay that shorted the alternator to a bank of globes, it put out 20 amps in strong wind with a 68 inch 3 blade propeller, the disadvantage was it needed a lot of revs to work around 1500 rpm I believe, rewinding would lower the cut in point, but it still needed power to the rotor, 3 to 4 amps from memory. I believe it would be better if fitted with neo magnets or any strong block magnets for better efficiency. It would be better to belt drive and use a 10 ft 3 blade for better power output, 4 or 5 to one step up. I had better results using a conventional brush generator, as they worked better at lower speed and only needed a reostat to the field to control the output, or the conventional voltage regulator. Bit hard to get now but should be still available in the scrap yards. All the best Bob Foolin Around |
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niall1 Senior Member  Joined: 20/11/2008 Location: IrelandPosts: 331 |
i remember trying to convert one to neos ..i cut slots in the claws and epoxied in the mags , turned out the magnet size was a perfect match to the laminate slots.. it cogged so bad you could almost here it click as you turned the shaft... 
the 24v truck alt seems a better proposition at least youd have a lot more room to work with and possibly more poles as well..if you had a bench press i think its possible to remove the claws and maybe put a couple of ferrite donut mags in there instead of the coil....then replace the claws .....never tried it though... 
http://dragonflypower.com/DragonBlerb.htm...this is the nearest i seen to a car alt mill.....might be some ideas in there ...prop size...gearing ratios the method of field coil activation is pretty interesting niall |
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GreenD88 Senior Member Joined: 19/05/2009 Location: United StatesPosts: 104 |
http://www.windbluepower.com/Permanent_Magnet_Alternator_Rot or_Fits_Delco_10SI_p/pma-rot.htm Here's a Permanent Magnet Rotor for Delco alternator. Basically they replaced the Rotor Coil with a donut magnet. Licensed Master Plumber / EPA 608 Universal License / 410a Safety Certified / Medical Gas Brazer/Installer |
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| niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331 |
its interesting that they use a stainless shaft....if it was regular mild steel the flux (or grap) in the claws would be weaker ...maybe a mild steel shaft provides a short circuit or alternate path for the flux ? .....i think i read something about this effect before from what other people have tried niall |
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