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agrifabs
New Member
United Kingdom
76 Posts |
 Posted - 12/08/2007 : 21:26:40
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good evening everyone,
i have just been looking on ebay foe pm motors and i noticed that 'beewind wind generators' are offering a pm alternator for £160, they state that -
These PMAs (Permanent magnet alternators) have been made from remanufactured GM alternators. They each have a very strong neodymium magnet, specially wound stator, new bearings. These are the PMA's that we use in our Beewind wind generator systems and have such wonderful results from.
just wondering if anyone has one of these. how good they are and is it possible for a mechanicaly minded person to convert a normal alternator into one of these? if so - whats required?
chris
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ll81
Junior Member
124 Posts |
Posted - 13/08/2007 : 16:30:09
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You will need special heating and pressing equipment to remove the iron legs that conduct the flux from the field winding. Then you will need Neodymium magnets that have the same amount of poles as the original field. After that you will need to rewind the stator phases to give low RPM output. There is another bloke on Ebay.co.uk selling PMAs (just type PMA) made from modified alternators. Looking at the power curve the Beewind alternator works well. I brought a set of blades from them and they are good.
woo-hoo |
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gotwind
Forum Admin
United Kingdom
949 Posts |
Posted - 14/08/2007 : 21:49:55
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They do look tempting, please remember: you would have to seriously waterproof these converted alternators for outdoor environments, Particularly the U.K 
Futurenergy's 3 phase alternator is another option for a similar cost.
http://www.futurenergy.co.uk/products.html
The Futures Green - Getwind of it. |
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ll81
Junior Member
124 Posts |
Posted - 14/08/2007 : 22:06:01
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I don't think you do. The diodes are hermatically sealed and are the only components in there. The copper wire is covered in enamel and the water won't hurt the magnets. A squirt of oil on the bearings every 6 months should be all it needs.
woo-hoo |
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Victor
Junior Member
United Kingdom
413 Posts |
Posted - 15/08/2007 : 00:51:21
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ok.
Reading this I would suggest that this sounds like someone wanting to make a serious Wind Turbine.
I think the motor on bens link would be perfect if used with something like Hugh Piggots blades?
Decent generator off the shelf with a decent set of 30 degree angle wooden blades?
What does the forum think?
I can only see this as the nearest youll get to an off the shelf generator where you can spend more time on making a decent set of blades that will last.Also considering the time you have to find magnets and the additional post costs of selecting materials it would make sense to buy in certain parts.... I think one of the biggest parts of the turbine that are expensive are the blades themselves and in most cases vastly overpriced for what you get.
Maybe this is the best way forward.
Purchase
1 - Permanent Magnet Generator
2 - Make a Decent set of Turbine blades from wood.
Now that we have these two factors sorted the only thing I can think of that could make a problem on a finihed generator is the tangling of the electricity wire.
I think thats one of the things we would all need to try and work on.....
A 360 degree swivel with no wires ever getting tangled.
I`m sure this is the only way to make a decent output turbine than going to the shops and getting ripped off 4 times the price!!! |
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Del
Junior Member
United Kingdom
369 Posts |
Posted - 17/08/2007 : 09:42:16
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Just adding my two-penneth on the waterproofing issue. I spent a week at the Northern Green Gathering recently and got up close and personal with quite a few turbines (Rutlands, Air X, Aerogen, my own 5 bladed Ametek and most interestingly a Hornet). The Hornet (they are occasionally sold on ebay) uses a modified GM alternator and a six bladed Air X type blade set-up. The guy who had it lives permanantly in a 1960 Beford horse box lorry which is very nicely converted. His Hornet runs on a mast on top of the lorry (with a PV array) 24 hours a day / seven days a week and is absolutely fine in the rain.
I agree with Victor totally though. I think we're evolving beyond 100 watts and PM generators are available for sensible money. I would love to see more people carving their own wooden blades and working out a cheap split ring solution - maybe a modified car horn set up - just not sure on the power handling side though.
Cheers
Del. |
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BushWhacker
Junior Member
Canada
329 Posts |
Posted - 20/08/2007 : 04:29:18
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Stumbled on this quite by chance but perhaps it will help...
http://www.windstuffnow.com/main/gm_alt_mod.htm
Cheers!
BW
Think about how stupid the average person is; now realize half of them are dumber than that.
- George Carlin |
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BushWhacker
Junior Member
Canada
329 Posts |
Posted - 20/08/2007 : 04:37:01
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Victor wrote
"Now that we have these two factors sorted the only thing I can think of that could make a problem on a finihed generator is the tangling of the electricity wire.
I think thats one of the things we would all need to try and work on.....
A 360 degree swivel with no wires ever getting tangled."
I have read some post saying that if you use about 30 feet of (pipe if I recall)mast and hang some pretty heavy gage wire down the center, when the wind stops the HAWT will self unwind. If I recall correctly these folks were talking about either 2 or 4 gage cable hanging down the center of a 30 foot mast with an exit hole at or near the bottom.
Hope this helps,
BW
Think about how stupid the average person is; now realize half of them are dumber than that.
- George Carlin |
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shawn
New Member
United Kingdom
61 Posts |
Posted - 05/07/2008 : 00:10:17
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This looks very simple if its true.
One magnet and your done 
http://www.fossilfreedom.com/alternator-conversion.html
EDIT:Been studying this and tell me if I'm wrong but its not the magnet seen through the gaps that is creating the fields but the claws are charged N and S because the flat faces of the magnet are charged N and S. SO you want the biggest magnet you can find in there but its not crucial its a dead tight fit on its diameter.
Have I grasped that?
So if you have a press and alternator and £15 for a magnet this is a cheap easy way to go.
These types of alternators don't need furling either do they because they are happy to go to 2000 rpm? |
Edited by - shawn on 05/07/2008 19:55:16 |
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optixelectrics
New Member
United Kingdom
72 Posts |
Posted - 05/07/2008 : 22:05:12
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Re the furturenergy option. I have the 48V 1KW version of this. the rear bearing gets water in it, then if left, will rust and seize up. Luckily the bearings are standard off the shelf items. When I rebuilt mine, I sealed it properly, and it hasn't been a problem since.
The 1100W units for sale on ebay are old stock, but still better built than the FE unit. Renewable energy as I understand it aren't putting the 1100W in their turbines anymore, only supplying their turbines with the RC2200W version (which is bulletproof, but very expensive at £400 for the PMA, or £1950 for the whole turbine).
Myk |
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gotwind
Forum Admin
United Kingdom
949 Posts |
Posted - 05/07/2008 : 22:21:40
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Interesting Myk,
Water (moisture) ingress with any outdoor turbine is difficult to suppress as I understand - internal/external pressure balancing.
All wind turbines suffer the same fate I suspect.
Just makes the task of generating our own energy that little more difficult - and interesting to overcome..
Ben. |
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Hefhoover
New Member
United Kingdom
69 Posts |
Posted - 06/07/2008 : 02:06:49
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| On many vehicles the alternator is mounted close to the front and takes all kinds of crap flying in through the radiator, you just need to have a look at the state of some of them. |
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BushWhacker
Junior Member
Canada
329 Posts |
Posted - 06/07/2008 : 02:26:48
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Shawn wrote "These types of alternators don't need furling either do they because they are happy to go to 2000 rpm?"
Not meaning to burst your balloon but the problem is the blades at that point. Will they fail at very high RPM? Pending the location of your turbine and the nearest normally habitated space near it, you may have a potentially lethal combination in high winds. Even if no one is around during the blade destruction it can cause significant damage to the rest of your setup due to balance problems causing vibration and worse.
I have read several accounts of well made blades failing at high speeds due to a lack of, or failure of furling devices.
Just something to think about,
BW
Everything should be made as simple as possible, but not one bit simpler. - Albert Einstein |
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fungus
Moderator
299 Posts |
Posted - 06/07/2008 : 10:45:52
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| shawn: yes; a single large donut magnet in the middle does work for replacing the power needed for the field coil, however this still doesn't take away the requirement for high speed to the generator. One thing many people havent mentioned yet is that the bearings on car alternators are very small, they're only built to take the stress of the pulley/belt and I'd be wary of mounting a full bladeset straight onto them .. therefore it might be better to gear up using a good pulley anyway .. just a thought. Otherwise a rewind of the stator coils would be needed to lower the speed requirements. |
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shawn
New Member
United Kingdom
61 Posts |
Posted - 06/07/2008 : 11:58:13
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Thanks Fungus!
Got a brand new alternator on its way and I'm going to graft that starter motor gearbox onto it giving a 5.5:1 ratio. Then I'm going to construct that self regulating silent VAWT and stick it on my roof
Well that's the plan for today but it keeps changing.
A central drive shaft down through its bottom bearing.
Alternator will sit underneath out of the weather.
So there will be no load on the bearings.
Bit at a time, got to get the alternator working first |
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shawn
New Member
United Kingdom
61 Posts |
Posted - 06/07/2008 : 14:26:19
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Been looking at the wind blue rotor and I'm guessing its a ceramic magnet in there as opposed to a neo or else why paint it
Also going off the price its too cheap to have a neo of that size.
Anyone know for certain? |
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Topic |
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gm alternator?
