Anyone use 1/2 inch Neo 42 Grade Wedge Magnets?

[Bischofk]

Ive been doing alot of reading about wind generators over the past month and have come to some conclusions (which I hope are accurate, please correct me if im not).  To build an efficient alternator you need to have the proper awg wire, proper number of turns on each coil, and the strongest magnets you can find with the right dimensions.  It seems that the wedge magnets provide the most surface area, and are available in 1/4" and 1/2" thicknesses.  Ideally you would go with the 1/2" thick magnets to increase flux in the airgap.  

With that said, I have yet to come across anyone who has designed a stator using 12 x 1/2" thick grade 42 neo wedge magnets on each rotor.  Based on Ed Lenz's site, he uses between 40 and 44 turns for the 1/4" thick magnets (lower grade as well).  So it seems to me that I could possibly reduce the number of turns on my coil and perhaps even increase the awg some to allow for a more efficient coil design usings these better magnets.  

So could anyone provide some guidance on how I should design a 12 pole, 9 coil stator using the above mentioned magnets.  

NOTE: Goal here is not to build the cheapest alternator, but the very best, why?  Because thats how I roll .  To me this project is as much about the science and fun of building it as it is to just generate some extra power. I want to build the most efficent generator I can do feasibly.

Thx in advance for any advice you folks can provide!

Peace

-Kurt

[Flux]

I suspect that the reason you don't see many wedge magnets is that they are rather expensive compared to the standard rectangular blocks. Much of the price depends on demand and certain shapes are relatively cheap.

The wedges will work fine and if you use the thick ones they should be great for a single layer winding. You will need to space them so that the gap between them is something like the mean magnet width or more to make best use of them and you will need a stator something like 5/8" thick running is a gap of something like 3/4".

If you do all this, do a test coil and get your turns right then use the thickest wire you can get in you should have a very good result.

Need more details to give much other guidance including the actual size ( plan area ) of the magnets and proposed prop size.

Flux

[Bischofk]

Ok, so more information

Here are the magnets => "http://www.magnet4less.com/product_info.php?cPath=1_15&products_id=457&osCsid=67a97b954e5ad7925bed9055a793d7e1">http://www.magnet4less.com/product_info.php?cPath=1_15&products_id=457&osCsid=67a97b954e5ad7
925bed9055a793d7e1


If I understood our mean width spacing, that would be the mean of 1.57 and .78, which equals 1.175".  Based on that info, doing some calculations, I should use a rotor diameter of 10.5".  I assume reducing to 10" would be ok, given 10" rotors are pretty easy to come by?


Also the goal is to stay under 10' Blade diameter.  This is my first project so I dont want to go to big, nor do I think I can accomidate a large unit at this point.

[Flux]

I couldn't get your link to work but from your dimensions then they should be spaced at least 1.175". I would have chosen to go bigger and probably used 12" discs but you say you want to keep it under 10ft.

You should manage this with 10" discs but I am not sure it would be as cheap as using 2 x 1 x 1/2 magnets on 12" discs.

You should have a machine capable of dealing with a 10ft prop with the 10" discs but with bigger discs you could have lower resistance and put more loss in the line rather than the stator.

Depending on your prop choice you should cut in between 140 and 180 rpm for 10ft, a little faster if you choose something under 10ft.

As always by doing your own thing you have to make lots of decisions and choices but it will be fine if you get it right. For a first machine I would have suggested going for something already proven rather than go your own way but that's life.

Flux

[Bischofk]

Actually im not really trying to do something all that new honestly.  Ed Lenz's alternator uses the 1/4" thick wedges but are the same dimensions.  The only modification I am making would be to the thickness of the magnets (which I assume is a good choice).  The only issue is there doesnt seem to be an exact recipe for that out there.  So im not really trying to go against the grain here, Im just trying to use my resources (you guys) to build the best alternator I can.  I dont have the luxury of building several wind generators because my location simply wont allow for it.  So if I build one, I want it to maximize power output for the small amount of room I have to work with.

[electronbaby]

http://www.fieldlines.com/story/2004/3/22/102529/026

Heres one I did in 2004 with similar magnets.

[cyplesma]

Mind you this is probably the most UNrecommended method of making a windmill. But hey I like challenges. 8 )

Well, here is a picture of what I have in (slow) progress. Not a great shot of the magnets themselves, but they are the smaller ones.

http://www.otherpower.com/images/scimages/4112/rotormountedovercoil.jpg

That is a 16 inch bicycle wheel. I respoked it so the spokes are even with the rim on one side and stick out farther then normal on the underside. I used 1.5 inch by 1.5 inch slotted angle wrapped around and bolted to the rim. The coils shown in the picture are 43 turns of 14 awg. I have replaced them with coils that are 83 turns of 14 awg. wire.

I can get a standard 9006 car headlight to glow at 3 volts, at 4  - 4.5 volts it is pretty bright, having trouble getting an amp meter to measure the amps, it is very hard to turn though.

I can turn it fast enough with my finger to light up a standard car instrument panel light.

Turning it with my finger I can get 19 - 20 volts without straining (200 - 250 rpms), with straining and I get it to about 22 volts for about 3 - 6 seconds before my finger whips out of the spokes (300-340 +rpms).

[cyplesma]

I should have said the smaller WEDGE magnets.

[cyplesma]

also 16 magnets 12 coils

very pretty sine wave too.

[Bischofk]

Are those magnets larger than the ones Im looking at?  I was planning to use a 10" diameter rotor, and yours is 14 and still doesnt appear to have a ton of room between magnets.  According to my calculations with 10" I will just JUST under the recommended 1.175" gap between magnets.  It looks to me you have a gap as wide as a penny which certainly isnt more than 1".  Can you elaborate?

Oh and do you have any links to DanB's generator?  Perhaps some info on what type of power he was getting?  How many coils yada yada?

[bob golding]

hi ,

i have built a turbine using those magnets. i am on my third redesign. the first one was  using 16 single magnets on each 10 inch disc with i think 45 turns of single 15awg wire with a 8 foot blade. this worked fine for about a year until the bearing gave way and took the stator with it. i was getting around 250 watts out of that setup. i made another stator using 2 in hand  17awg 45 turns at 24 volts. this worked fine with a smaller  6 foot prop. i then added another 32 magnets and this was a great improvement. this worked fine until i tried running it at 12 volts. i was getting  25 amps at furling until the last big storm  with 80 mph winds which caused the stator to burn out again. having learnt my lesson the next version will have more wire. to achieve this i am going to 14 inch rotors and 9 coils 12 magnets. i have a mixture of 3/16 and 1/4 inch magnets so i  am gluing them together to get 1/2 inch. still need to wind a test coil to calculate turns. i will let the group know when i have something to report. so to answer your question ,yes you can use the wedges but you are making work for yourself getting to right. nothing wrong with that but, if you want to get up and running quickly i would stick to the rectangular magnets and the tested designs.  you will be more or less on your own otherwise.

cheers

bob golding