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Forum Index : Windmills : Neo Conversion
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| brucedownunder2 Guru  Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Well, I've finished the Neo Hub conversion. Not so good news,but. It's very powerful,maybe far too powerful. I get a little cogging 1/4 way wound in ,and just tirning it ever so slowly ,I see around 40 v dc out of the 7 phases. Screwing it in 1/2 sees a lot of cogging ,and 60-70 vdc. This is just turning it very slow-say 30 rpm. screwing it in fully = very hard to turn So, hopefully the F&P hub will be here today or Monday, then I can compare it to mine. I've triple checked the magnets nn ss nn ss nn ss and they are correct ,but hugely powerful-you'd never get a hub off if that special nylon backing nut broke off !!. So ,thats disappointing ,but never mind ,we'll wait for the F&P hub bruce Bushboy |
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Saaremaa Newbie  Joined: 10/12/2005 Location: AustraliaPosts: 13 |
Seems too obvious to be a solution - but can't you just use half the magnets ? I'm assuming you have banks of 2 smaller magnets together at each pole? It would be cheaper but still allow you to use the 7 phase artrangement. |
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makourain Senior Member  Joined: 19/04/2006 Location: Posts: 111 |
half the magnets half the power |
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| Saaremaa Newbie Joined: 10/12/2005 Location: AustraliaPosts: 13 |
"half the magnets half the power " Yes, correct - but it may be that a rotor with half the neo magnets will have more power than the standard ceramic magnet rotor - and no cogging |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Well, I'm at a lost to know what's wrong -remember last week I put the magnets in nsnsnsnsnsns and got NO COGGING but very little o/p. Well I've removed all the magnets ,cleaned every one of the 192 beasts and installed them nnssnnssnnssnnss ,but now get heaps of volts (no load) but also I now get BIG time COGGING. Bye the way I've checked the wiring on both the 7/2 and 7/6 pole re-configured stators-all seems to be OK . So, F&P must have a more complicated new magnet system than us just replacing with 48 Neo's and doing the re-wire part?? As far as my placement of 2 end to end and then a second on-top row ,making 4 small magnets per "tile" and per pole , I'm wondering if this arrangement is far too strong a force and creating the cogging effect?? Maybe I can remove the top row , creating more "Gap" and therefore reducing the cogging ,OR, I wonder if this top row of magnets are interfering with the polarity and causing the cogging???. My head hurts big time today---- Thanks for your help Bruce Bushboy |
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| clarence Regular Member  Joined: 27/10/2006 Location: Posts: 63 |
thats a shame about the cogging Bruce, I have been watching your progress with interest and I have some neo's coming early next week.I was going to try this 7 phase experiment myself, but I might hang off a bit now. thanks for doing the hard work. I wonder if it could be due to the precise width of your neo's? I was thinking if slightly larger width neo's were used, the gaps between magnets would decrease and perhaps help with cogging? what this would do to performance I have no idea. what is the size of the space between your neo's btw? cheers,clarence. |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I would wait untill you get the factory hub, and then compare the magnet arrangement to yours. I have this feeling something is not right. You need to put on the factory hub and see if the cogging is gone and it makes power, then you know the stator is right. I know magnet placement is very critical on a F&P, out by a fraction of a degree and the whole thing goes bad. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Yes,Clarence, you could be "on the money" with suggestion .. The gap is fairly wide @ 9mm . So ,if I were to make another I would need to buy wider Neo,s ( approx $120 ) Dosen't make ecomical sense when you can buy a F&P factory one for $60. I only did this because I had the magnets allready. Bruce Bushboy |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Hi Glenn, Monday or Tuesday the new hub arrives--Bloody F&P won't sell it over the counter--otherwise I'd have it couple days ago --have to go through an agent ,they say> I'll be cranky with myself if I've made a wiring mistake --checked everything twice today so far-- But I'm an old bugger now ,so anything can happen--lol. Bruce Bushboy |
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Megawatt Man Senior Member Joined: 03/05/2006 Location: AustraliaPosts: 119 |
brucedownunder2, It is highly unlikely that you have made a wiring mistake, even if you are an old bugger - I am one too. If you took all the wiring off all the coils it would still cog. It's the magnetic effect only. You have increased the magnetic forces greatly, and even though the spacing is different, there still are plenty of positions where the magnetic force exerts its influence. If you actually drive it I'll bet you have a machine that can produce significantly more than using a standard F&P rotor, maybe 1.2 kW. Maybe there is a middle point at which the magnetic force trades off. For example, your previous neo rotors gave you plenty of power, I think I remember 600 watts? I reckon that a rotor that had the same number of neo magnets as the new F&P, on a 7 phase winding would give you the same power, or maybe a little more because the generated voltage is a little higher. Now while I'm on it, the concept of twin F&Ps on the same shaft, displaced by half a pole pitch to reduce the effect of cogging needs some examination. You will still get the same cogging force, but twice as often. The mill will still have trouble starting. If you turn it by hand the turning torque will seem smoother, because there's sre more bumpy parts in the movement closer together. If it was driven by Gizmo's ols VAWT, maybe it would be quieter, because the sound generated would be at twice the frequency and that may just be far enough away from resonant points of the mill. Keep working. All is not lost! Carefully drive your new combination up with a big electric drill to measure output. Then tell us the answer, please. Megawatt Man |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah I think both Clarence and Megawatt Man are on the money. The narrow magnets would increase cogging, they give a more peaky magnet flux, just the opposite of what we want to achieve with the 7 phase conversion. The stator poles are just a tad over 9mm wide, so your magnets need to be at least this wide or wider. And as Meggawatt man said, your output figures indicate that you may have a very powerfull alternator there. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Yeppa, thought long and clear about it now-----.The solution would be wider magnets .. Anyhow, bench is cleaned up ,stuff put away , frig restocked , so on to another project --- I seem to do things twice or three times lately -must be the retirement time available. Having fun in the Sunshine State. Bruce Bushboy |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Bushboy |
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| clarence Regular Member Joined: 27/10/2006 Location: Posts: 63 |
I was thinking that could work as well Bruce only I wasn't sure they would all fit, but I suppose even if the poles are nearly touching each other it should work, but once again as for performance I have no idea. having a look at a pic of the new f&p drum, the gap between the ceramic blocks appears to be about 5mm. whatever the actual gap is I reckon it would be a good guide to use for neo conversions. if the gap was 5mm, this would call for neo's of pure guess 11-12mm wide. this is all pure speculation and I am probably way off track. or you could try something like this. leave all the bottom mags in the drum and offset the top magnets all about 3mm eg. Its all great fun ------ | | | | | | | | | | | | ------ ------ | | | | | | | | | | | | ------  |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
yep, another way to go Bet we get there one day Bruce Bushboy |
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| clarence Regular Member Joined: 27/10/2006 Location: Posts: 63 |
I just completed a neo conversion 48 mags using 10mm wide neo's and unfortunately it cogs, but not overly bad. should be ok with large enough props. I still think 11 or 12mm neos would be better. |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Clarence. Do you have a standard old ceramic 56 magnet hub? If so, could you try that on the stator and let us know how its cogging feels compared to the 48 magnet neo conversion you have. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| clarence Regular Member Joined: 27/10/2006 Location: Posts: 63 |
hi Glenn, unfortunately not,but I did try an original some weeks back, and it definately cogged more than this experiment. and I should add that the neo's are in a brake drum,holden torana I think, and I am using the torana hub and bearings. It is incredibly sturdy. I made it this way hoping it should remain working for years. I will take some pics shortly. it's not so much hard to turn, but noticeably lumpy if you know what I mean? on another note, there was a bit of a wind squall today, and it snapped my 2 metre pvc prop in half. I think its time to consider furling. |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Hi Clarence, I sort of had the same minor cogging with my 3 phase Neo conversion--Not too bad ,concidering the gain in magnetic attraction- I just back it off from the stator a bit . But ,yes, we would do well to try a bigger mill with these neo conversion --and in my case be hopeful of some decent winds. Bruce Bushboy |
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| clarence Regular Member Joined: 27/10/2006 Location: Posts: 63 |
hi Bruce, on reflection, I dont think this neo conversion of mine is too bad. I can spin the rotor with one finger and fairly easily spin the thing with two fingers grabbing the 50 mm bearing cap, but it's still coggy. connecting one phase to a 12v 1 amp globe, lights the globe brightly with a slight spin. this is wired as 7p6p 1mm wire stator. the neo's are 10mm wide and 20mm long and only 3mm thick. the air gap is exactly 1mm. Ideally the neo's could be 25mm long to fully cover the laminates. the gap between magnets is exactly 6mm. unfortunatly as you can appreciate, this is a bit of a trial and error thing with this 7 phase thing. I have given it a lot of thought, and if I were to attempt to make a conversion with optimal decogging I would try and make the gaps between the magnets 4mm. but I should stress this is only theory, and it may help with cogging, but lose out in efficiency. I am going to have to try and make some accurate amp tests with my conversion asap. hopefully it will outperform a factory rotor, but if not, well its back to the drawing board I reckon. |
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