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Forum Index : Windmills : Something new
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arewa Newbie  Joined: 24/10/2010 Location: NigeriaPosts: 11 |
Hello, I was doing some research the other day and discovered something new called BTPS from Honeywell windtronics. So i decided to give it a try but i'm still a newbie to wind generators / alternator, but what i designed speed up very fast even on low wind. 
it has 25 magnets around the wheel set on NSNS (but i'm thinking to fill the gap with 25 more) i've had alot of ideas regards to the stator design but havent made anyone yet. Main thing is how to design the second rotor??? Happiness starts with the begining of knowledge |
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| arklan Newbie Joined: 18/08/2010 Location: AustraliaPosts: 29 |
the thing with torque and using a lever, the further out u r the less force u need to move something (or in this case stop it) most turbines have the blades at the outside with the alternator in the middle becase the blades act as a lever to turn the alternator. with this setup the alternator on the outside will have a lot more breaking power especially with cogging, i see this beast not going too fast and needing higher start up winds. 10/10 for thinking outside the box tho this is probably better suited to hydro? |
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| arewa Newbie Joined: 24/10/2010 Location: NigeriaPosts: 11 |
This will give you more information regards to what i'm working on.. www.stargateturbine.com/pdf2/Honeywell-6500-Product-Sheet.pd f www.freepowerwindturbines.com/honeywell_wind_turbine.html Happiness starts with the begining of knowledge |
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niall1 Senior Member  Joined: 20/11/2008 Location: IrelandPosts: 331 |
hi Arewa very interesting use of a bicycle wheel there ....if it spun up nice and fast like you say ,there should be some potential to extract a little energy it , maybe enough to run a few of those bright leds or trickle charge some nicads if you doubled up on the magnet layout it,d make it easier to make a test coil and have some experiments ...a bike wheel has strength going for it so Arklans hydro point seems worth thinking about , torque and any kind of cogging is going to be an big issue the prop itself is small , so it might only make a few watts ....but a few watts is better than no watts at all ...  niall |
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Tinker Guru  Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Did you count the magnets right? There should be an even number of them  .
I think the concave shape of the bicycle rim would make a poor magnetic path. Just entertainment value this thing, IMO Klaus |
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| RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495 |
Not withstanding this criticism.... the magnets being on the outer extremity means their tangential velocity (speed) will be far higher than if they were mounted inboard. Since power production is a function of *RATE OF CHANGE* of magnetic field, surely he could use smaller coils to make the same power?? Regardless of the generator being in the middle, or at the periphery, if you take 10 watts out of the system, the wind power required will be identical? One could argue that the generator being at the periphery could make for an easier startup (if you use air-cored coils, no cogging) - becasue at low (start-up) speeds the voltage produced won't excede the battery voltage, so it'd be free-wheeling until it gets going? Strikes me as a potentially interesting design. Smaller, lighter coils and more of them probably makes for about the same total copper but in all probability a nicer output. Thinking even further outside the box for a moment - makes a self-limiting system possible. Imagine a centrifugal clutch design - springs pulling brake-pads safely out of the way - yet if the turbine gets too fast, centrifugal force pushes them out to limit the systems maximum speed. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi All it would need a return path between the magnets to make it work efficient, coil with iron core, it and would have huge cogging problems due to the large radius of rotation of the magnets. All the best Bob Foolin Around |
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| niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331 |
well...i guess thats the end of this thread .....or did experimenting suddenly go out the window ? you should look up some of Ed lenzs thinkings on air core stators Bob.... effiency isnt everything when it comes to an alt....coil with an iron core ...at the edge of a wheel ? have a look at Ed lenzs site Arewa ...it might give you some ideas niall |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Niall I would live to be proven wrong by some new approach to an alternator. I will have a look at Lenz to see if I can learn more. Bob Foolin Around |
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| arewa Newbie Joined: 24/10/2010 Location: NigeriaPosts: 11 |
Great ideas.. But the thing i liked about the BTPS (blade tip power systems) is they start powering up with as low as 2 mph. @Tinker : just figured out you were right.. but i'm now upgrading it to 40 magnets. *i also did a single test coil holding another magnet behind the coil with the wheel spinning in front but it didnt light up a single LED. too much cogging & vibration. I thought of puting about 40 coils in series on a metal sheet (close range) around the wheel while it spins?? Happiness starts with the begining of knowledge |
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| niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331 |
using the metal sheet for the coils might be a bit counter productive...it could finish up being a gentle eddy current brake ....the air core coil i think seems the best to experiment with ..... i,d be inclined to try the 40 mags ...balance it well and try 1 coil ...that,l give you a feel for it without doing to much work and time......a simple (mini) generator you might be able to mount the coil to the bike wheel forks in some way .... the heavy cogging and vibration was caused i think by you holding a stationary magnet close to rotating ones ......what kind of coil were you trying ? that extra mass is going to be tough on that small prop .....but have fun .... niall |
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| arewa Newbie Joined: 24/10/2010 Location: NigeriaPosts: 11 |
Have a look at this.. Link 1 picture something similar. see also.. Details .. link 2 Happiness starts with the begining of knowledge |
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| niall1 Senior Member Joined: 20/11/2008 Location: IrelandPosts: 331 |
this is the nearest i could get on the net to an actual bike wheel generator....cool thing about this is how easy it is to gear it up ....or down very strange vawt drive ...but it appears to resemble the honeywell http://www.youtube.com/watch?v=Pjai2SFBu-c&feature=channel theres some more info here ...coil layout stuff http://deckvawt.blogspot.com/ ps...i think theres a proper drive shaft in this one http://www.youtube.com/user/vortextower niall |
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MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Arewa I am Sooooooo sorry I didn't see this thread earlier. I did nearly exactly the same thing when I was 22 years old (40 years ago!). I will walk you through what I did, found and what you might expect from your rig. First off, I used aluminum blades, each cut the same size and fastened to the spokes by bending a little "tab" over the long, straight back side, the position of the spokes holding the blades in place. The front of the blade was a curved "scoop" and though it did capture lots of wind at start up, it proved to have too much drag to achieve any real speed other than the fact that the apex of the blades' curve was merely inches from the rotational center. It appears you are using ceramic magnets stuck to the steel rim. I did it similarly, but I digress. If you look at your magnets, they are likely a N face and a S face on the large rectangular sides, right? If that's the case, then the magnetic lines of flux are provided with a return pathway through the rim, but only on that one side. Similar to an "electric" circuit, magnetism needs a complete "circuit" (pathway in this case) as well. Your rig provides only half that pathway. To achieve closure on the return path, you will find it necessary to build an iron-core coil, which will "see" a N face at one side of itself while "seeing" a S face at the other side. This will work, but it will cog so badly, the thing will only turn in a typhoon or hurricane. If you were to back the pick-up coil away from the magnetic rim, it would have less chance to cog, but it will also do less work and therefore produce less current. I tried exactly that and came to my own conclusion that there had to be a better way. Back in the day, LED (light emitting diode) was not an option, so I used tiny Christmas tree light bulbs, which fired at 110 VAC in series, but there were hundreds of lights on a string, so an individual light bulb would light up with a volt or two. Spinning my mill in a gale-force wind (70 + mph) produced a soft, orange glow and that's all! It was fun, but as "research" goes, it was merely a "step" in the right direction; sorry. What you've done here is taken the first step of a fabulous journey. Peruse this site and see all the silly crap we've all concocted and you'll be several steps ahead of most. I've been lurking in the shadows until my divorce is "final" but when that happens (27 days more) I will again be back online and will pay better attention to new threads like yours. Your signature line says "Happiness starts with the beginning of knowledge" but I'm here to tell you that true happiness is achieved with understanding! By the way, none of us understand all we know about this stuff.
. . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| arewa Newbie Joined: 24/10/2010 Location: NigeriaPosts: 11 |
Hi Mac. I thought of the iron core. will surely try that. also i upgraded it 40 magnets. hoping it lights up a few LED's :) What i thought at first was to use a dynamo on the wheel but i thought it will not spin unless in heavy winds. so i came up with this Your absolutely right true happiness is achieved with understanding! Major problem in nigeria is lack of electricity so fuel consumption is a normal task to run a generator from dusk till dawn. Happiness starts with the begining of knowledge |
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| MasterCATZ Regular Member  Joined: 25/03/2011 Location: AustraliaPosts: 52 |
also been looking into BTPS type generator something A little different to try if I could buy one of those in AU i would have grabed one already :S about 5 years ago I had some CPU coolers from vantec that used that magnetic tip to spin the fan for the cooler ... from memory the damn thing vibrated heaps .. wish i knew where they ended up .. I know i tryed using one for a wind speed tester ... |
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