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Forum Index : Windmills : Stator Windings placement options
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GWatPE Senior Member  Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Readers, My own efforts with different winding reigimes, with the same magnetic configuration, reduced the resistance of the stator, but not significantly the power output at the same alternator test conditions. With a bigger rotor/power input, then a higher output current could be drawn from the same magnet volume, at the same rpm. The lower resistance, lowered the stator heating for the same current, so a higher current could be drawn for the same power dissipation. Half the resistance, would produce half the half the total heating for the same current. From this we deduce tha we can double the current. Howevere this will produce twice the total heating. The ability of the stator to dissipate the heat is the same, so we can only increase the current to 40% more, and not double. If there is any asymetric current loading [eg a battery], then this reduces the overall performance as well. Adding more coils reduces the electrical losses by lowering resistance, but unless the power dissipating ability of the configuration is improved as well, then increasing the total power rating is not as good. This same problem occurs with increasing the voltage with more coils, to say double the power output. The more coils produce additional heating. My testing has concluded that with an already good electrical design, that increasing the power output is associated with either increasing the rpm, or increasing the size. Gordon. become more energy aware |
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Crew I just posted a reply to Gordon here in another thread. I made some claims, which may or may not be accurate; time will tell, but instead of letting the cat out of the bag, I've decided to let folks take a stab at what i've come up with. Click on the "here" link above and read the claim and the reply from Gordon and take a shot at it. This could be fun. To keep things honest, I'll PM Gordon with what I've done and we can all watch as each other puts on his thinking cap to solve the riddle. I will be honest and tell you I have not actually tried in part what I've presented. I've built rotors and stators and used these principles in other successful builds, so I know the theory is at least sound. It's just another way to do what we're all familiar with already. Study that .gif! . . . . . 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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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
[Quote=GWatPE]My testing has concluded that with an already good electrical design, that increasing the power output is associated with either increasing the rpm, or increasing the size. According to both my mentor as well as "Flux" from Fieldlines.com, Gordon's statement is the popular consensus. I, on the other hand, am not 100% convinced, but that's why I chose the handle "MacGyver", right? What I've done here is use the basic induction model and extrapolated (moved it forward) just a bit. Knowing that when a field passes a wire in a particular direction, it imparts a current in that wire also in a particular direction was key. When the same polarity is kept, but the direction of rotation is reversed, the current path in the wire is subsequently reversed also. Keeping the same rotation direction and changing the flux orientation will also reverse the current flow in the conductor (wire). I was hoping this might turn into a cool little "contest" of sorts, but with no replies in over a day, I figure it's time to say what's on my mind. So, with that being said, consider the following diagram. 
Dotted lines indicate "other side" or "back side of rotor". This represents a magnet-rotor in a wind-driven alternator in its simplest form. In the real world, there would of necessity have to be a flux-return pathway provided by either one or more additional magnet-rotor wheels or by iron plates with tabs facing each magnet on each rotor (a little complicated). In this example, there is only one magnet shoved through a hole in the rotor. Each magnet has a N and a S face and there is no flux-return path. One possibility, building a single rotor as is pictured here, might be to have an iron plate each side of the rotor, effectively "pulling out" the flux lines enough to cut through the stator windings, but this will likely cause more operational friction than it's worth. Still, it is a way to test the theory. I think I have a way around it, but I'll keep a tight lip for now. Note the little arrows and the direction of rotation. The current induced in each segment of the same conductor (coil) travels in the same direction as the others, thus no "cancellation". That little sign at the top, which says, "The Twist" was in lieu of a 'hint' given a couple people to see if they could come up with what I did without me actually spilling the beans. In actuality, the flux from one magnet will be through the air and back to itself. Only a modicum of flux would actually cut through a conductor, but this was drawn for simplicity; as a way of further understanding the process. In an actual "build" a flux-return pathway would be needed or we could expect little to no actual production of any electricity. Unless the individual magnets were GIBUNGAS (huge), their individual flux fields would extend only probably no more than a few millimeters off the face of each magnet. The real bummer for me is I have no way to build this contraption as my tools are all locked up for the next few months (complicated), so I can't build anything. If someone else would like to take a stab at it, be my guest. If anybody actually does want to tackle this, I'll be happy to coach to the best of my abilities. I think it has possibilities and will eventually build it myself. Comments? 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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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
The draw back would be the coil legs would need to be bigger to get the magnets to cut the field correctly and this would add more length to the wire in the coils hence increasing resistance. I don't see how this will give double the power just double the frequency, as your magnet field strength is only half that of two magnets exactly opposite each other. The problem with playing games and wanting others to guess what you are up to, is it adds a lot of wrong thoughts to the forum with miss understandings. Secondly im to old for games and will leave that to the other sex that are better at that than me.. Spill the beans or keep it to yourself i say. Pete. Sometimes it just works |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Pete Okay, point taken. I just thought it might be fun to banter. I may be misinterpreting frequency with power. I assumed (and you KNOW what they say about that!) 4 bursts of induction would create twice the power of the usual two. As for more wire, I don't think so. What doesn't show in the little drawing I posted is a dual-rotor ax-fx. In that case, instead of using two coils, it would be just one, albeit perhaps a bit longer to take care of both depth past the first magnet stream as well as being able to stretch to the back side of the first rotor and reach down inside the second gap, but when I drew it out, it looked like less. Of course, the true test will be to build it. Want the job? . . . . . 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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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Nope! Pete. Sometimes it just works |
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