 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Windmills : Overdrive VAWT
| Author | Message | ||||
Greenbelt Guru  Joined: 11/01/2009 Location: United StatesPosts: 566 |
Something I dreamed Up I suggest many mags.then add coils til you run out of torque. air coils should be used to help with start up. "COMMENTS? 
Time has proven that I am blind to the Obvious, some of the above may be True? |
||||
Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
I would hate to pay your magnet bill, to cover 4.78 metres. I would think your rotor being smaller than your stator would be a issue too. Sometimes it just works |
||||
| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
Downwind; No this is not cheap but 60 cents a KWH is what you use to pay for the magnets! shushh Buy little ones. Take another look. The turbine itself is a smaller dia. this is where the overdrive discription was born. 
Time has proven that I am blind to the Obvious, some of the above may be True? |
||||
| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Ok i thought you was using an iron core stator and then it would be like driving with the hand brake on. Sometimes it just works |
||||
Perry Senior Member  Joined: 19/11/2009 Location: Posts: 190 |
Would this not require a 1.5 m dia steel disk and hundreds of magnets/coils? I don't understand the 60 cents/kw-Hr comment either. Perry |
||||
KarlJ Guru Joined: 19/05/2008 Location: AustraliaPosts: 1178 |
Thats our feed in tarrif for power fed into the grid. This is why we are all giggling about our (MY) projects. EG: F&P dual $1K+, inverter 1.6K+, batts 0.6K+, PL20 0.3K+ Tower $1K, digging and misc $1K thus for the sake of arguement $6K and yield of 1200KWhr/year $0.66c = ~$800 thus less than 10 year paypack as opposed to never! Luck favours the well prepared |
||||
| Perry Senior Member Joined: 19/11/2009 Location: Posts: 190 |
Oh cool, I get it now. Thanks Karl |
||||
| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
I can't answer this politely. Time has proven that I am blind to the Obvious, some of the above may be True? |
||||
| Perry Senior Member Joined: 19/11/2009 Location: Posts: 190 |
?????????? Then just answer it. Bear in mind I don't mean hundreds, I just mean lots, I was just exaggerating |
||||
| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
Perry; This is the Reasoning if any exists. In numerous places on this forum I read the remark that a VAWT has a distinct torque advantage over the HAWT, Its problem is that it turns too slow to be an effective driver for a generator . Gear boxes have been used but the friction of gears and bearing as well as oil seals pretty much takes away the torque advantage. When the cost of the gear box is added it becomes a why bother decision.. The above described arrangement could replace the gearbox at any desired ratio by mounting the Mag-Coil assembly at whatever radius.that will optimize your needs. Here is the comparison repeated from the drawing. W = Wind Speed, Meters per second X = speed of rotor shaft in turns per minute. Y = radius of coil-magnet configuration in meters. Z= velocity at Y, Meters per second. W =10 m.s. X1 F&P or similar HAWT = * Your numbers,, all will be different. X2 = VAWT ( 191 X2-1 = VAWT extended diameter (191 Y1 = HAWT Y2= VAWT (0.75 Z1 HAWT Z2 VAWT = 3.14 m. perimeter= 3.14 x 191 rpm / 60 = 10m.s. Same as wind speed ( Efficiency is calculated after the boat floats.! Z2-1( Extended perimeter VAWT = 4.9 x 191 / 60 second = 15.6 m.s. Being generous I will give the F & P a radius of 8 inches, 20.3 cm .= 64 c.m. perimeter,, 15.6 m.s. / 0.64 m.s. = 24.37 revolutions per second 24.37 x 60 seconds = 1460 RPM. In answer to your question, As drawn and described will require at least 81 - no more than 87 magnets. no steel disk required. Resin coated Aluminum ring to contain and space the Mags then secured to the blades to stiffen up the total assembly. I will not build one. I have built my home in a wind shadow with wind twice a year that blows trees down, November and late march. the rest of the year is the sound of silence. I realize there is more to generating power than cutting flux quickly but it is an important ingredient, With a high speed cut the turns of wire can be less to achieve the desired voltage , less turns = lower coil wire resistance . more room in the coil for larger size wire , this large size wire has less resistance which means more current will flow without overheating Now we have more potential power. When this is connected to a load the inductive reaction to the current flow tends to stop the approaching magnet and once the magnet has crossed center of the coil the polarity of the coil reverses which tends to attract the magnet back to center. Torque is required to overcome the backward forces the more power taken from the system , the greater the torque required to push the mags. past the coils. So because of this care must be taken when selecting mags and coil sets for any system. The VAWT above if so designed will be very sensitive to the loading at this radius. I drew the plan with dimensions to complement a larger machine ie; 3 meter dia.with a blade height of 2 - 2 1/2 m. a real grid feeder. it would not be cheap to build and must be built very solid to keep the Coil-Mag air gap uniform, lots of concrete and roller bearings attached to the Coil base footing to insure the true tracking of the rotor.but not contacting the rotor except in times of high wind stress or failure of a main rotor bearing. Somebody will build this one day and we will say, Yeah! I remember something about that. What a fiasco that turned out to be! 
Note; the Text is directed to people who are interested in RE but have no basic clue to why a generator needs power to give power.--------- Greenbelt Impressive picture for those who have never seen it Francis Turbine Time has proven that I am blind to the Obvious, some of the above may be True? |
||||
| petanque don Senior Member Joined: 02/08/2006 Location: AustraliaPosts: 212 |
Would a steel ring work better than a steel disk? Would the large inertia of a steel disk may make it slow to start? |
||||
| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
petanque don; HI ! 
Time has proven that I am blind to the Obvious, some of the above may be True? |
||||
GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi greenbelt, The higher operating frequencies that your machine would produce, will require special electrical consideration. I would think that with the technology available today, that a more efficient use could be made of the same amount of wire, aluminium and magnets, even at a shaft speed of 100RPM. Large dia rotating components are difficult to fabricate and balance for even modest speeds, like 100RPM. PS:- The shape of the magnetic fields in relation to the coil will play a major part in a successful design Gordon. become more energy aware |
||||
| Greenbelt Guru Joined: 11/01/2009 Location: United StatesPosts: 566 |
HI GWatPE QUOTE=GWatPE] Hi greenbelt, The higher operating frequencies that your machine would produce, will require special electrical consideration. I would think that with the technology available today, that a more efficient use could be made of the same amount of wire, aluminium and magnets, even at a shaft speed of 100RPM. Large dia rotating components are difficult to fabricate and balance for even modest speeds, like 100RPM. PS:- The shape of the magnetic fields in relation to the coil will play a major part in a successful design Gordon. Thanks for the heads up. As I said earlier, This is something I do NOT plan to build. Time has proven that I am blind to the Obvious, some of the above may be True? |
||||
 Print this page |
 |
The Back Shed's forum code is written, and hosted, in Australia. | © JAQ Software 2025 |
