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Forum Index : Windmills : VAWT, F&P, analog MPPT project
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| govertical Guru  Joined: 11/12/2008 Location: United StatesPosts: 383 |
New ideas take a while to catch on. just because your a GURU or forum administer does not mean your always correct :) |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
dual blades with transmission VAWT Dual blades added belt drive. Small blades attached on output of transmission. Large blades attached to transmission input. Hoping to remove load that the transmission adds to the system. 
just because your a GURU or forum administer does not mean your always correct :) |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
Video showing side just because your a GURU or forum administer does not mean your always correct :) |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
VAWT's do have a place, where reliability and simplicity outweigh efficiency. They are perfect for pumping water, where even a very slow rate of turning is still fully usable. Cheers, Tony. |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
power in the wind Hi, the above link calculates the power in the wind at different speeds and for different size blades. Basically I see two areas of power loss, mechanical and electrical. Hopefully the new blade configuration will address the power loss that a transmission adds to the system. The buck converter circuit with adjustable duty cycle that you helped me with solves the electrical power loss at the stator. This VAWT configuration is low cost, safe, and easy for me to fabricate. The goal is to have multiple VAWTs operating in parallel to produce electricity. Check the CalTech video on VAWT wind power farms. I am continuing to test and fabricate. I will post results when available. Thank you to everyone on this forum for their help and suggestions. just because your a GURU or forum administer does not mean your always correct :) |
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| BlueSmoke Newbie  Joined: 02/05/2013 Location: United StatesPosts: 25 |
Been checking out some of your builds GV, I can see that you do enjoy pushing the envelope on the fabrication process and in creating real works of art, great work. Your use of various colors (in your fab process) makes it very easy to see the sub-assemblies as each doing their own part within the complete assembly. What is the material(s) that you are using/ machining to house various components? Makes me think Rep-Rap but on a larger scale and, of course, with more robustness and precision. Keep us posted! BlueSmoke PS: I'm interested in learning more about the use of a Buck Converter to enhance the output. Perhaps I'll have some questions when I get to a point on my mini build were I actually get some output. |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
Hi, because my resources are limited the materials I work with are common and can be found at lumber yards and kitchen supply stores. The gray material is plastic composite decking board. Everything else is polypropylene kitchen cutting boards. A group at windgen.org have been working on MPPT controller projects for small scale wind turbines. The core circuit of the MPPT is a DC to DC step down converter with a variable duty cycle. If a microcontroller is used to control the duty cycle of the buck converter than it is called a MPPT controller. Turbine stall has been traced to the PMA's stator internal resistor. The higher the stators internal resistance the faster it generates heat as the RPM increase and stalls the turbine. By limiting the duty cycle of the Buck converter to 50% or less the PMA's reverse EMF does not generate as much heat and more power is transferred to the load and is not wasted as heat at the stator. Corrections are welcome. I have been able to verify this using my test circuit and manually operating the generator. I have also been Beta testing two other MPPT controllers and the results are same. I hope this helps, I look forward to your progress on your project. just because your a GURU or forum administer does not mean your always correct :) |
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| BlueSmoke Newbie Joined: 02/05/2013 Location: United StatesPosts: 25 |
Thanks for the information GV just what I was looking for. I was a generator mechanic in the US Army (Mobile Electric Power Generator specialist) but that was over 40 years ago. Since it's in my blood, I've managed to retain much of the interest in many things Electrical and Mechanical throughout the years but haven't made any great practical use of those fun times lately other than tinkering with various projects (wind turbines, electric bikes etc.)... I'm always yearning to learn more in these areas and enjoy seeing what others are creating, improving and using to their advantage. Never really delved very deep into electronics so don't have more than a very basic understanding of the principles but do enjoy learning more in this area as well. I see that you got an O-scope (although I just noticed that's over a year ago) to help with your testing ... I would imagine it will very much help see what's going on with your circuits and help you make a "better mousetrap". Best of luck in all, BlueSmoke PS: I'll check out windgen.org |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
http://www.youtube.com/watch?v=5LvWE1JscO4 Hi, the above video explains what the FEMM program is. The program is overwhelming but learning how to operate the program will help understand all the parameters involve. I wish there was a easier answer but I have not found one. just because your a GURU or forum administer does not mean your always correct :) |
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| BlueSmoke Newbie Joined: 02/05/2013 Location: United StatesPosts: 25 |
Hi GV, FEMM looks like a fun program in that it's a powerful tool to help understand things right from the start. It also appears to be beneficial in that it guides the user into thinking of things in terms of including all (or, at least, many of) the elements and conditions involved. The video helps, program seems intuitive and I'm a CAD user so perhaps I can grasp enough to learn something in using it. It will be fun to explore ... thanks for the link(s). BlueSmoke |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
Hi, summer time is a low wind or no wind condition at my location. I fabricated a pedal generator so testing can continue. 
just because your a GURU or forum administer does not mean your always correct :) |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
pedal generator I completed the pedal generator just because your a GURU or forum administer does not mean your always correct :) |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
I would hate to calculate the loss of energy through the drive chain, it would be huge. Remember a 1:1 ratio will always be far more efficient than a geared system. Basically you have taken a poor designed alternator for your purpose and adapted a gear system to make it work, well done on design, but low marks on a efficient use of energy. Pete. Sometimes it just works |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
CalTech Study Hi, thanks for the heads up on the efficiency issue. I am working a over voltage protection circuit to prevent damage to the MPPT circuit during high wind condition. The OVP should brake the turbine when triggered by placing a resistive load across the PMA. No wind, no power. The Pgen is just for testing the circuit and maybe burn a few calories.  just because your a GURU or forum administer does not mean your always correct :) |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
Hi, the F&P is low cost and easy for me to modify. It saves a lot of fabrication man hours. The low efficacy of is the F&P is solved when a power conversion circuit is used. The power conversion circuit can take the form of a MPPT circuit or a DC to DC converter with a variable duty cycle. Earlier test results revealed limiting the duty cycle of the power conversion circuit to under 50% prevents turbine stall. When I compare my test results with the VAWT power calculate at http://usvawt.com/cgi/windpower.cgi?h=5;hunit=0.3048;d=4;dun it=0.3048;Calculate=Calculate , my test results track the calculated values well for the size blades and wind speeds I have measured. Once a working over voltage protection circuit is created to protect the power conversion circuit, it will be possible operate multiple low cost VAWT in parallel to harvest higher amps at lower wind speeds. just because your a GURU or forum administer does not mean your always correct :) |
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| Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Perhaps?? Regardless of how you justify all the gearing and DC to DC converters and anything else you care to hang off it, you still lose every step of the way. Its a fact that every time you convert energy from one form to another you lose everytime, so every gear, every electrical converter, or what ever you add is just adding losses hand over fist, you should have worked out by now that you always get less out to what you put in when working with energy. Thats why keeping a 1:1 ratio is always the best solution. The F&P might be cheap but far from the best option with your design. To claim its a efficient design is far from the truth i think. How are you testing this to develop the output figures you imply is possible. Pete. Sometimes it just works |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
Hi, I not claiming it is a efficient design and I do understand what you are saying about power loss. I am less concern about efficacy at this time and more concern about what I can fabricate, keeping cost low, and using materials that are readily available. I am using a 12 volt deep cell as a test load. To test the PMA I have used manual operation and a drill press. To test the VAWT with different PMA's ; air core and iron core; I have a outdoors test station at my location for long term testing and for fast tests I mount the VAWT to a motor vehicle and do a road test. It is not my intention to post fails or misleading tests results and corrections are always welcome. After I find a working OVP circuit I will be able safely continue testing. Can you recommend a more suitable PMA for a drag style VAWT. Suggestions are always welcome. just because your a GURU or forum administer does not mean your always correct :) |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
As I have said before in this thread , with your skills and obvious access to a CNC router you should be doing an Axial Flux type alternator , wind the coils to suit your RPM range and if it overloads then you can couple the AC with series Capacitors to match the load, if needed at all . No need then for MPPT and all the other Bull Sh!t and quoting CAL TEK and USVAWT every second post . It would be so much easier than the amount of gearing you already cut out , but you seem to maybe have an aversion to working with a couple of steel plates , most of it can be done with your plastic chopping boards as moulds and templates. You may even be able to get away with ferites if the discs are big enough. The other thing I can not work out is why you actually need so much gearing , a 60S or 80s F&P will produce 12V easy at very low rpm if wired correctly , a 60 could be as low as 10rpm , you have what looks to be 6 x 3mtr high sails and these can not develop enough power with that much area to get 350W which is about what a F&P is generally good for, then maybe the alternator is not the culprit with the low efficiency problem. If it is stalling then Glenn explored The staggered stator Mods. Sure you can try and run the F&P at high voltage / high RPMs with gearing and adding in MPPT extra surface area and all the other mods you have tried and after all that if you are not getting better than 350W then what is the point, so far , and might be wrong you have not given any output figures ? The pedal power thingy is a work of art but is no different than wackin a F&P on a old scrap 10 speed Bike frame, but nice work all the same ... Are you a clock maker ? PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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| govertical Guru Joined: 11/12/2008 Location: United StatesPosts: 383 |
Hi, no I am not a clock maker. The increased cost of the Neo magnets have ruled out the axial flux PMA. Feel free to fabricate a VAWT 6' by 4' and follow your own advice on what to use for a PMA. Then we can compare results. New ideas take while to catch on. It is ok, you do not have to like them. Remember, it always starts out to a nice day. 
I added a threaded rod to reduce the wobble when pedaling. Continuing work on OPV circuit. This is just the project that I am work on. Thank you to the creators of the forum and allowing new ideas and projects to be posted and shared, you never know what new and exciting ideas may develop or where they will come from. Cheers just because your a GURU or forum administer does not mean your always correct :) |
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| fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
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