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Forum Index : Windmills : flywheel
| Author | Message | ||||
| windtinker Newbie  Joined: 16/01/2012 Location: New ZealandPosts: 38 |
Hi Would a flywheel make much difference to a wind turbine. I'm thinking with gusted it would even out the power. How do you lot build your turbine to get low wind speed and high wind speed power. I've being thinking about using a drag type base with gears but if I get low wind speed, when it speeds up the rpms won't go up much. Thanks |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Thats a bit of a debated topic. Some people like to build ultra-light turbines thinking they will harness every little gust. But others think the increased flywheel effect of a heavier turbine will capture the gusts energy anyway as a slight increase in RPM, which is then converted to shaft power after the gust passes and the turbine gives up its flywheen energy. The maths is pretty close for each side of the debate. But, another way to look at it, heavier is usually stronger and easier to make, lighter is weaker but will furl better, less gyroscopic forces to deal with. More to say but its time to wathc the news 
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, I rescued one of those exercise heavy wheels once .. It's got the free-wheeling ratchet sprocket gear on it also. very heavy. I sort of guess it would be an advantage in some set-ups,,. I'm thinking with a big set of blades it would get a move on and smooth out the gusts of wind .Dunno, but betcha someone knows better than me,lol. ???.. Have fun , I'm off to my newly finished ,all weather/wind proof /warm workshop ,complete with bar.. Bruce. Bushboy |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Yeah I've got a treadmill motor with a flywheel on it, takes some time to slow down! A lot depends on the alternator, and where its running in its power band when the wind gust came long. If the alternator is running in its ideal sweet spot, then a sudden increase in RPM from a wind gust could drive it up into a less efficient part of its power curve. If a flywheel was present, then this RPM would stay closer to the ideal, so having a flywheel in this situation would mean a gain in Wh. But if the alternator was running way below its ideal RPM when the wind gust hit, then the flywheel free turbine would spin up closer to its idea and make more Wh than a turbine with a flywheel. Again, it depends on a lot of factors and beyond my maths. I dont think adding a flywheel would gain anything. For a HAWT windmill extra spun weight isn't going to help the furling one little bit. As a rule its best to keep the turbine weight down as much as practical, but not at the cost of strength. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| windtinker Newbie Joined: 16/01/2012 Location: New ZealandPosts: 38 |
You could probable gear it up or down from were the average wind speed is, it would solve the furling as counter rotating. I'm planing on building a vawt(live in town), but the rpms won't change much. Is there anything I can do to capture low wind speed and high?, or doesn't it work like that |
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shawn Senior Member  Joined: 30/03/2010 Location: New ZealandPosts: 210 |
Hi windtinker have you looked at the cap doubler arangment its your best bet and will outperform adding a flyweel! How did you get on with the wire? Shawn |
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| windtinker Newbie Joined: 16/01/2012 Location: New ZealandPosts: 38 |
Thanks I'm purchase a welder first, got the design mostly worked out, will proable post some pics in 6-8 weeks. |
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| windtinker Newbie Joined: 16/01/2012 Location: New ZealandPosts: 38 |
How does a cap doubler help, earlyer cutin? |
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fillm Guru Joined: 10/02/2007 Location: AustraliaPosts: 730 |
Very Basicly it splits the AC using AC caps or 2 dc back to back , then to 2 sets of 3 phase recs which are then seriesed together to double the DC . Have a read of "Gordons Cap Mod " on the home page . Do not expect it to work with small uF caps and make sure they are of suitable voltage of at least 2x max un loaded DC voltage . It can be X3 X4 X6 whatever you want. PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits |
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Don B Senior Member Joined: 27/09/2008 Location: AustraliaPosts: 190 |
Hi Windtinker, On the flywheel question, I would guess from theory that you would lose efficiency with a flywheel relative to a turbine with minimal inertia. My reasoning is that your most efficient operation is at the optimum tip speed ratio for that turbine. This means that the turbine needs to be able to change speed in strict proportion to wind speed changes to maintain its optimum tip speed ratio. The effect of a flywheel would be to delay turbine speed changes in response to wind speed changes, thus forcing it into a less efficient operating mode until it is able to adjust its speed to correspond to the new wind speed. Note though that this concern would really only apply if you could somehow achieve constant tip speed ratio operation, which is the seldom achieved holy grail of wind generator controller operation. On a practical note though, raising the extra weight of a flywheel to your tower would probably be more bother than it is worth. Regards Don B |
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MrDelanco Senior Member Joined: 12/11/2011 Location: United StatesPosts: 101 |
If the flywheel is placed up the tower with the blades it will decrease the efficiency. If the flywheel is placed in a position where it's kinetic energy can be infused into the power system it will help to continue the rotation of the power system's driving force. I use a flywheel in my system's design, it is built into my generator design that is separate from the blades, my system uses a drive shaft from the blades to the power system. MrDelanco:Project Videos It is not only too know what it does but to understand how it does what it does. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I cannot see that a flywheel would achieve anything that a large relatively high voltage capacitor bank could not do even better.... Cheers, Tony. |
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