Your Questions About Wind Turbine Design

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The tip speed ratio ? (lambda) or TSR for wind turbines is the ratio between the rotational speed of the tip of a blade and the actual velocity of the wind. If the velocity of the tip is exactly the same as the wind speed the tip speed ratio is 1. The tip speed ratio is related to efficiency, with the optimum varying with blade design.[1] Higher tip speeds result in higher noise levels and due to large centripetal forces; stronger blades.
It has been shown empirically that the optimum tip speed ratio for maximum power output occurs at

dont know if this helped, but from what i understand you would want to use either a polar or cylindrical coordinate system ( v(t) = r (er) + r (theta dot) (etheta) + k hat …etc) to figure this out… I would have to dig out the engineering dynamics textbook, if you are still interested

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The turbine itself shouldn’t change, but the shape of the blades would change. Low speed winds are more efficiently caught by one blade design/cross-section than those of high speed winds (especially a crazy 300 mph theoretical… Which would tear the blades off…).

I’m not going to give you a big mathematics of geometry, but look at the wings of high speed birds, and low speed birds, and short sprinting birds versus something like an albatross that never comes down (well, seemingly). When it comes to the eventual commercialization of wind farming, I imagine that there will be one “standard” design to catch the “average” wind, but with other areas purpose designed for some unique type of wind that they get. Some are constant but almost immeasurable (but still farm-able), some are constant but brisk, like the one we have down here where the Pacific winds get funneled through a fairly narrow and long valley.

So again, no specifics… But look at birds, and yes, the blades would change. Actual physical design of the turbine electricity generator? Don’t know. Probably not.

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The shape or curve of the blade is also important since you want to minimize turbulence and maximize the amount of the wind velocity that is converted to force on the blade. You really need to find information on the design of aircraft propellers. This is not a question that can be easily answered here.

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I agree that troubleshooting the existing design is wise.

Recheck the magnets to make sure they all have the same polarity, as in the exposed faces are all North or all South. See figures 9 and 10 on page 12.

Check the direction that the wire in each coil is wound. They all should be wound clockwise (or all wound counter clockwise). If you accidentally flip one coil over, it will fight (cancel out) the voltage produced by another coil. Flip two of them over and those two will cancel out the other two, providing no net voltage. So it is important that they all be tacked down in the same direction. See figure 1 on page 9.

If you have a spare magnet and a volt-ohm meter, you can check the output of each coil as follows: Connect the volt-ohm meter across the two wires (it’s okay if they are connected to the LED; connect the meter across the LED if that is the case). Set the meter on the DC microamp scale. With the rotor removed, slowly wave a magnet across one coil. As the magnet approaches, the meter will deflect in one direction, and as the magnet leaves, the meter will deflect in the opposite direction. As you approach each of the four coils one-at-a-time, the meter should deflect in the same direction. If not, one or more of the coils are flipped.

If the meter didn’t deflect at all, then there is a break in the wire, or the enamel has not been sanded off of the ends of the wire sufficiently to expose the bare copper. Find the problem (broken wire by inspection, or resand the ends) until you get a reading.

If you don’t have a volt-ohm meter but your DMM has a microamp range (or the lowest DC current range), connect it and perform the tests mentioned above.

If you *do* get the expected readings, then the coils are working properly. Reassemble the rotor. Verify that the clearance between the magnets and the coils is small (say 1mm). Then connect the DMM with it set to the lowest VAC scale and try spinning it again.

If you have voltage, but the LED doesn’t light, then maybe there isn’t sufficient voltage to run the LED. White LEDs at low current levels require about 3.2Vdc to operate. Red ones take less, around 1.7Vdc. So you could try substituting a red LED and see if that helps. (Note: Although your generator produces AC and the LED uses DC, it won’t produce enough power to damage the LED when it reverse-biases the LED.)

Good luck! It sounds like a neat project.

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Yes, it will work, but not as good as an actual three bladed turbine/ propeller.

Wingman

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Yeah the amount of carbon dioxide sent into the atmosphere making one of these things is going to be a lot , they never mention that and i dont think this is about cash.
It isn’t going to pay back for 10 years in terms of the amount of carbon emissions it saves from coal protestations

i was told this by a university lecturer , i dint know how he knows this but he also mentioned that there are tidal power stations that are much greener but with currant technology they dont produce enough power

if we dont reduce carbon emissions by 100% in 20 years the climate will change forever destroying the rainforest’s polar ice caps and coral reefs

so those wind turbines could be a source of power even when there is a very small population left
they could help us repopulate in a mad max scenario.

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If it is load calculations it means the output power of the wind turbine produce..

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The problem is very similar to the design of an airplane wing, except that the design has to shift from hub to tip to account for the increasing speed across the air stream as the distance from the hub increases. Think of the turbine blade as a wing that produces its lift in the direction that produces turning force. You want to maximize that force while minimizing drag forces in the direction of the air flow. So the optimum shape is an air foil similar to a wing, but turned so that the blade moves away from the concave side of the wing as it ‘lifts’ around the hub. Since the rotational velocity is low near the hub, the wing needs to be thick and wide, there. At the tip, the rotational velocity is high, so the wing needs to be thin and narrow out there. This is very similar to how propeller blades are shaped, except, there, you supply the rotation and the blade makes the wind.

In principle, one blade with a counter weight could work as well as a higher number of blades, except that the counter weight only balances the weight of the blade, not the drag forces on it caused by the passing wind. So two blades are usually the lowest practical number. Then you have ot consider that every time a blade passes in front of the tower, its air flow is disturbed, and if there are only two blades, that is a big power drop, twice per rotation. For this reason, three blades are probably most common. But a higher number of blades can work, too, but this usually increases the cost more than it smooths the performance.

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Regards,

John Popelish

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Hey Wind, take a good look at Charles answer to your question, it’s worth reading several times. I have to agree that the Helix, or the “Darrieus Rotor” is really neat looking. It is far from an efficient design. This is exactly the thing that got wind and solar into so much trouble in the 70′s, the misinformation that circulated around and was accepted as gospel by everyone. The vertical axis wind turbine is one of the most inefficient wind turbines in the world. This is the reason you don’t see any power companies installing them in their expensive wind farms, they would never pay for themselves. The typical VAWT runs about 5 – 8% efficiency, a far cry from the typical horizontal 3 bladed model, at around 25 – 30 %. But don’t take my word for it, it’s getting your information form hacks like us online that defeats the entire point of research in the first place. Get to the non profit websites like AWEA.ORG or MREA.ORG, or better yet, take a trip to the old fashioned library and check out some books, like Wind Power for Home and Business, by Paul Gipe, or anything written by Mick Sagrillo. Mick Sagrillo has a fantastic discussion on just this subject at the AWEA website by the way, he is considered by people in the business to be the modern day guru on wind power.

Better than all these ideas, get a subscription to Home Power Magazine, look up the event calender in the back, and get to one of the many energy fairs hosted all over the place. We went to one 12 years ago, and actually listened to Mick and other experts talk. Today our home is powered by the wind and sun, and I’m the guy that teaches wind and solar power to the kids in the local school here, that is where it has gotten us. If I listened to all the online pundits here 12 years ago, we never would have tried, and then I would have been just another guy sitting around telling the neighbors that, “Wind power doesn’t work,” because a guy told me that online. Put a little elbow grease into it, it will be worth it in the end. Take care, Rudydoo