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View Full Version : Axial Flux turbine at 10,000' with Clipper and Classic

Georgia Boy
6th August 2019, 09:54
Hello!

It has been a long journey but the wind adventure has begun. I have a turbine up and running. Currently has 8.2' blades from CMS Magnets. 4,000W AC Clipper and Classic 250. Now to get the wind curve in the Classic straightened out and see what this thing can produce. Here is a quick video of it up and spinning at ~6mph - not producing any power at that wind speed though. Would a larger blade set help produce power at those lower speeds or is that going to be dependent on the power curve?

https://www.youtube.com/watch?v=OHS3Ke9JtPU&t=6s
Rob Beckers
10th August 2019, 06:59
Very nice Georgia!

There's not going to be much power in the wind at 6 mph (2.7 m/s). If I use a rotor diameter of 15 feet (4.5m) and 40% rotor efficiency, there is only 77 Watt available at sea level. Once you add in the various losses of alternator, charge controller etc. there won't be much left.

A bigger rotor will of course produce more at any wind speed (goes up with the square of rotor diameter), but so will your headages in keeping the thing under control at the higher wind speed. As Heinlein put it "TANSTAAFL" (you can Google that one if you don't know it)...

-RoB-
Georgia Boy
10th August 2019, 07:16
Rob,

Thanks for the reply. I have actually been considering moving up to the 9.2' blades from CMS to capture some more low end wind, but was worried about the exact problem you mentioned. We have measured 50mph winds up there on the back porch so I am sure it's worse at the turbine. I DO NOT want to damage anything. It is a remote site and no one is up there most of the Winter so I have to stay conservative. With that being said, CMS says the 8.2' blades are good for a 725 watt turbine and the 9.2' for a 1,000 watt turbine. I do not know how accurate that is. I have seen axials on youtube make way more than 725 watts with the 8.2' blades (probably just answered my own question).

I will be there for two weeks at the end of September and will be upgrading the tail. I am doubling the size of the tail and making it out of a sheet of aircraft aluminum. That should solve my turning into the wind problem. I am just hoping there is enough wind over that two weeks to test the furling and get the power curve set for Winter. After that trip it will be on it's own for a while.