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Forum Index : Windmills : My unorthodox Build

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BarkyJ
Senior Member

Joined: 26/04/2018
Location: New Zealand
Posts: 114
Posted: 10:20am 09 Aug 2018
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Rectified the motor and sensor placement issue today.

Motor is now mounted, encoder and home position sensor managed to utilise their existing brackets with only a tiny modification to the encoder bracket. These are installed again and working correctly.

Winch issue is partially resolved, got some M12 stainless welded eye bolts and installed them into the anchors for the winch system now, so I will finish this off on the weekend and hopefully get things back on track for a test run.
 
fillm

Guru

Joined: 10/02/2007
Location: Australia
Posts: 729
Posted: 10:42am 09 Aug 2018
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  Jarbar said   As a rare contributor due to Ill health, but a long time frequent observer I'll chance my hand at the cause of the fatigue cracks on phillm hub disk.On a previous build for karlj the RHS that Phil used for the nacelle had the side torn out of it in an upward direction.This destruction was caused by the gyroscopic force of the spinning blades needing to go somewhere. Caused by the constant and sometimes violent changing of direction of the mill head by the tail trying to track the wind.And the amount of overhang in front of the pole.(longer lever)

This causes the mill head rotating around the pole and the gyroscopic forces of the spinning blades to try inducing swinging up as it furls. This can be seen and felt if you spin a bicycle wheel whilst holding each end of the axle and then trying to turn it left or right.In one direction it will swing up and in the other direction down.

This upward or downward force is what I believe has fatigued the hub disk. If it is made thicker then the force is transferred to the next weakest point which was the RHS on Phil's karlj mill.A thicker walled tube was used in the replacement and boxed in. I can't seem to find the photo's that were on this site to show the torn metal.But that could just be my lack of investigation.

On a mill I made that was designed to tilt up out of the wind it would spiral madly around the pole trying to dissipate this force in a figure 8 pattern, and after many experiments,I designed a better furling method.

Lets see if my arm survives!!


I have got no idea what that has to do with this thread ... really , it is like 10 years ago, and FYI it had nothing to do with gyroscopic forces I welded the yaw pivot shaft to the heavy walled RHS and in high wind it flexed, the flexing caused it to eventually the crack fatigued on the weld line and then let go and allowed the turbine to go vertical, it was repaired by putting the The yaw shaft completely through the 100mm RHS and it never skipped a beat until the tower collapsed.

Same with the hub ... flexing will eventually find the weak spot..

Maybe the hand on the arm should give another person their dues, rather than point at me??

Edited by fillm 2018-08-10
PhillM ...Oz Wind Engineering..Wind Turbine Kits 500W - 5000W ~ F&P Dual Kits ~ GOE222Blades- Voltage Control Parts ------- Tower kits
 
gpalterpower

Senior Member

Joined: 19/07/2009
Location: Australia
Posts: 175
Posted: 11:39am 09 Aug 2018
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Hi barky, so the hub is pressed directly against the rotor and drives via the fingers which line up with the
Peanuts holes in the rotor. Is that right? Do you have any photos of that? Like to see them. I'm just wondering hour much push and shove those rotors can take. I know they are pretty rigid but if they flex a little they would cause a poling effect on the stator and burn out. There's only a very small air gap between the two. Just a thought.
On my mill, I moved the front rotor back a little which gave me additional room to mount the hub directly on to a 25mm section of the shaft
I had a 50 mm diameter boss welded onto the hub to take the full weight therefore leaving the rotor completely free to do its job.

Marcus
if it aint broke dont fix it!!
 
BarkyJ
Senior Member

Joined: 26/04/2018
Location: New Zealand
Posts: 114
Posted: 11:51am 09 Aug 2018
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Hi Marcus

Ill try and get some more pictures tomorrow/Saturday and post them.

yep, the hub is pressed against the rotor, and drives the rotor around with the fingers.
Not really any different to the spline turning the rotor really, in fact it might actually be better. The rotor cant warp or distort from this direction of movement from what I can tell, as the fingers are locked into the peanut holes. For the rotor to distort, things need to go inward or outward, but this is purely rotational, and fixed to the metal plate. If anything, it would prevent distortion of the rotor. I cant foresee issues with this, but as mentioned its still very experimental, but hopefully it works well.



 
gpalterpower

Senior Member

Joined: 19/07/2009
Location: Australia
Posts: 175
Posted: 12:14am 25 Aug 2018
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Hey Barky,
How's the build progressing? How you going with those photos there! Im interested in seeing some more pics and how it all goes together.
Marcus
if it aint broke dont fix it!!
 
BarkyJ
Senior Member

Joined: 26/04/2018
Location: New Zealand
Posts: 114
Posted: 06:23am 25 Aug 2018
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Hi Marcus

Sorry for the delay on the pictures, I have been overseas for work, and just returned in the early hours this morning.

The build is going well.
I got the blades on and tested in light winds, and was just testing all the direction logic for the turret control, auto/manual, park, etc etc.

Had a few issues with the turret motor and the wind turning the turret, so have changed to a worm driven motor now, and in the process of mounting that up.

My concerns so far is that my blades are only going to work in quite strong wind, and in the last month or so, we have only had light winds, up to about 5m/s peaks. So really the windmill is spinning and things are working, but its not generating any power. But it does seem to be following the designed spec, as we are not generating any real power until about 5m/s up to 10m/s, but I am just worried that I am never going to see that sort of wind, other than if a storm front comes over.
I have noticed that in moderate wind, the blades start to make noise, but in light wind they are silent. So they must be dragging to some degree, so that is another challenge to sort out.

So I'm not 100% sure what to do now, but I will continue on as is and see what Spring brings, as it might just be the time of the year.

Still got a bit of work to do before I can leave it up for a period of time but making good progress.

Regarding the photos, I will try to get these done tomorrow. Really sorry for the delay.

Cheers
 
BarkyJ
Senior Member

Joined: 26/04/2018
Location: New Zealand
Posts: 114
Posted: 12:23am 02 Oct 2018
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My apologies for a decent absence.
I was called overseas for work, and so life's projects ground to a halt.

I have had a bit of a play and looked at all the wind data I have, and really I am getting winds averaging 3-5m/s, and only get a peak of 10m/s in a blue moon.

The blades spin, power gets generated, but only briefly. I am never in a generating position for very long, so something needs to change.

Do I need more blades?

The turret positioning is working. I stay pointing into the wind, but the wind is often too weak, fizzles to 2m/s then comes up to 5m/s and back down again.

This setup was structured around 5m/s as being the start and going up to 10m/s, but I am seldom over the 5m/s mark for very long it seems.

Input welcome.

Right now the wind is about 3m/s, peaking up to 5m/s and dropping as low as 2m/s, so the generator is barely engaging any load, and my test hot water/element remains cold. Its doing nothing essentially.

Here is a few quick videos for some show-and-tell. Please give honest feedback, recommendations welcome.

Video 1
Video 2
Video 3

Thanks
 
Madness

Guru

Joined: 08/10/2011
Location: Australia
Posts: 2421
Posted: 12:37am 02 Oct 2018
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  Madness said   Turbulence will cause you lots of grief and the harder the wind blows the more turbulent it will be.

I struggled for a few years with a 1500W Dunlite up a 24 metre tower, strong turbulent wind would cause it to turn 360 degrees quite often. AFAIK you need to get at least 10 metres above anything nearby. I had a steep slope to the east and the blowing up it amongst trees was the worst even though the generator was at least 15M above them in altitude. A paper streamer on the end of a very long pole is one way to check turbulence.



If you can get a wind speed indicator on a very long pole and test it up higher I think you will find what you need to do.
There are only 10 types of people in the world: those who understand binary, and those who don't.
 
BarkyJ
Senior Member

Joined: 26/04/2018
Location: New Zealand
Posts: 114
Posted: 03:47am 02 Oct 2018
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OK thanks, but still doesnt really solve that I am not getting enough wind...
When its blowing, it spins up fine, but I am just not getting enough over 5m/s, so my load is not engaging. I am not having issues with it not being into the wind, I just dont have enough of it, and this is really designed for over 5m/s constantly, which I just dont have.
 
Boppa
Guru

Joined: 08/11/2016
Location: Australia
Posts: 807
Posted: 06:46am 02 Oct 2018
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I'd do the height check, its amazing how much difference the height makes to both the turbulence and the speed

Its best to measure (preferably over a long period like 12 months) before starting with wind, years ago I had the fun of watching a major wind genny site being tested, they had probably a dozen different sites within a few kms that had 'temporary' measuring masts up to gauge the local conditions before investing in a full site build (these were the big monster wind gennys- the nacelle was about the size of a container!)
 
brucedownunder2
Guru

Joined: 14/09/2005
Location: Australia
Posts: 1361
Posted: 11:02pm 26 Oct 2018
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How,s it going BarkyJ ?

Bruce
Bushboy
 
BarkyJ
Senior Member

Joined: 26/04/2018
Location: New Zealand
Posts: 114
Posted: 08:58pm 09 Dec 2018
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Been out of action for almost 2 months, had to travel overseas for work and only recently got back, and now silly season is kicking in. I havent done much more on the windmill, but hope to get it finished over the Xmas break.

Hopefully some more interesting updates to come in the next month.
 
sonny97301
Newbie

Joined: 10/08/2019
Location: United States
Posts: 8
Posted: 02:20pm 14 Aug 2019
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some late info.  do you folks realize that 5/mps  =  18 kph
that is a pretty brisk breeze, in my book.
 
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