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BarkyJ
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Posted: 03 June 2018 at 9:36am | IP Logged Quote BarkyJ

brucedownunder2 wrote:
Good morning BarkyJ,

was thinking , have you thought about "down-wind" type of arrangement?.

The other type I remember is the "fold-back" type that goes horizontal in the strong gusts then settles to vertical to capture the wind strength . had a picture of one once ,will try and locate it.

that 3D printer is amazing ,imagine all the parts you could make ,mind boggles?.

Good luck with your project ,have a day off ,,take the kids fishin?,lol.

Bruce


Hi Bruce

Yeah I have looked at a few follower designs, but at this stage I have just opted for out right control, rather than anything self controlled.
Call me crazy, but this is just the direction I am heading in at the moment.
I have seen a few folding back furling systems, and then the normal fold to the side furling systems. Neither really appeal to me at this stage, but I may revert to one of them if this plan goes wonky.

The 3D printer is certainly great. The strength of the parts is not as good as if the parts were injection or rotational moulded etc, however it works good for what it is, and if you design the parts right then they can still be functional parts.

Day off doing some windmill and entertaining kids is the plan, yes. Want to get as much done physically this long weekend, before having to go back to work and things plaguing me and me not being able to action them :)


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BarkyJ
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Posted: 03 June 2018 at 9:45am | IP Logged Quote BarkyJ

Warpspeed wrote:
One crazy thought that comes to mind, is that if you are going to use a motor to turn the machine, why not rotate the whole mast as well ?

That could then place the slewing motor, slip rings and azimuth sensing all at ground level.

Less weight up there, and much better access for many of the parts.

The mast itself would need to be made pretty stiff in torsion. It should not be too difficult to mount bearings at the guy positions.


Hi Warpspeed.

That is certainly a neat idea.
The motor I have at the moment though is not heavy though.
Having something at ground level would be nice though, but once its in place and protected from the rain etc, anything that needs adjustment would in theory just be control wise, rather than physical.

The ID of the turrets vertical tube, is about 77.5mm and about 6mm wall, and when I got this steel I looked in the book and the next tube down has an OD just under this. So with a little dressing, they should run on each other nicely.
At this stage the idea is to cut a disc of teflon or another hard plastic, and just put it on the inside end of the turrets tube, and the pole will just run on that, rather than being metal on metal.

The plan is to get a 6m length of the mast's steel, and cut it in half an implement a hinge like many of you guys have done before, so I can fold it down to service it on the ground. But those details are still a Work In Progress.

Rotating the whole mast is a very interesting idea though, but would make for large bearing at the bottom, and a somewhat challenging task to stablise the mast too, unless there were the tether points up high running on a bearing of their own. hmm.
ill give this some more thought - thank you.
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BarkyJ
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Posted: 03 June 2018 at 9:47am | IP Logged Quote BarkyJ

Warpspeed wrote:
BarkyJ wrote:

Interested to hear more about these solar tracker actuators.

Solar trackers have one supreme advantage, they only need to move very slowly. You are going to require something much more powerful that can shift the whole machine around faster than fifteen degrees per hour !

A dc motor should work fine, but if its a simple analog servo system, motor power consumption may be fairly continuous because it will always be trying to correct back and forth for any play or lost motion in the system. Any flutter in your wind direction vane is going to keep the system rather busy constantly correcting.

The basic concept is certainly sound and offers some interesting advantages. I think this is going to take quite a bit of development to get it exactly right, and mounting the working parts at ground level might turn out to be a major advantage.


Yeah I certainly dont plan on running the motor constantly, making fine adjustments. I likely will take the average of the wind vane, and then make adjustments periodically, possibly more so at lower RPM and less so at higher RPM. But I still need to figure out that detail - but end of the day its just software.
It however will not be 1:1 wind vane to motor output thats for sure.

Cheers
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brucedownunder2
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Posted: 03 June 2018 at 9:56am | IP Logged Quote brucedownunder2

Yes, tube in tube is what I have used with success.

I did it this way ,the both tubes were about 3mm in difference internally and the other externally . So I got some plastic waste water pipe ,the stuff they use under your sink ,Etc. split it lengthways with a hacksaw,(one side only) ,then spring it open to fit the smaller pipe and set it securely with a couple of countersunk set screws.. Grease it well and it worked perfectly .

Bruce

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Warpspeed
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Posted: 03 June 2018 at 10:01am | IP Logged Quote Warpspeed

Quote:
The plan is to get a 6m length of the mast's steel, and cut it in half an implement a hinge like many of you guys have done before, so I can fold it down to service it on the ground. But those details are still a Work In Progress.


Should be possible to rotate that, and even keeping the hinge in the middle should also be possible, but the hinge would need to be very well engineered not to introduce slop at the hinge. Wide spaced hinge pins should solve that.

A heavy tapered roller thrust bearing at the base should be dead easy.

If its all thought through it may actually simplify things rather than add to the complexity.


Edited by Warpspeed on 03 June 2018 at 10:18am


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DaveP68
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Posted: 03 June 2018 at 11:14am | IP Logged Quote DaveP68

Hi James

The 6m length of the mast's steel you plan to use, will it be self supporting or use guy wires secured to ground anchor points?
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BarkyJ
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Posted: 03 June 2018 at 11:23am | IP Logged Quote BarkyJ

Hi David

Yep plan is to use guy wires.
It might self support OK, I am not sure, but the plan is the use guy wires just to keep things a bit more supported.
Still need to figure all that out too, as the ground it is going on is not flat, its on a bank, so I need to walk the land and figure out the positions of everything yet.

Guy wires seems like a safer option than self supporting, even if the pole ends up being capable. We shall see I guess.
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DaveP68
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Posted: 03 June 2018 at 1:36pm | IP Logged Quote DaveP68

All good. The whole project is coming along nicely from my armchair view

As per another discussion re the maximum amount of torque each stator will take, have done some more tests on a 1x12C Delta at various RPM/power levels.

At 500 RPM the stator output power was 539 W (192.5 V at 2.8 Amps DC) and got an input torque reading 12.6 Nm. A result I've replicated in the past and 82% efficiency.

Run it up to 575 RPM the stator output power was 622 W (192.5 V at 3.23 Amps DC) and the input torque increased to a maximum reading of 14 Nm. Drops down to 73% efficiency.

Run the test again at 1200 RPM (drill direct drive mode) output power was 770 W (192.5 V at 4 Amps DC). This is full stator saturation and the input torque dropped off a cliff all the way down to 7.5 Nm!!

I've never actually done any detailed testing on F&P stators outside what I considered their most efficient mode of operation. The big surprise was the stator was still operating at around 82% efficiency! The blades certainly won't want to operate for that long at 1000 + RPM...

There are plenty of comments on this website about F&P wind turbines going out of control when the core becomes saturated and other remarks like you can't put a short circuit on the output to stop them etc...

The point I'm trying to get across here is to let the stator(s) output voltage rise to level it needs to and not let the current exceed 3.3 to 3.4 Amps (2.8 amps is the optimum 1x12C Delta).

At high RPM the torque will stay in the 12-14 Nm range per stator and we should be able to avoid any unwanted saturation.

Anyway this latest information is to provide a better understanding of the operating envelope F&P stators and not intended to put anyone off using them on a wind turbine due this operating limitation.

We all learn something new every day. I'm sure plenty of others out there have been there done that in regard to whats posted above.

Edited by DaveP68 on 03 June 2018 at 1:37pm
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yahoo2
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Posted: 03 June 2018 at 3:28pm | IP Logged Quote yahoo2

Free standing poles with small turbines on the top are very vulnerable to rocking, it is quite difficult to tune it out.

the vortex of turbulent air behind the pole oscillates like a top loader washing machine and creates alternating lift on the pole. It needs a flow breaker that spirals down the pole or a couple of tensioning wires.





Quote:
Solar trackers have one supreme advantage, they only need to move very slowly. You are going to require something much more powerful that can shift the whole machine around faster than fifteen degrees per hour !


sigh!..... that is not how they work.

A plain old satellite actuator will move the shaft 3+mm per second at 5000 newtons. The solar actuators i have used will move a tonne and hold 2 tonnes. if you matched the linear reduction with a old drill planetary the most it would take for a full revolution is eight minutes.

there are plenty of options available with some scrounging and lateral thinking.



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Warpspeed
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Posted: 03 June 2018 at 3:50pm | IP Logged Quote Warpspeed

yahoo2 wrote:

Quote:
Solar trackers have one supreme advantage, they only need to move very slowly. You are going to require something much more powerful that can shift the whole machine around faster than fifteen degrees per hour !


sigh!..... that is not how they work.[/IMG]

So you could probably build a solar tracker that went from horizon to horizon in ten seconds.
But why would anyone need something that does that ?
Once it locks onto the sun path, fifteen degrees per hour is all you need to follow the sun.

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Madness
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Posted: 03 June 2018 at 4:20pm | IP Logged Quote Madness

You need to hurry up if it is leveling to avoid wind damage if a storm comes in quickly.

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Posted: 03 June 2018 at 5:10pm | IP Logged Quote yahoo2

A solar tracker would run for 3 seconds every seven minutes and park level in less than two minutes.

the challenge with a turbine is going to be tweaking the furl/wait/unfurl timings in hot gusty conditions.

I recall someone doing it with blade pitch control and it worked really well, I am sure it is on this 4m.

found it frans AKA Midwoud1 posted some detail on otherpower.com

active pitch control





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