Thursday, October 29, 2009

Wind generator

Wind generatorHere's a picture of my wind generator in action.

The eagle eyed amongst you will see the tail has a home made extension stuck to it.

The issue I'm having is that the wind generator keeps turning out of the wind, for no apparent reason.

It's really frustrating, as the wind generator is not producing the power it should as it turns out of the wind, slows down then turns back into the wind and speeds up again.

There is no specific pattern to which direction it turns out, and no particular wind speed or direction either.

I've been working with the folks at Eclectic to resolve this. They have been extremely helpful, to the extent of replacing the whole generator for me.

I am now sure it's not the generator, but something in the setup on Lady Jane. But so far I just can't work out what the issue is.

I know it's not:

  • The cable, or for that matter any of the connections, from the generator to the batteries, as I've changed all that.
  • The connection, as this is all connected up securely and correctly.
  • The inverter, as it still faces out of the wind with the inverter disconnected.
  • The battery de-sulphinators, as they have been disconnected to test this.
  • Any of the boats 24V systems, as they have been isolated to help find the problem.
  • The voltage regulator, as this has been temporarily bypassed.
  • Any turbulence, as the generator has been moved to endure this is eliminated.

The best I've been able to do is to extend the tail, so the generator turns back into the wind as fast as possible. This maximises the power I can get from the generator.

Any ideas anyone?

16 comments:

  1. Anonymous2:31 PM

    I assume there isn't any active pointing mechanism like a servo and that it simply swivels on the top of its mast. If it simply swivels, I can't see any electrical issue causing what you describe.

    You've checked that the bearings and slip rings (or whatever) operate smoothly and don't bind. What is that swivel mechanism, and can it be serviced?

    Is the design well balanced front-to back so that it would not be sensitive to being mounted out-of-plumb? It does say it's designed for use on boats, and they do have a tendency to pitch and roll so you'd think it's design would handle a slight tilt.

    Didn't it used to work properly? What changed?

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  2. Fred (WWR)5:04 PM

    The only thought that I have is that it may be a blade balance issue which is sensitive to rotation speed.

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  3. Hi Anonymous

    It's a simple swivel mechanism, using slip rings. These are fine.

    The system is installed pretty much on the level, using a spirit level.

    As to what changed, the original generator had some plastic parts which melted, presumably in a big wind. These have been replaced with steel parts.

    Regards

    Tim

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  4. Hi Fred

    The blades, and nose cone for that matter, have all been replaced.

    Regards

    Tim

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  5. Anonymous7:04 PM

    The manual shows how to wire a switch to short-circuit the alternator and thereby stop the blades. It is not clear how the thing behaves when the rotor is stalled in this way. Would you consider disconnecting it from your batteries and temporarily shorting out to see if stalling the rotor can cause it to turn away from the wind?

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  6. Is the prop acting as a gyroscope in that its (maybe) fitted the wrong way round?( perhaps the blade contours differ from fromt to back?) causing a gyroscopic imbalance?

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  7. Anonymous3:48 PM

    Does your battery monitor affair monitor the windmill output current and voltage? Have you been able to identify any patterns that occur when the windmill acts erratically?

    Presumably when it points out of the wind, the generated energy drops off radically, so that would be visible on the log. Being able to correlate that to actual wind speed and direction from a regular anemometer and load/voltage on the rest of the 24-volt system would likely help your investigation.

    ReplyDelete
  8. Hey TZ. Check out www.trawlerpictures.net/


    Are you planning to join us headed south. Looks as if we will now leave day after Thanksgiving here in the states...Nov 25.

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  9. Has replacing the plastic parts with steel caused a weight imbalance issue so as it is now turning out of the wind. Did it work fine/ better before these parts were changed?

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  10. What about making the tail as
    large as the propeller ?

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  11. Fred (WWR)2:05 PM

    Tim,

    I was working on a an my Truck, (Lori in your language :) ), this weekend. I had the engine running to top off the battery since it has been setting of months now. It has a very powerful electric cooling fan that only runs when needed. When it does start, it draws 100 amps and then settles out at around 32 amps at 12V. Now what does this have to do with your situation?

    Well, during that cycle there is a definite noticeable load being put on the alternator which manifests itself in a change in the engine RPM. After it settles out, the engine then returns to its previous running RPM. Translating that to your wind generator, a similar condition aboard your ship would probably cause the wind generator to slow down. If the blades slow down, they probably would tend to turn out of the wind until they catch up to the speed they had been previously turning.

    Just a thought

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  12. Hi All

    Thanks for all the great ideas, and responses. Every bit helps.

    Sorry for the delay in replying to you, but I've been very involved on other projects elsewhere.

    After watching the stopped, with a piece of rope, generator for quite some time, I noticed that the generator seems very sensitive to slight changes in the wind direction. Caused by gusts or maybe turbulence of some sort.

    I now think that that sensitivity to changes in the wind 'flicks' the generator through the wind out the other side. The wind then flicks the generator back, and so on.

    The next step will now be to try to put a damper onto the wind generator, so as to stiffen it's resistance to changes of direction.

    The force generated by the wind to change the wind generators direction seems quite substantial, so I'm not too concerned that damping this motion will have any adverse effect.

    We shall see...

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  13. Have you considered the problem may be caused by mounting the wind generator on the edge of the boat? I would have thought that the hull would disperse the wind direction and make it blustery e.g. upwards and across. Have you tried mounting it centrally up higher?

    Regards,
    Jon

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  14. Tim,

    I couldn't help myself - I found the following manual:

    http://www.allsmallwindturbines.com/files/Ampair_100_manual_rev_Mar_2007.pdf

    Look at the pictures on page 7 showing land based installations. The Lady is a big boat and probably the top right picture (think tall steep sided boat) could be indicative of what is going on. The solution could be in the left "good" pictures middle and bottom, where the generator is mounted twice the height of the hull. Looks like mounting it on the front mast or a tall pole on top of the wheel house may solve your problem. You could probably set up streamers at various locations and heights and monitor the wind consistancy to find a good spot.

    Regards,
    Jon

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  15. Hi Jon

    Thanks for your post.

    Yes, the wind generator will have less turbulence mounted up higher. No question about that.

    It's normal place is right up high, on top of the mast. http://timzim.blogspot.com/2008/07/wind-generator-up.html

    Along the way, my original generator was replaced with one that was suddenly wind shy for some reason.

    Due to the effort involved in getting the generator re-mounted up top of the mast again, until this issue is permanently fixed there is no point in putting it back up there.

    Regards

    Tim

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  16. Jon

    I don't know if you saw this post? http://timzim.blogspot.com/2009/11/wind-generator-yaw.html

    Regards

    Tim

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