AIR X Knocking noise

Hi everyone,
Please excuse me if I make a few errors posting I am a "newbie".
I have recently installed an air x on my narrow boat in the U.K which seems to generate a reasonable amount of power 3 or 4 amps in a moderate wind.The problem is the turbine makes an intermitent knocking noise which sounds mechanical and appears to occur as the unit begins to charge.The bearings are new and it is not the yaw shaft as it even happens with the yaw locked.Could it be electronic? or is it something these units do? any ideas would be appreciated.


  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: AIR X Knocking noise

    They make a "barking" noise, in a gust, as the factory blade flexes, and spils air. That may be what you hear. But this is way past charging, and into nearly overspeed. Its really buzzing when that happens
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  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: AIR X Knocking noise

    look closer at the items near the blades because under higher winds some bending and stretching of those blades may occur that it could hit or, for better wording, may be to clip something as it turns. observe the blades themselves for that evidence of it clipping something. if it is clipping something, even if clipping part of the turbine itself, this could lead up to blade failure and that could be dangerous.
  • System2System2 Posts: 6,290 admin
    Re: AIR X Knocking noise

    Thanks for the swift responses.The noise seems to come from within the main body of the air x and even occors when I hold the unit in my hands and face it to the wind(not recomended on safety grounds). It seems to happen at what I would guess to be about 500-700 rpm.
    It may be better described as a clonk and happens intermitantly. Once running at high speed it stops however as its only on top of the boat the wind is fairly turbulent so as it slows down and speeds up again it clonks again (very annoying when trying to sleep below)

    Thanks for responses so far.
  • BrianellulBrianellul Solar Expert Posts: 95 ✭✭
    Re: AIR X Knocking noise

    I also own an Air-X and I too experience the same knocking noise from the machine. It's not mechanical because I have just taken the machine down for a routine inspection and it's fine... no problem with the rotor/yaw bearings etc.
    I stongly believe that the noise comes from a sudden braking of the rotor from the electronic circuit. It seems that periodically the Air-X brakes the rotor for a couple of milliseconds, maybe for the microprocessor to get some readings and then it's back to normal. In fact the noise is similar to the overspeed protection of the machine. When the air-X brakes due to high wind, the same knocking noise is trasmitted down the tower.

  • System2System2 Posts: 6,290 admin
    Re: AIR X Knocking noise

    Hi Brian, yes I think you are right it must be due to a large load being applied electronically but is this normal ? In one of the tests described in the manual (see below) it sugests as it begins to charge (over 500 rpm it should still rotate fairly easily) could it be what they describe as cogging and helpfully suggest contacting the turbine dealer if you have this problem (not helpfull when I'm in the U.K they are in the U.S.A and don't reply to emails). Has yours done this from new ? mine is second user so I'm not sure.


    "(3. At 500 RPM and above, the AIR-X marine should be charging the battery. You should
    begin to feel some resistance on the rotor shaft and the LED should turn on. The shaft
    should have a slight resistance to rotation, but should still rotate fairly easily. If the shaft is
    cogging (difficult to rotate), contact your turbine dealer or Southwest Windpower. Be sure
    your battery voltage is not high enough to activate the regulation mode during this test.)"
  • BrianellulBrianellul Solar Expert Posts: 95 ✭✭
    Re: AIR X Knocking noise

    My Air-X failed after just 5 weeks in service. The controller blew up. I had the manufacturer send me a replacment and it always acted this way. Can't remember what it did with the original controller.
    This cogging is very unusual since the turbine doesn't actually stops, if fact I spent some time looking/listening to this strange behaviour and I can only notice it when I'm inside since this knocking vibration is transmitted inside (my turbine is mounted on my roof). I strongly believe that it's something to do with the microprocessor software!

    Thinking about it, I'll email the supplier and will report back any feedback I receive.
  • System2System2 Posts: 6,290 admin
    Re: AIR X Knocking noise

    If I understand it properly the controller slows/stops charging to check the battery voltage, because when you think about it would be kind of pointless to check the state of charge while it is charging. The knocking is probably caused when this happens. If this is the cause then is should happen at regular intervals, if not it is probably some sort of problem.
  • rickeolisrickeolis Solar Expert Posts: 110 ✭✭✭✭
    Re: AIR X Knocking noise

    Mine (Non Air-X) has been making a knocking noise for months now, and I attribute it to the mounting hardware holding the genny to the pole. Just the smallest amount of play that may not be seen could still be heard.
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