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  1. #1
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    Stall on a centrifugal fan



    Hi

    I have a fan on a large AHU that is shuttering at approx 60% speed, has anyone ever experienced 'stall' on centrifugal fans? Both pulleys new, belts new and definantly aligned.

    Anyone input would be appreciated!



  2. #2
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    Re: Stall on a centrifugal fan

    Quote Originally Posted by bunda View Post
    Hi

    I have a fan on a large AHU that is shuttering at approx 60% speed, has anyone ever experienced 'stall' on centrifugal fans? Both pulleys new, belts new and definantly aligned.

    Anyone input would be appreciated!
    So bunda,
    Do you mean it vibrating like it's out of balance?

    Can only suggest you check fan blades intact, clean & not damaged.

    Check drive shaft is running true, as well as fan wheel.

    All supports & structure of it secure.

    Could also require balancing.

    If you speed it up past 60% does it come good?
    Last edited by RANGER1; 30-05-2014 at 10:36 AM.

  3. #3
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    Re: Stall on a centrifugal fan

    So running on a variable speed drive, up to 30hz fan runs perfect, between 32-35hz I have this issue then as it runs higher it corrects itself again.

  4. #4
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    Brian_UK is offline Moderator I am starting to push the Mods: of RE Site Moderator : and general nice guy
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    Re: Stall on a centrifugal fan

    Is it the fan, the motor or the inverter that is causing the problem?
    Brian - Newton Abbot, Devon, UK
    Retired March 2015

  5. #5
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    Re: Stall on a centrifugal fan

    maybe slow down the ramp up time- check the inverter is prog correctly for the motor size,rpm,flc etc- run it in hand at 50htz to test it

  6. #6
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    Re: Stall on a centrifugal fan

    http://www.pump-zone.com/topics/moto...-and-solutions

    Suggest skip the frequencies causing the issues.
    Last edited by RANGER1; 31-05-2014 at 12:41 AM.

  7. #7
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    Re: Stall on a centrifugal fan

    A large backward curve centrifugal will stall overload if discharge air is blocked or restricted.

  8. #8
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    Re: Stall on a centrifugal fan

    Had an issue like this on a trane unit, new inverter sorted it

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