Annoying 60Hz harmonic driving you nuts? Try this.

Discussion in 'Pumps and Waterflow' started by RocketRooster, 21 Feb 2013.

  1. RocketRooster

    RocketRooster

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    I have two Haleia return pumps sited next to each other in the return chamber.

    At first they were well behaved, but the last week or so they developed an annoying harmonic that only manifested when both were switched on simultaeously. It was a hum that was driving me insane.

    I tried shifting their positions, tying the return pipes together to create some tension, cleaning them, nada.

    Then - I had a brainwave. I switched the L/N polarity on the plug of one of them. Problem solved!

    At the time I was dubious that it would work, but it does imply that they are pulsing the water according to the AC waveform and that it can set up a harmonic.

    Thought I'd share for anybody else who is having this problem.

    This will probably not work for DC pumps.
     
    Last edited: 21 Feb 2013
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  3. shaunn

    shaunn

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    good idea but dangerous :)
     
  4. RocketRooster

    RocketRooster Thread Starter

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    It's AC - both wires give the same pulse but 180 degrees apart. So for analog devices it makes no difference. Some digital things like some power supplies and oscilliscopes and stuff won't like it.
     
  5. carlosdeandrade

    carlosdeandrade

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  6. RocketRooster

    RocketRooster Thread Starter

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    Once you understand the science behind it, it loses its ability to terrify.

    It would be nice though if we were on 115V instead though....
     
  7. butcherman

    butcherman Moderator MASA Contributor

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    so you turned the plug around?


    [​IMG]
     
    Last edited: 21 Feb 2013
  8. RocketRooster

    RocketRooster Thread Starter

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    The previous owner had fitted a three-pointer.

    (TWO POINT PLUGS ARE THE WORK OF LUCIFER'S SKIDMARKS).

    But basically it's the same thing, yes.

    Since there is no on/off switch or anything like that involved, there is no safety risk either.
     
  9. butcherman

    butcherman Moderator MASA Contributor

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    makes sense :) I too hate a 2 pin
     
  10. RocketRooster

    RocketRooster Thread Starter

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    I just had another idea - I have a vibration flow pump that sticks when you switch it off and requires an impellor nudge to get it going again. Going to switch the polarity and see if that helps!
     
  11. dallasg

    dallasg Moderator MASA Contributor

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    dude i mean this in the nicest way :) but you do bring some wonderful topics to MASA...
     
  12. carlosdeandrade

    carlosdeandrade

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  13. irie ivan

    irie ivan MASA Contributor

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    Such true words and so relevant to the hobby as a whole...
     
  14. Tiger eye

    Tiger eye

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    Hi @RocketRooster will this work on a skimmer pump that is making a humming vibration noise? It's been doing this for the last week about and it is driving me crazy.
     
    Last edited by a moderator: 26 Nov 2015
  15. RiaanP

    RiaanP Moderator

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    @Tiger eye
    last time RocketRooster was online
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    doubt he will answer you.
     
  16. Tiger eye

    Tiger eye

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    Hahaha ok thanks RiaanP. I got the skimmer sorted out. There was a salt blockage in the air pipe.
     
  17. Danielv

    Danielv

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    works like a dream, thanks for the tip:thumbup:
     
  18. WarrenElvis

    WarrenElvis

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    Just bear this in mind @Danielv and anyone else wanting to try this. With 2 prong appliances, live and neutral are interchangeable, because you can plug the 2 prong into it's socket in any which way, so you might say it doesn't matter.
    But it actually it does matter which way you wire AC plugs and devices. Most people will think that because its alternating that its the same both ways but it's not that simple.

    AC power in SA and most other countries comes from the supplier in the form of 3-phase. Each phase is has a common connection to the others called neutral, the Live wire in a domestic installation carries the high voltage whilst the Neutral line stays at or near Earth potential at all times. In practice, variations in the power being take from each phase cause the Neutral voltage to vary, but it normally stays within a couple of volts of Earth.
    Most equipment sold for example in the U.K. only has single-pole switching. This means that the on-off switch is only connected in the Live wire to the equipment. This is perfectly safe provided everything is connected correctly. The reversed polarity will mean that the switch is now in the Neutral line, and even if the equipment is switched off, the Live line is still connected. This now sets up the situation that even though the equipment is apparently turned off, inadvertently touching either the Live or Neutral wire will result in an electric shock. Besides the safety aspect some appliances such as induction motors will run backwards if you connect the power up the wrong way.

    Example : A 2 wire extension to a bed side table lamp with a switch on it.
    Wire it the wrong way and you can get a nasty surprise when you're changing a bulb even if the switch is off. Wire it the right way and you won't get zapped if you touch either neutral or live with the switch off.
     
    Last edited by a moderator: 26 Nov 2015
  19. Abc

    Abc

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    and dont forget tl mention that gettinv shocked sucks alot and with water you wouldnt want to play around
     
  20. Danielv

    Danielv

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    thanks for the tips guys,had my fair share of being shocked by pumps:blush:
     
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