RS Relay humming - auto change over switch

Discussion in 'Motorhome Chat' started by terryway, Nov 21, 2014.

  1. terryway

    terryway Funster

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    Hi Guys,

    Been a member for a short time and have read many very interesting messages and articles. I was impressed with Techno100 auto-changeover project and undertook the same conversion to my MH.

    All was completed and works as expected. However when connected to the EHU the relay hums, not loudly, but not enough to annoy.

    My question is "is it normal for the relay to hum or is it a faulty relay".

    Thanks in advance for your comments

    Terry W
     
  2. eddievanbitz

    eddievanbitz Trader - Funster

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    A little noise can some times be heard but not sufficient to annoy. However we all have different noise tolerances lol

    You could always change it so that the incoming main (supply) is on the Normally Closed terminals, thus not energising the coil.

    Then when the inverter is turned on, the relay would be energised and switch the contacts across so it would only "hum" when the inverter is used
     
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  3. terryway

    terryway Funster

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    Thanks Eddiev,

    The sound is amplified by it being mounted on the garage wall, so I now remounted it on some rubber feet which has reduced the noise. I was probably more aware of the hum as I hadn't expected to hear it, but if they all emit a low hum then no problem. If it does annoy then I will , as you suggest, swap the connections. However I thing I'm content now knowing that the unit does hum.
    thanks
    terry w
     
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