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Noisy UPS

Discussion in 'Electronic Equipment' started by [email protected], Jul 21, 2005.

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  1. Guest

    I've just acquired an older 1.4 kVa BEST Micro Ferrups UPS, the one
    with the huge and heavy ferro-resonant transformer.

    I changed the battery, plugged it in, and it works great. Runtime is
    excellent for home use. Just one thing though: It hums and buzzes
    like an old neon sign ballast. Almost unbearable. I may not be able
    to use it for home because of the noise. It's quite a buzz.

    Is there anything I can do to eliminate or minimize this noise?
  2. Dave M

    Dave M Guest

    Probably not... Ferror-resonant transformers are inherently noisy, especially
    those of several years ago. You might try opening the unit so that you can get
    to the big transformer. ( Remove battery connections first!!!) See if
    tightening the assembly bolts in the transformer offers any relief. If that
    doesn't fix it, there's probably one thing left to do... consider building a
    small housing for it and mount it outside the house. Run a wire from house
    wiring to the UPS, and another back into house to feed equipment.

    Dave M

    Never take a laxative and a sleeping pill at the same time!!
  3. Keyser Soze

    Keyser Soze Guest

    I'm assuming that when you say "...excellent for home use." that you
    may not have a 1kw load on the UPS.

    It's possible that the ferro-resonant transformer needs a minimum
    load to go into regulation without all that buzzing and humming.

    Try adding a 100 or 200 watt incandescent lamp on the output to see if that

    If it does then wire a lamp to the ferro-resonant transformer output
    before it goes to the UPS circuit. This will keep it happy when the
    mains are up and will not be an additional load when the UPS kicks in.
  4. als

    als Guest

    Check the cap to the transformer. Make sure that all bolts are VERY
    tight. The only time you should hear anything is possibly when the
    UPS inverter is running (i.e., no A.C. input), and then not much.
    I have a dozen of these things (1's, 1.4's, 1.5's, and some 5 kva)
    here, and they are all silent, except for the fan(s).
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