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400 Hertz at 120 V

Discussion in 'Power Electronics' started by colum, Jun 3, 2020.

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  1. colum

    colum

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    Jul 25, 2013
    I want to drive a Vibration meter at 400 Hertz and 120V and about 5 t0 10 Watts (a guess) I wonder if someone would suggest a circuit and if a 60 cy transformer can handle high Hertz
    This is going to be a onetime testing for several instruments and I would like to do it without spending too much....Many thanks....Jeff
     
  2. KMoffett

    KMoffett

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    Jan 21, 2009
    Link to your "vibration meter"?
     
  3. WHONOES

    WHONOES

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    May 20, 2017
    Is the 120V peak to peak or RMS.
     
  4. colum

    colum

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    Jul 25, 2013
    The only thing I know for sure is they are built like tanks and the technology predates the IC
    I tested 60cy and 120v units at household supply and at a square wave but all worked fine
    the amplitude of the voltage made a big difference in the swing of the indicators
    Jeff
     
  5. WHONOES

    WHONOES

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    May 20, 2017
    You will not get a meaningful square wave out of a mains transformer.
    It should be relatively easy to get 120V pk to pk from a purpose built amplifier. How much building are you prepared to do?
     
  6. shrtrnd

    shrtrnd

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    Jan 15, 2010
    I'd check military surplus sites.
    400Hz, as you probably know, is what military aircraft operate at.
    There's a lot of military surplus ground test gear designed for use at 400Hz out there.
    (And typical nobody hobbyists have no use for a 400Hz transformer, so they're not in-demand items).
     
  7. colum

    colum

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    Jul 25, 2013
    Thanks for the advice..I will check those sites
    So I guess a 60 cy transformer would not work well on 400cy
    Jeff
     
  8. colum

    colum

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    Jul 25, 2013
    These meters seem to not care if the sine is a pulse or square or triangle as tested on a 60cy meter the only that seems important is stability of the cy Jeff
     
  9. davenn

    davenn Moderator

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    Sep 5, 2009
    nope

    and you still haven 't done as asked and proved a photo /link for this vib. meter
     
  10. duke37

    duke37

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    Jan 9, 2011
    Why will a 60Hz transformer not work well on 400Hz?
    There will be some additional core loss but unlikely to be serious.
     
  11. shrtrnd

    shrtrnd

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    Jan 15, 2010
    I suppose in most applications a 60Hz Xfmr would work ok at 400Hz.
    My interest perks-up when somebody specifies an application, like 'driving a vibe meter'.
    What's the application, or is this just some test set-up?
    If you use a 60Hz Xfmr at 400Hz, I'd make sure I didn't exceed the Xformer input voltage, and I'd pay attention to the
    fact that you'd have less voltage regulation at the secondary output because emf increases. (Again, what's the accuracy needed
    for this application)
    I looked on-line, and if colum is in the US, 'Surplus Sales of Nebraska' sells a lot of different 400Hz transformers.
    Most people probably know 400Hz is used on aircraft to cut down on physical size and weight.
    I know colum said his application is a one-time test of several instruments, but my perked-up interest is in why, and what
    those instruments are being vibe tested for. Are these very heavily regulated aircraft instruments? Or just hobby-work?
    Because of the filters needed for operation of 60hz equipment on 400 Hz circuits, the power supply circuitry can become
    an issue because some types don't work correctly at 400Hz.
    I may be over analyzing this, but as I said, the topic perked my interest, and I thought I'd submit my 2-cents worth.
    Just some input for consideration (or not)
     
    Harald Kapp likes this.
  12. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
    There is a (imho) very good explanation on EDN what works, what not and which measures to take.
     
    hevans1944 likes this.
  13. colum

    colum

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    Jul 25, 2013
    Thanks shrtrnd. These meters were bought at a flea Mkt and are built so well and most likely USAF like you said
    I am trying to get them working as a hobby item and also to prove I can do it
    I have some good quality sealed Synchro motors that are 60 cy but were meant for underwater (was told) so they ran hot
    I changed them to a 120 cy and they worked fine but alot faster..I have been experimenting with Hz in lighting and motors for quite a long time but a steady 400cy is my last on the bucket list.
    Thanks for that surplus store info and I will check it out.
    I may have a whole new bucket list if they have a Navy Hz rate 1200 hz in some applications
    be well..Jeff
     
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