Shielding EMI from TOROID TRANSFORMER

Discussion in 'General Electronics Chat' started by lubnaan90, Oct 3, 2012.

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  1. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Hello to all,

    I am building a Stereo Power Amplifier with Dual Toroid Transformer (Each rated at 400VA). Each transformer for each Channel. I would like to confirm whether or not this method will be of any good in creating a shield between the Amp Boards & the EMI generated by the Transformers.

    I have made a Virtual 3D design to explain properly on how i plan to do it.
    I would put a Barrier between the Amp Boards & the transformer using 1mm thick Steel plate between them. The height of the plate will be exactly as the chassis wall, so that when i put the top cover of the chassis, it will create a closed enclosure for both the transformer from all sides.

    Will this method do any Good to shield the amp boards from Electromagnetic waves being emitted from the transformers? Or is it just a waste of time to make these Barriers?

    Best Regards,
    Lubnan
     
  2. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
    507
    Steel is a pretty good material for shielding magnetic flux so the barrier will help. If you still get too much noise you can add a second steel shield or add a better shield material like mu metal.
     
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  3. crutschow

    Expert

    Mar 14, 2008
    13,002
    3,232
    Torroid transformers have a very low external field (which is why they are preferred for audio amplifiers) so your shielding approach should be more than adequate.
     
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  4. chuckey

    Well-Known Member

    Jun 4, 2007
    75
    10
    Beware your screen can act as a shorted turn, make sure you put a thin layer of insulation between the top of the steel walls and the case's top and bottom. They also have a high inrush current so might blow a 10A fuse.
    Frank
     
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  5. Mitchell Electronics

    New Member

    May 20, 2014
    2
    0
    Copper foil is sometimes easier to work with then steel and can help
     
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,526
    2,369
    As mentioned Torioid's do not radiate like EI transformers, with two in proximity to each other you can also position one at right angles to the other to decrease it further.
    Max.
     
  7. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    Welcome to AAC.

    Congratulations, you have practiced the arcane art of necromancy, the revival of a long dead thread. Likely the OP (Original Poster) has solved his problem in the years that has passed, or thrown it away, or something.
     
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