small insulation transformer (10W@230VAC)

Discussion in 'The Projects Forum' started by sveindaniel, Feb 16, 2011.

  1. sveindaniel

    Thread Starter New Member

    Feb 13, 2011
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    Hi

    How small can I build an insulation transformer with 230VAC@10-15W input and 230VAC output?
    I would also like it to have a 3V or 10V output in addition to the 1:1 output. I understand that it will no longer be called an insulation/isolation transformer, if it has two outputs with different voltage.


    Kind regards
    Svein Daniel
     
  2. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    231
    They are all "isolation" transformers if there is no galvanic connection between the primary and the secondary. How about two step-down transformers, secondary-to-secondary...230VAC-to-10VAC connected to 10VAC-to-230VAC. Take your 10VAC off the first secondary and 230VAC for the second primary.

    Ken
     
  3. sveindaniel

    Thread Starter New Member

    Feb 13, 2011
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    0
    That's smart, thank you.

    But the storebought transformers get too big at the necessary VA.

    Could I save space by making two small step-down transformers, and connecting them like Ken suggested?
     
  4. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    I doubt that you will be able to make a transformer for a given rating smaller that commercial ones. For line frequencies of 50-60Hz the size is pretty much directly proportional to the VA or wattage rating. What are you trying to do...the big picture?

    Ken
     
  5. sveindaniel

    Thread Starter New Member

    Feb 13, 2011
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    OK, thanks for advice.
    I am trying to make the electronics for a drinking water ionizer as safe as possible, while also being compact.
     
  6. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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    Post your circuit, maybe it will help in solving your design issues. :)

    Ken
     
  7. sveindaniel

    Thread Starter New Member

    Feb 13, 2011
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    Thanks, that's kind of you.
    I'd love to, and I already did. But the thread got shutdown because the circuit got power from the mains.
    Note that the posted circuit was just for figuring out how to drive the FET, so for simplicity I stripped it for everything else, like transformers, current limiting resistors, fuses, switches, bells and whistles.

    You can get a quick idea of my circuit if you find my other thread.

    Now I have figured out a fast and really simple FET driver, so the next thing on the agenda is securing the circuit. I can post it in another thread in anyone wants it. It generates 300V pulsed DC with (hopefully) about 10ns rise and fall times.
     
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