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transformer theory returns

Discussion in 'Hobby Electronics' started by gav, Sep 13, 2003.

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  1. gav

    gav Guest

    hello again,
    I've been doing a bit of reading and think I'm ready to try winding my own
    Anyone got a burnt out toriodal that I can pick up from somewhere in

    My gf won't let me spend too much money on this sort of rot.

  2. Rob Judd

    Rob Judd Guest


    Truscotts in Croydon have a selection of toroid cores, some are wound as
    filter chokes and could be easily modified. Cheap.

  3. gav

    gav Guest

    Thanks. I have their address and will check it out.
  4. gav

    gav Guest

    Am really looking to draw some power for this experiment. Need something
    around 150-300VA if possible.
    Are toroidals silicon steel like EI types?

  5. Phil Allison

    Phil Allison Guest

    ** Gav - you are a bit weak on terminology. A "toroidal core " is any
    core of that shape, a "toroidal transformer core" is the same as above.
    What you need is called a "wound GOSS strip transformer core".

    GOSS stands for "Grain - Oriented - Silicon - Steel"

    These cores are made for use in AC supply transformers and sometimes
    audio transformers - a single long strip of thin ( insulation coated)
    steel is wound to form a core that is shaped like a section of a cylinder.
    Plastic covers are then fitted so that enamelled copper wire can be safely
    wound around the core.

    When fully covered in wire the shape suggests a toroid - or a round
    cross section ring.

    .......... Phil
  6. Vermin

    Vermin Guest


    Now look into the theory of massive amounts of RF power through
    loosely coupled tuned transformers like this;

    Then see what yer missus says.
  7. gav

    gav Guest

    Ahh, thanks.
    The guy I asked in an electronics store said.. "There yellow, Like this..."
    So any Mains Supply transformer will be GOSS type.

  8. Mark Harriss

    Mark Harriss Guest

    Goss is plain old tranny silicon steel which has the grain
    structure aligned in one direction by rolling it in one direction during
    manufacture. Even in a conventional E-I tranny, the grain is aligned to the
    magnetic field for the three vertical legs but runs at right angles for the
    top and bottom parts of the transformer. Only in a c-core or a toroid does
    the mag field and the metal grain align all the time. This allows a higher
    flux density before the material magnetically saturates so you can then use
    less steel to make a transformer of a give VA rating. All GOSS allows you to
    do is make a smaller more efficient transformer with less iron losses.
  9. Phil Allison

    Phil Allison Guest

    ** Not so.

    GOSS is high grade transformer steel and the kind used for toroidal
    cores is better than E-cores use. No E-core tranny made has the
    extraordinary low magnetising current of all toroidals or good C-cores.

    ** Not so.

    It runs along the "I" piece in the oriented direction ALSO.

    all the time. This allows a higher

    ** C core and toroidal cores have little or NO air gaps included - this
    is the real secret of low I-mag.

    ............ Phil
  10. Mark Harriss

    Mark Harriss Guest

    From the Acesita website:

    Q: What is the main difference between the grain oriented (GO) and the grain
    non-oriented (GNO) silicon steels?

    A: The main difference between the GO and GNO steels is in their crystal
    strucuture. GO silicon steel has a texture called Goss, in which the
    crystals are arranged in the direction of the easiest magnetization
    (direção [001] - cube's adge), parallel to the rolling direction and to the
    cube's diagonal plan (110) and parallel to the plate's plan. This kind of
    structure turns the GO steel into a material with excellent magnetic
    characteristics in the rolling direction and makes it suitable to the use
    in static cores where the magnetic flow is similar to the rolling
    direction, such as the transformers. GNO steel doesn't have a texture and
    it shows similar magnetic characteristics in all directions. This makes it
    siutable to the use in machines where magnetic flow is constant changing,
    such as electrical motors and power generators.

    Yep thats true but it still runs at 90 degrees to the grain for
    about 30% of the magnetic circuit which makes it not as good as toriodals.

    What steel E-I mains power transformers have airgaps Phil?, Maybe
    in something with a DC current like a class A audio output transformer.
  11. Phil Allison

    Phil Allison Guest

    ** Mark, you a such a ***fucking idiot*** you cannot even figure out
    what the point is.

    Go test a toroidal and you will maybe learn something.

    Until you have - go masturbate yourself privately.

    ............ Phil
  12. gav

    gav Guest

    Thankyou mark and phil.
    The link was helpfull
  13. Rob Judd

    Rob Judd Guest

    Toroidals are a single molded construction, so nothing like E-I at all.
    The ones I saw were low frequency types, probably powdered iron
    material. At a guess they would handle your requirement.

  14. Phil Allison

    Phil Allison Guest

    ** Ones for AC supply and audio are nothing of the sort.

    ** Ambiguous, stupid and mindless.

    The OP needs 50 Hz capability - not 50kHz.

    ................ Phil
  15. Mark Harriss

    Mark Harriss Guest

    Quite obviously Phil you should be taking this
    problem up with the manufacturers of silicon steel as
    their explanation agrees with mine and not yours
    Truthful Phil.
  16. Mark Harriss

    Mark Harriss Guest

    No problems Gav, Some of the guys
    at would also be able to
    supply some transformer theory too, but
    make sure you put "off thread" in the title.

    Mark Harriss
  17. Phil Allison

    Phil Allison Guest

    ** You are the one with a problem.

    You are still masturbating in public.

    .............. Phil
  18. Mark Harriss

    Mark Harriss Guest

    OOOHH! OOOH!!! I am so cut down by your highly technical
    disputation of my assertions about the grain in GOSS being
    oriented along the axis of rolling. If I wasn't laughing
    so much I'd be inclined to compare you to a penis breathed
    felcher, Truthful Phil.
  19. Phil Allison

    Phil Allison Guest

    ** Are you on drugs, Mark ?

    Cos you are posting utter nonsense.

    Maybe you NEED some drugs and have not taken them.

    ADHD does need constant treatment.

    ............. Phil
  20. Mark Harriss

    Mark Harriss Guest

    Nah this is just a game for you where you try for the last post
    each time....I'll have to look up the Phil Allison FAQ to see which
    method number this is.
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