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    Transformer winding, how to?

    Hi I have built this in a single core

    Click image for larger version. 

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    https://www.allaboutcircuits.com/upl...l-windings.jpg

    It is from the page https://www.allaboutcircuits.com/tex...-applications/

    To build the primary I took a piece of 20cm wire, then bent it at the middle (10cm) and fold it back so I can have a bifilar wire. Then I wound this bifilar winding on the primary. So the winding starts from the start of one of the wire ends, and then ends to the folded point, then continues backwards into the other wire end. The two wire ends are the connection points of the primary. The folded point is left unconnected.

    Do I make this right?
    Last edited by BradtheRad; 4th April 2020 at 23:22. Reason: Attached linked image
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    Re: Transformer winding, how to?

    If I understand right, you are trying to build a saturable reactor. The type shown in the first link can't be build on a single core. Sending current back forth through the bifilar winding has just just zero effect.



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    Re: Transformer winding, how to?

    The diagram is a saturable reactor (as described in the linked article). (AKA magnetic amplifier.) The dots indicate orientation of the windings. The DC side (control side) has its windings oriented so as to suppress AC induced in them from the AC side (power side).

    Seems as though you wound the DC turns correctly. The article states you can have a single core despite the diagram showing two separate cores.

    This phasing of control windings can be accomplished with two separate reactors as shown, or in a single reactor design with intelligent layout of the windings and core.
    Click image for larger version. 

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    Evidently the two halves of the AC cycle (positive & negative) allow proper flux building and collapsing, as well as the effect within the windings.



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    Re: Transformer winding, how to?

    Quote Originally Posted by FvM View Post
    If I understand right, you are trying to build a saturable reactor. The type shown in the first link can't be build on a single core. Sending current back forth through the bifilar winding has just just zero effect.
    I thought so. But I read these "Ferristor" scans and they show the control windings onto the same core. That is weird.
    Professional engineering is the top, but amateur engineering is more fun.
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    Re: Transformer winding, how to?

    you need an EI core at least with wdgs on the outer legs - as well as the central leg ...


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    Re: Transformer winding, how to?

    Quote Originally Posted by Easy peasy View Post
    you need an EI core at least with wdgs on the outer legs - as well as the central leg ...
    I think you are right. It can't be done in a single toroid. How about a binocular, using it as an ei core??
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  7. #7
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    Re: Transformer winding, how to?

    Yes, using 2 x toroids is possible - just a bit untidy looking ...



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