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  • Author Author: jw0752
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Hacking a Toroidal Transformer

jw0752

I have this beautiful Toroidal Transformer but it is 19 Volts and I need 24 Volts for my application.

 

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It has a nice big donut hole and I have plenty of 16 GA solid enameled wire so I decided to add a few more windings. The first step was to figure how many windings I would need. I used some lighter gauge wire and wound 10 windings, hooked up the transformer and measured the voltage. I had 1.7 volts for the ten windings so 29 windings should give me the boost I need. This can't be too hard, I thought. I made a loose coil of wire and kept winding it around and around until I had the thirty that I needed. Next I secured one end of the wire to one of the existing wires and started to work backwards. I pulled the wire as tight as I could and went around and around until I had worked my way back to the last wind. Here is what it looked like.

 

image

 

Now that looks simple enough but I am writing this blog to let my hands stop aching. That was really hard work. I had to wonder how they wind these transformers when they have to put hundreds of winds on them. I can't imagine what kind of machine would be able to perform what I just did with my hands. If anyone knows how they do it I would really like to know.

 

I next used some cloth tape that I had and began to wrap strips around the transformer to hold the windings in place and to protect the wire. Here is the transformer after this procedure.

 

image

 

Finally I figured out the correct phase so that the voltage in my windings would add to the existing secondary and made a good solder connection. A few more winds of cloth tape to polish things up and I was done. A test of the transformer revealed 25 volts output with 118 Volts input.

 

image

 

Now that my hands are rested I am going to go back and make another one.

 

John

  • in reply to DAB

    Hi DAB,

    If I had a slightly stiffer wire I would make a coil spring out of it on a cylindrical form and then screw the spring onto the transformer before tightening the winds one by one.

    John

  • in reply to DAB

    as a side note: stacking up laminated core plates, then winding transformers was a lab exercise when I was studying electronics.

    We didn't do the toriodal ones. There was a hand-operated device  that helped us.

    The closest device looking like that machine is this;

    image

     

    There is real value in having to calculate permeability of the core (ok: I forgot the right term) and calculate gauges and windings. Then wind the transfo yourself and validate its parameters.

    Kudos to my school and Mr. Schepers. Vrij Technisch Instituut Mariëndaal Diest.

  • John, you have some of the coolest toys to play with.

     

    They use special machines to wind toroid coils.

     

    As you found, doing it by hand is a real pain.  Pun intended.

     

    Now if you want to have some real fun, get some 30 gage wire and make a big step up transformer using the same core.

     

    You have a lot of magnetic field to play with.

     

    DAB

  • Nice (and patient!) work, John.

     

    Lifehack (works only for trafo's where you can get at primary):

    If you don't have enameled wire and you need a not-drastic change, you can remove some of the primary windings. Warranty void.

  • in reply to jw0752

    John Wiltrout wrote:

     

    They apparently measure off the length of wire needed onto the hoop and then reverse the direction and wrap it onto the core. Very ingenious and a lot easier than the way I did it. My hands and arthritis are still killing me.

    Yes I thought it was ingenious too. I'd not really considered how this worked for volume production of transformers before until you raised the question, definitely interesting to see how it's done.

     

    I'm very much looking forward to somebody (i.e. you image ) trying to construct some DIY version of this for a home lab image.

     

    On a more serious note, I hope your arthritis isn't playing up too much as a result and your hands recover soon so you can get back to building cool things in your lab! image