Nice article, I appreciate your good work in putting down all the resources and finding during the process . Removing the EI CRGO lamination is not so difficult as you said , You can soak or apply kerosene or turpentine or any paint thinner by brush to the staked lamination for some time and apply some more till it completely soaks in.Press the staked lamination bunch by hand and if you see bubbles coming out when pressed it time to remove the lamination. If you dont see any bubbles soak for some more time.
To remove the lamination use a knife or a steel sheet of same thickness or less thickness when compared to the lamination thickness. The entire process takes 3 to 4 hrs but rewinding is a good option because you save a lot of money in our part of the world 40 Euros is very expensive.

Thanks for taking the time for sharing

Best Regards

Anand Palkar

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Hi Albert

As I told you, feel free to ask me questions. If I know the answer I will answer it. And yes, this is what I meant by saying about energy reserve of the coil. As for the chemical, I will ask for help from experts on the topic. Anyway burning is the usual method as regards the electrical motors (as I have seen), although this is against the internationally used common practice which always makes use of dissolving baths.

Best Regards

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Hello Anthony

Your warm and supporting comment is also a pleasure for me, encouraging me to continue sharing my experience with you (along with all the other readers).

Best Regards

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Hello Henrique

Thank you for your warm and supporting comment.

Best Regards

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Hello Mahmoud

Thank you for your supporting comment. As regards your question, keep in mind that I could not order a new transformer without having myself any idea about the output voltage and current of its second secondary winding. Therefore this work was mainly a matter of obtaining the vital overall information in order for me either to proceed in a repair or to order a brand new unit afterwards.

Regards

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Hello Randy

Thank you for your positive comment.

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Hello Albert

Yes, after the chemical dissolving bath it’s much easier (and of course easily feasible) to dismantle the core by removing its laminated elements.
After that the removal of the coils is also much easier, but the winding off process is unfortunately unavoidable. This is due to the fact that the bobbin has always stopping ends and therefore the coil cannot be removed altogether. It must be wind off turn by turn. For an organized laboratory that performs such tasks this job is easy. They put the bobbin in an axle passing through its core space a piece of wood having the same dimensions of the transformer coil (all cores are standardized and therefore these labs usually have an entire set of wooden artificial cores for this job). Then, this axle passes through the artificial core (across it) an it is then attached to the winding machine, only this time the electric motor is disabled and the technician winds the coil off by simply pulling the wire as the axle spins now freely. That’s all. In cases of very small transformers which have very-very thin wire in the primary winding, the alternative is to remove it by cutting it across the direction of the axle and remove it in layers. This is the easiest way. Nevertheless, as I have seen this process many times in the past, these technicians just because hate working with calculators and mathematics they always prefer to remove the coils by winding them of turn by turn and see their count on the mechanical or digital counter embodied to their winding machine.
I have many times opened even impregnated cores but I have never heated their cores. I did this only when dismantling ferrite cored transformers. You cannot open them without heating them.
Finally, instead of feeling yourself sorry, feel free to ask me what you want. This is no problem to me (if I know the answer)!

Best Regards

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Thanks again Paris for all the time you took to make a very interesting article about those so frequently everyday used transformers!
I didn't see your answer until now. Sorry for that,
but that's why I asked another question under my previous Post instead under your recent answer above. I could also ask you another question about how to understand the extra energy in a coil thing.
But I guess that the bifilar winding just means that you get the same coil twice and so at twice the Amperage. (3,2A instead of 1,6A)
If you ever do find out the chemical substance which is used to dismantle a transformer constructor you probably also can help Mark (from Australia) who asked me previously in a Post how to best remove old layers of varnish paint.
And thanks for the great article!

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Hi Paris, I've still got a material question left. Something that I wondered about all along, but that still wasn't physically mentioned. If the famous local transformer is able to re-align the transformer core, after this special chemical bath, is he then also able to open up the core? I mean: Can he then also remove the primary and secundary coils from the core, Without unwinding them first? Seeing your photo of the transformer it looks like he can. And both the primary and secundairy windings are wound on a separate plastic bobbin. That looks detachable. Since the core looks like a M that is closed at the bottom by a single underline.
And if you've ever done this task succesfully at home by heating the core to a temperature were the Glue gets kind of liquid? Sorry I ask, but I've also never build one before. And this 'Core' part somehow wasn't mentioned.

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Okay thanks Robert. So it isn't a program but a 'paper calculator' from the guys from ARRL. Clever because that one works without pc or batteries.

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