Good evening, I wanted to share the DIY story (2 years old now) on how I winded my first mains transformer starting from a broken one.
DISCLAIMER: I am a hobbyist, I do not claim my work to be professional or that this is the correct way to do it, this is just A way to do it.
All the information relative to this are well written and illustrated on my blog https://www.mimifactory.com/, otherwise this post would've become too long.
So if you wish to understand more please visit the link.
1) I started by taking the old transformer apart, removing the burnt copper windings and the lamination (being careful to not remove the thin layer of insulation on them, you WANT your lamination insulated to avoid eddy currents in your iron core and prevent power losses)
2) I winded the copper, using nothing but my hands and two whole spools of double enameled copper wire. At the end of the page in the link you can find the calculations of the necessary amount of windings, you don't want to exceed the max magnetic flux density of your metal and turn all that energy into heat.
3) Put the lamination back in, then used a vacuum chamber to evacuate the transformer and replace the air with insulating varnish
4) Drying, assembling and testing are required before using the transformer in the device.
I didn't have much hope this would work, but the device is still operational after two years and the transformer doesn't hum or vibrates, indicating that the vacuum and varnishing really did its job. The amplifier is a classic 35+35w 2SC5200/2SA1943 from the '80s recovered at the scrapyard. The smoke detector is always on, just in case...
In the webpage I included more pictures and an analysis of the composition of the metal core that helped to understand the parameters for the right amount of turns.
DISCLAIMER: I am a hobbyist, I do not claim my work to be professional or that this is the correct way to do it, this is just A way to do it.
All the information relative to this are well written and illustrated on my blog https://www.mimifactory.com/, otherwise this post would've become too long.
So if you wish to understand more please visit the link.
1) I started by taking the old transformer apart, removing the burnt copper windings and the lamination (being careful to not remove the thin layer of insulation on them, you WANT your lamination insulated to avoid eddy currents in your iron core and prevent power losses)
2) I winded the copper, using nothing but my hands and two whole spools of double enameled copper wire. At the end of the page in the link you can find the calculations of the necessary amount of windings, you don't want to exceed the max magnetic flux density of your metal and turn all that energy into heat.
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3) Put the lamination back in, then used a vacuum chamber to evacuate the transformer and replace the air with insulating varnish
4) Drying, assembling and testing are required before using the transformer in the device.
I didn't have much hope this would work, but the device is still operational after two years and the transformer doesn't hum or vibrates, indicating that the vacuum and varnishing really did its job. The amplifier is a classic 35+35w 2SC5200/2SA1943 from the '80s recovered at the scrapyard. The smoke detector is always on, just in case...
In the webpage I included more pictures and an analysis of the composition of the metal core that helped to understand the parameters for the right amount of turns.
