Hi there,

I’ve been really enjoying the DIY projects section of this site. Today I set out to build an AC transformer using the tutorial. Sawed a few pieces of steel, drilled bolt holes, wound one layer of electrical tape to each bar, and wound several hundred turns of 28 AWG magnet wire to the taped section of each bar. All seemed well but I’m measuring 1 ohm between the terminal end of the windings and the steel bars, which I believe is called a winding short according to the tutorial.

The tutorial is clear that one should not proceed if such a short exists, but offers no troubleshooting steps to resolve it. Do I need to apply more electrical tape? I don’t visually see any way the windings is physically in contact with the bar except via the taped section, so I’m quite confused how there is a short at all. I would think the point of the enamel coating on the magnet wire is to insulate it, but unless I’m missing something, charge could conceivable flow through the copper, enamel, tape, and then steel of the underlying bar? Would love any links if I’m misunderstanding the science, but moreso would like to hear what folks would do to troubleshoot the issue practically.
Thanks!

 

Normally there is some kind of electrical insulation used rather than wire on bare metal, As in windings motors , there is insulation material from 'PressPahn' to compressed insulation paper etc.
The windings is then often dipped in motor insulation shellac.

 

Sharp-Corners on your Core will be your nemesis,
make sure there are no sharp-corners,
sand, or file, sharp-corners smooth,
then wrap the Core with 4, or more, layers of Electrical-Tape.
Sharp-corners will cut like a knife.
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