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Step 2Prepare the Transformers
Chop and and knock out the secondary (thin wire) windings.
Don't nick or damage the primary windings in any way.
If you do, you could create shorts where two windings conduct to each other, allowing electricity to bypass certain parts of the coil, making effectively a smaller coil, and creating something different than what you expect at the output. Or, you might chop the connection entirely, ruining the primary. So do your best to keep it intact.
Don't nick or damage the primary windings in any way.
If you do, you could create shorts where two windings conduct to each other, allowing electricity to bypass certain parts of the coil, making effectively a smaller coil, and creating something different than what you expect at the output. Or, you might chop the connection entirely, ruining the primary. So do your best to keep it intact.
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Also, do NOT insulate bare copper with electrical tape to make it insulated: your inductors will be vibrating and getting knocked about (no matter how careful you are) and the tape will eventually slip and create a short somewhere.
Be safe and buy some heat shrink tubing or buy new wire. It really won't cost much.
Further, "new wire" for transformer windings IS enamel coated. There is a catch though, when you are winding wire on an existing welded-together E core transformer it is very easy to scrape the wire against the metal core which could scrape off the enamel (or other *painted on* insulation).
Also, don't step on cracks or cross a black cat's path. ;)
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If you do it this way, just watch out for grounded center taps in the HV side windings. if you run into these, just make sure the laminations themselves are insulated. Don't lay two center tap grounded transformers on your steel welding table. they'll either short out fantastically, or magnetize pretty well opposite each other and possibly collide.
I've made them both ways. I one of my friends had an addiction. He couldn't not pull over and pick up junk left curbside. He made a tidy profit stripping stuff down and selling the metals and or parts for scrap or on e-bay. I told him Eric, how soon can you get me 6 intact microwave transformers, he said Well, gimme a week. He had them in 3 days. I rewound two with 8ga THHN wire in the HV winding space, and two with it in the 120v winding space. The ones in the 120v side produce substantially more current, good for welding thick stuff, or carbon arc torching. The two on the HV side produced more voltage at less current, good for small gauge steel and aluminum (yes, you can arc aluminum, no, its not pretty...) The other two transformers ended up in a crazy steam-punk/mad scientist crossover Jacobs ladder that could be used as a bedside *lamp* and ozone comb sterilizer. :)
Oh, and definitely save the shunt plates. you can take them out later to adjust to your tastes (I was accustomed to welding with "real" commercial welders, so I adjusted mine to match) As this is how the old Lincoln Electric buzzboxes regulated current, the crank on the front moved the shunts in and out, and the voltage adjust just switched taps around.