Rewinding an autotransformer

[Stocker]

Can I rewind an autotransformer with only the wire that used to be on the "125V" tap and have that be sufficient impedance for the primary for a regular trasformer, with secondary wound over the primary? I know that bit of wire won't blow up my mains (having used it for a while) but am I missing something important here?

I am getting bits and pieces together for a BIG bench power supply. Thanks to DestroyerX et. al. and the rewinding transformers tutorial, I already redid the wall-wart that will power the panel meter.

Now I am on the main power transformer. This thing is a 1.5kVA porker previously used only to power a hammer drill that runs off 240V~. I opened it up and was not all that happy to see it was an autotransformer.

One side had taps for 100-110-125, the other for 160-220-240 and obviously there were 0V taps. I am thinking there is about enough room for about 62-0-62 windings on the bobbin on top of the 125 "primary"

~man~ that is a lot of juice!

[Stocker]

Thanks alot for all the input guys...

Anyhow, I finished winding it up today. I'll be sure to test it with the GFCI power strip!

[Stocker]

It LIVES!

I wired it up to a GFCI with some 24AWG leads so they would sublimate if the GFCI didn't catch a short first... Don't ask me how I know wire can sublimate...

Anyhow, I got the main secondaries within 20mV of each other thank God, at 52.8VAC, and there is another single tap at 32 volts and change.

Thanks again DestroyerX!

[Brian Donaldson]

Be carefull or the Eurosissys will get upset about your little experiment not having the little CE sticker.

[Stocker]

I can print up a sticker with part, serial and revision numbers with a CE logo on it at work if it would make anyone happy. Saaaay... That's not a bad idea anyway.

What, you mean a single fine strand of wire is not an acceptable substitute for a fuse?

Anyhow, I rigged up a minor blast shield just in case...the wire-vapor would have hurt nothing but my nerves.

Rest assured, the final product, whatever it may be that houses this beast, will have some SERIOUS safety precautions inbuilt.