Isolation Transformer...DIY or DIE?

[romansroad]

We're in the process of moving and I can't find my isolation transformer (as well as my variac and the left half of my brain). Anyway, in Alfred P. Morgan's "Boy Book of Electricity", published around, oh, 1929, I recall a picture of two transformers with identical secondaries being connected to create an isolation transformer of sorts. Here's my crazy, cheap idea. (Keep in mind the already established frugal Scottish heritage).

I have UPS's sitting around that people threw out because the 12v battery was more $$ than a new power supply. I saved them (like everything else!) planning to use the power components for something. What about connecting them back to back? I know there might be some voltage loss, and I haven't had a look at the secondaries, but they do put out some current when backing up the PC's. I have built a resistance soldering unit using a microwave transformer, and it works great. Rewound the secondary with taps for my voltages and it makes serious current flow. Actually miscalculated on the size of the working leads as they did get a bit warm even with 8 gauge...but that's another story....

So, will this be an episode of Home Improvment where my wife is calling 911 or is the newly dubbed "Tartan Tranformer" possible?

[Th3_uN1Qu3]

Re: Isolation Transformer...DIY or DIE?

Two UPS transformers back to back should do. PSUs are stressed more when the line voltage is lower, so it may actually be a good idea to do it like this.