A Variac or autotransformer is something I've always wanted. They're an item I just don't see every day though in my travels. One day I did happen to come across one while I was shopping at a flea market. The fellow selling it wanted $5 for it which I thought was fair, so I bought it. Only thing was all I got for $5 was the bare Variac and a panel plate for it too.
In this project I had a real well I never moment that I hope I can share with everyone that reads this. Enjoy!
Step 1: Well Now I Have a Variac
Sure I'd heard about Variacs, or autotransformers as they are generically called I even had a fair idea what one did, but not exactly how it does it. Just what makes this gadget tick, and more importantly how do I hook it up?
It can't be all that hard can it? After all a Variac is just an adjustable transformer and I've hooked up plenty of transformers in my time. All any transformer is is just a coil of wire right? The five studs that stick out of the thing are obviously the connection lugs for it. Why I'll just get out my trusty multimeter and ring the thing out.
Well those were my thoughts at the outset of this project but once I began things quickly descended into what can only be described as chaos. those 5 studs yield 20 possible combinations of pairs of connections and I rung some sort of a reading out of every one of them!
The graphics on this page are digital reproductions of the tables I made on a piece of paper while I was in the initial discovery phase of my Variac. I made two of these, because of course there is a control on a Variac and these readings change as the control is manipulated. The numbers in the tables are Ohm readings I recorded measuring pairs of terminals to each other.
Measurements that are supposed to match and don't is because my trusty multimeter isn't the best multimeter I guess.