13-10-2014, 04:50 PM
An obvious thought occurs to me while reading through this: if you are in any way unsure about wiring this up, then do it via a lamp limiter. This will protect your variac, and you. Simples 
You may already have one. If not, it's definitely worth putting one together. Once your variac is correctly wired and working, you can use it on the output of the variac for all sorts of uses.
Example here: http://www.vintage-radio.com/projects/lamp-limiter.html
I'll admit that when I made my variac, I had a few troubles, and that cost me a few 3A mains fuses (luckily nothing more serious). In my case, it was insulation being breached by the terminals of the mains switch being too close to the input terminals. Dead easy to sort once I'd realised, but confusing at first!
You may already have one. If not, it's definitely worth putting one together. Once your variac is correctly wired and working, you can use it on the output of the variac for all sorts of uses.
Example here: http://www.vintage-radio.com/projects/lamp-limiter.html
I'll admit that when I made my variac, I had a few troubles, and that cost me a few 3A mains fuses (luckily nothing more serious). In my case, it was insulation being breached by the terminals of the mains switch being too close to the input terminals. Dead easy to sort once I'd realised, but confusing at first!
