[Greenbuggy]

So last night I did some horse trading and ended up with a motor I need for my mill project and a MASSIVE 3+kVA insulated toroid core, was told it came out of an X-ray machine that got scrapped out.

I had originally intended to use this Antec toroid transformer as the basis for my power supply. 50 Vac output = 70 VDC rectified for my servos and geckodrives. Antek - AN-15450

Admittedly I've never wound my own power supply or toroid transformer before (I did wind a HV transformer for a tig starter project a while back) and am a bit intimidated by the math involved. I also realize that I'm starting from the opposite end of "economy" that is to say I have a toroid core thats rated for roughly twice what I think I need as far as VA rating with a healthy buffer, I would expect most people to buy only the size they need not more and I'm curious how that may impact my windings, other than taking more wire to make a full turn.

I found this useful document http://www.free-energy.hu/pajert61/WindingToroid.pdf that details the winding of a toroid transformer process, but offers very little on selection of wire size, number of windings etc. I am under the impression at this size of transformer 1 turn on secondary windings is equivalent to about half a volt, that should be easy enough to figure out (~100 turns = 50 vac right?), what I'm concerned with is how I figure out how many windings and what size wire I need to make the primary to run at 220vac and not get too hot.

Thanks for any help you can give

[Al_The_Man]

I have posted on this quite a few times in the past.
But it is a fairly simple process, you first have to decide on the current requirements for your secondaries.
The math is very simple, resulting voltage is dependent on what the turns/volt is of the Txfmr.
As a general rule, 2t/v.
If you want to get it exact for yours, just wind on a small sec. of say 10 turns of small gauge wire and measure the AC on it, extrapolate the voltage for v/t.
Decide on the current rating for the principle secondary, small ones can be added separately for 5,12 or 24v if needed.
If the secondary is two high at present, turns can be removed, as long as the present secondary is capable of your estimated current.
With that size, I assume it has 240v primary, if it has both, run it on 240v.
Post if anything more needed.
Al.

[Greenbuggy]

With that size, I assume it has 240v primary, if it has both, run it on 240v.
Post if anything more needed.
Al.

Previous owner took all the wire off it so it has neither primary or secondary, just ferrite core with glass tape on it. I was wondering what size wire and how many turns I should expect to put on for a primary to run off 240V mains. Thanks for the help

[Al_The_Man]

Again the wire size of both primary and secondary is relative to your current demand of your system.
Primary is directly proportional to the secondary.
Calculate for at least 1.5 to 2 turns/volt, which means you will need 400-480 turns on the primary, no small feat to hand wind!!
Al.