Wiring a dual-coil toroidal transformer...

[mzungu]

I need schooling on toroidal transformer wiring, specifically the dual coil versions. I've recently purchased a dual coil toroidal transformer from AnTek Inc (eBay store) that has the following specs.

700VA
Primary 1: 115VAC
Primary 2: 115VAC
Secondary 1: 39VAC
Secondary 2: 39VAC

My question is how do I determine which secondary goes with which primary, or does it matter? My plan, for now, is to energize only one of the primary coils, but I'm not sure if I need to, or even how to, identify and use the proper secondary coil. If anyone could offer some assistance with this, it would be much appreciated.

Jonathan

[Al_The_Man]

If you do a search of the forums here there is quite a few posts on how to phase windings.
But I have used AnTek toroids and he gives the colour code normally?
What you do is take the pair you want to phase, for example the primaries, connect ONE end of each together and apply 120v power to one pri winding, you should have close to zero voltage between the open end and the other end of the primary you are using to power with.
The secondaries are the same way, if you get double the voltage then swap one end of one winding with the other.
After you have achieved zero volts, you can connect in parallel. If you connect in series and they are out of phase, no damage will result but you will get no output.
Al.
Al.

[vger]

Good post Al,
I might add that the usual reason for dual primary windings is so one can connect them in parallel for 115 V input, or in series for 230 v input. The secondaries can be connected in parallel for greater current capacity or in series for greater voltage output, or used individually if isolation is required.
Steve