Toroidal 2 coils in parallel?

[stdly]

I want to buy a toroidal transformer from the guy on eBay it is a dual coil. It is a 31+31V 500VA to make a 42vdc 15a PSU.

I wonder if I can run both coils in parallel to get 120 in 31vac 15a approximately out.

If I run them both in series I get 240 in 62vac 7.5a out is this correct.

Can you do a combination of either to get say 120 in 60 or 30 out or 240 in 60 or 30 out.

I did try to find this on this forum before I asked.

Steve

[miljnor]

Not sure How to phase the AC "safely" but yes you can although your output is 1.414 so you will get 43.8vdc out of the bridge after the cap. Also 500va is 500va so you will get closer to 12 amps.

I am not an expert however so hopefully someone else will chime in and confirm this.

[ViperTX]

The input can either be 240 or 120....the output can be used in parallel to get the max. amps.

[miljnor]

Thats right!

Don't know what I was thinking on the phasing AC part. On the DC side you need a Volt meter to make sure you get the phasing correct, otherwise you could have some white stuff come out!

[stdly]

Thanks guys!

Michael
I did read a post here about the zero voltage reading to get the phasing correct and to check if the windings are matching.
How did you get the 12 amps? Remembering I am not an electrical guy.
The same transformer on hammonds site says 16.66 amps for the 500va in parellel.

I thought that the windings might not be an issue with the toroidal transformer?
Steve

[Al_The_Man]

I think Michael was using the DC for calculations?
The VA rating gets rather involved once you start adding capacitance after a bridge rect. and running the supply at the rated peak current (which probabally does not happen all that frequently).
Larger capacitance can actually push the required VA up for a given load.
But basically your toroidal transformer secondary is probabally wired bifilar, which means the secondary windings are pretty much balanced so paralleling should be no problem, as you mention, there are several posts regarding phasing.
It does not matter wether you use 120 or 240v input as long as you use the correct primary, nothing else change.
Al.

[stdly]

I was looking at this pic from a post here http://users.adelphia.net/~javamoose...atics_Rev3.jpg
If I am understanding this all, JavaDog has his toroidal hooked up parellel in and series out, 120vac in and 1 x amps, 2x volt out?

I looked on ebay because I read a post reply from Al the Man saying he buys them on ebay. Thanks Al.
This is the transformer.
http://cgi.ebay.com/ws/eBayISAPI.dll...MEWA%3AIT&rd=1
So it looks like red to red and black to black input and green to green and blue to blue output to get 120vac in and 30va 12? amps out.

Also the formula Michael used was what I was hoping for so I don't have to ask dumb question.

Steve

[ViperTX]

You can check the phasing of the secondaries by connecting them...hook up a voltmeter....apply voltage to the primary side...if the voltmeter ic close to zero VAC....reverse the secondary windings.....and check again.

[miljnor]

I think Michael was using the DC for calculations? The VA rating gets rather involved once you start adding capacitance after a bridge rect. and running the supply at the rated peak current (which probabally does not happen all that frequently).

guilty as charged!

that is why I was hoping for an expert to chime in. And Al is the Man!