Differences in structure between parafeed ad gapped OPTs

[dsavitsk]

Besides the fact that one is gapped, are there differences in the windings between parafeed and single feed transformers? Could you, in theory, restack the lams on a single feed transformer without a gaps and use it for parafeed duty, or vice versa?

[Miles Prower]

Originally posted by dsavitsk
Besides the fact that one is gapped, are there differences in the windings between parafeed and single feed transformers? Could you, in theory, restack the lams on a single feed transformer without a gaps and use it for parafeed duty, or vice versa?

I suppose you could, but not guarantee good performance. Changing the core to either open up or close a gap will cause the inductance to change enormously. This probably also alters the leakage inductance. As to what happens next, who knows? I wouldn't expect optimum performance either way.

[dsavitsk]

I wasn't going to to do this with good transformers, but thought playing with some cheapies might prove interesting.

On that note, does anyone have a decent reference for learning to design and wind transformers? I've found a number of online references that give the basics, but something that has a few more nuts and bolts on doing some of the actual math involved and balancing the tradeoffs would be great.

Additionally, does anyone know a source for small quantities of laminations?

[Tweeker]

Radiotron Designers Handbook 4 Chapter 5 is the public domain place to start. Somewhat opaque.

[Sheldon]

Originally posted by dsavitsk
On that note, does anyone have a decent reference for learning to design and wind transformers? I've found a number of online references that give the basics, but something that has a few more nuts and bolts on doing some of the actual math involved and balancing the tradeoffs would be great.

Additionally, does anyone know a source for small quantities of laminations?

Try this site, and this software: http://www.turneraudio.com.au/education+diy.html

http://www.dissident-audio.com/OPT_da/Page.html

I have some EI lams and bobbins sitting around. Had to order 1k sets of the lams. I'd also like to know if anyone sells small quants.

Sheldon

[Gluca]

Yes you can, and the transformer will work. It will not be the best parafeed tranny (that requires a smaller core so a proper and more efficient bobbin can be wound) but you will like it.

I found Turner's pages to be very educational and easy to read and learn.

Gianluca

[Yvesm]

Me think that if you use the same quantity of iron in an gaped SE OPT than the sum of what you need for the gaped choke plus the ungaped OPT, you should obtain very similar results.

Not to tell about the lo resonant pole introduced by the link cap.

My two pence.

Yves.

[Shoog]

My gut feeling is that you would be better served by using the gapped SE's in place of the expensive plate chokes. If you can get the right ratio then mains toroidals will make better parafeed outputs.

Shoog