Torodial Tranformer Calculation

[JanDH]

I would like to wind some o-cores. Can anyone show me a site where I can find info regarding number of windings, wire thickness and optimize the transformer for audio applications. There should be somewhere an Excel spreadsheet where one can input primary and secundary voltages and power requirements. Some tips on how to actually wind and build.

I would like to have somethin like this:

http://www.feickert.de/Transformator...re/o-core.html

[dkemppai]

Hi,

the "o" cores you refer to are usually call toroid cores...

These guys have some good info. They usually cover good solid design...
http://www.mag-inc.com/library.asp

Look for the tape wound cores section. (Tape wound referes to the core itself, not the windings)

Here's the link:
http://www.mag-inc.com/pdf/twc-s1.pdf

The page will probably have the information you will need. Once you understand the concepts, designing a transformer isn't really all that difficult.

Good Luck!
-Dan

[peranders]

Originally posted by JanDH
I would like to wind some o-cores. Can anyone show me a site where I can find info regarding number of windings, wire thickness and optimize the transformer for audio applications. There should be somewhere an Excel spreadsheet where one can input primary and secundary voltages and power requirements. Some tips on how to actually wind and build.

I would like to have somethin like this:

http://www.feickert.de/Transformator...re/o-core.html

If you don't have very special requirements I advice you not to make your own transformer just because this is a safety issue. Since you live in Europe the transformer must be safe at 230 VAC andbe able take 4000 volts between primary and secondary windings.
http://www.trafoshop24.de

[Jocko Homo]

Make sure that the windings are evenly distributed over the entire core.

Jocko

[jackinnj]

http://www.tech-diy.com/smps_xfmr.xls

[Magura]

I like the spirit.....but this is stupidity.

I like to make all kinds of stuff myself as well....i honestly hate the fact that i cant make mosfets....but thats life.

To wind your own trafo is dangerous.....very dangerous....potentially lethal.

Like most people on this forum ive had an accident or two with mains power, and that hurts (under the wrong circumstances...lethal as well), but a trafo not made 120% up to CE specifications (trust me, you cant do that, it takes the right machinery) is a very unlucky thing to have around, not to mention the risk to blow your entire stereo.

As peranders mentioned, even testing the trafo at 4KV is quite risky....believe me, i grew up with an electromechanic for a dad.

I cant believe so many people have been helpfull to this project, it cant be true that only peranders is equipped with a brain. Not a nice thing to say..i know, but this is shocking

This thread is hereby reported to the moderator.

Magura

[koolscooby]

sicne when have members been restricted on what we discuss and what activities we partake? as far as i nkow, never hehe... people make their own transformers here all the time... just wondering why Magura is reporting this to moderators when people arej ust trying to expand their knowledge....

[Brian Donaldson]

Settle down Magura, Don't be a puss.

Toriod.com in the us sells kit transformers with the primary already wound and data to roll your own secondary. Look around on thier site, you may get some ideas.

[peranders]

230 V primary winding takes approx. 230 /0.3 turns (0.3 V per turn) = 700-800 turns nice and even winded. How many meter do you need? Many! Hopeless project!

If you start with which power you need volt and VA, I'm sure you can find a new or used toroid suitable for your needs.

State your requirements and we can help you telling what you need.

[elizard]

Originally posted by peranders
230 V primary winding takes approx. 230 /0.3 turns (0.3 V per turn) = 700-800 turns nice and even winded. How many meter do you need? Many! Hopeless project!

If you start with which power you need volt and VA, I'm sure you can find a new or used toroid suitable for your needs.

State your requirements and we can help you telling what you need.

Hopeless project???
lets say 800 turns .. the diameter of the core (cross-section this is btw) would be what, 2cm tops?
so, that makes the circumference 12.566cm
so you end up with just over 100m of wire .. 100m of magnet wire is a very manageable chunk (once you start winding some HUGE 3 phase electrical motors, you'll understand)

I'm not sure why people are so uptight about winding transformers. Not sure if its the toroids, or transformers in general, because i've heard of many people winding EI's (and I can see how its fairly easy to wind an EI). Toroid, although more difficult to wind, i'm sure can't be THAT hard.
I mean, people deal with voltages and currents in amps that would kill a horse regularly without much in terms of worries (apart from common sense, and some safety precautions)

Although, as said, if its a standard secondary voltage, you will probably be MUCH better off to buy a new one. In canada you can get a 1000VA toroid for $140, and a 1500VA one for $200 from plitron ..
so unless you need several 1000VA transformers, or you need transformers that have a hundred and one different secondary voltages, its not cost effective to build JUST one
(although one can build multiple then sell them)