Torodial Tranformer Calculation

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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/Transformatoren/O-Core/o-core.html
 
Posible source of info...

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
 
JanDH said:
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/Transformatoren/O-Core/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. :no:
http://www.trafoshop24.de
 
:att'n: :att'n: :att'n: :att'n: :att'n: :att'n: :att'n: :att'n:

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 :hot:

This thread is hereby reported to the moderator.

Magura
 
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.
 
peranders said:
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)
 
koolscooby said:
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 said:
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.


Does any of you guys have 4KV test equipment....im quite sure the answer is no, and in that case the trafo is to be considered dangerous, since you cant test it prior to use.

In the usa im sure kits are supplied, but also running only half the voltage, you already have twice the safety margin, plus the fact that all the isolation and so on is done correct by the manufacturer. In europe it is simply illeagal to sell something like that, since you cant have a CE approval for such.


Magura
 
This thread is slipping into usafe territory.

The thing that makes audio diy safer than dangerous sports is the mains isolation that we gain from employing a properly designed and certified component: A Mains Transformer.
I know that transformer kits are available "off the shelf", but these all (to my knowledge) have pre-wound and tested primaries. It's the primary where a diy'er could most easily get into trouble.

What you need to ask yourself is; is it worth exposing yourself and your family to danger for the sake of a few windings?
There are safety compliance issues that have not even been mentioned yet.

The more experienced members have a responsibility to the beginners, to demonstrate safe techniques. For every professional engineer member, there are probably several inexperienced members grasping for knowledge. What will we teach them?

I'm closing this thread for reasons of safety.:cop:
 
About turn..

I have been persuaded to re-open this thread.
Please can we confine the discussion to safe conduct. For me that really means dealing with secondarys. Of course the calculations for primaries and secondaries are practically the same, so on a purely theoretical level, the debate is open.
The concept of selling home-made transformers is however, off the menu:mad:

:cop:
 
Re: Re: Torodial Tranformer Calculation

Magura said:


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

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

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 :hot:

Magura

Yes, many of us have tried to help. I'm curious why someone with access to the knowledge you have has not tried to be helpful.

So, in the spirit of DIY audio... ...Please, can you post some information on how to test a transformer to european standards? I would like to know.

Also, is the transformer required to have been tested and certified, or just tested. After all, the CE is a certificaiton, not a test, right?

Is the certification sticker the requirement, or the testing itself?

How about every transformer built? Is every single one tested. (I would think they have to be, to ensure they are ALL safe). Or is the design tested, and the rest assumed to be safe?

If it's only the design, what sorts of things make a safe design?



dhaen said:
[B
The more experienced members have a responsibility to the beginners, to demonstrate safe techniques. For every professional engineer member, there are probably several inexperienced members grasping for knowledge. What will we teach them?

I'm closing this thread for reasons of safety.:cop: [/B]

What will we teach them?!? We will teach them what they ask. If we didn't, this board would be a useless waste of time and energy. Apparently, people who know the hazards are only willing to yell "DON'T", rather than help teach what the hazards are. I find this frustrating. How can we learn in this environment? What's the point of even being here?

As for the safety aspect of audio... ...Maybe we should shut down the entire board. With 30 volts considered lethal, all of my amps are condisdered deadly. Even the ones that I've purchased commercially. Maybe we should make it a law that you need an engineering degree to hook up speakers... ...More than 30 volts potential is availabile there too! Once we're at it, why not make it illegal to change your own light builb! There afterall, the line voltage is there too! Where do we stop?

The real issue is how to be reasonably safe. The phrase "safe and prudent" applies. Be aware of the risks, before starting any project. Just like all of the tube guys on this board. They deal with deadly voltages all of the time. When you start a tube project, you understand that from the beginning. You are more careful, and more safe, because of it. You assume your own liability, because you experiment. We are all aware of this, well before we start a project.



Magura said:
In europe it is simply illeagal to sell something like that, since you cant have a CE approval for such.

One final note. Magura's post here made me wonder.

All of you europeans building your own audio equipment, Do you have every single piece of your equipment certified? Is it illegal to build anything? Or is it just illegal to build it and sell it? Maybe you're all breaking the law, building your own amplifiers?

Please, if anyone knows, I'd like to hear what you know about the subject?

Thanks,
Dan


P.S. JanDH, sorry to be so far off of subject. I hope that if you were not aware of this, you are now. ;)
 
Re: Re: Re: Torodial Tranformer Calculation

dhaen said:
This thread is slipping into usafe territory.

The thing that makes audio diy safer than dangerous sports is the mains isolation that we gain from employing a properly designed and certified component: A Mains Transformer.
I know that transformer kits are available "off the shelf", but these all (to my knowledge) have pre-wound and tested primaries. It's the primary where a diy'er could most easily get into trouble.

What you need to ask yourself is; is it worth exposing yourself and your family to danger for the sake of a few windings?


A very good point...very good point.
I do have the nessecery means and knowledge to make a trafo, but considering the dangers of it, i stay clear of it.


dkemppai said:


<Yes, many of us have tried to help. I'm curious why someone with access to the knowledge you have has not tried to be helpful.

Because if people want to hurt themselves and their families...i dont want to play a part.

<So, in the spirit of DIY audio... ...Please, can you post some information on how to test a transformer to european standards? I would like to know.


As i remember it, it have to be tested to 4KV on all windings, its got to have a temperature rating and a safety factor of (not sure) 8 x overload for 10mSec.


<Also, is the transformer required to have been tested and certified, or just tested. After all, the CE is a certificaiton, not a test, right?

Tested and certified.


<Is the certification sticker the requirement, or the testing itself?

Both

<How about every transformer built? Is every single one tested. (I would think they have to be, to ensure they are ALL safe). Or is the design tested, and the rest assumed to be safe?


All are tested to 4KV

<If it's only the design, what sorts of things make a safe design?


The right dimensions, the right type of isolation, the right typr of wire isolation, the right type and size of core...the list is long.


< What will we teach them?!? We will teach them what they ask. If we didn't, this board would be a useless waste of time and energy. Apparently, people who know the hazards are only willing to yell "DON'T", rather than help teach what the hazards are. I find this frustrating. How can we learn in this environment? What's the point of even being here?


Read this statement once more...and think if you really mean this. There is loads of help and hints to get here, but this is something i know for a fact is waaaaay out of 99% of the members range.... and if anybody here actually are able to do this in a safe way, they sure dont need any help.



<The real issue is how to be reasonably safe. The phrase "safe and prudent" applies. Be aware of the risks, before starting any project. Just like all of the tube guys on this board. They deal with deadly voltages all of the time. When you start a tube project, you understand that from the beginning. You are more careful, and more safe, because of it. You assume your own liability, because you experiment. We are all aware of this, well before we start a project.

The subtle difference between a high voltage tube design and a homemade trafo is that the tube design is made up to specifications to begin with, or you sure will find out. With a bad trafo....it may all of a sudden make the whole amp carry 200mains or worse.



<One final note. Magura's post here made me wonder.

<All of you europeans building your own audio equipment, Do you have every single piece of your equipment certified? Is it illegal to build anything? Or is it just illegal to build it and sell it? Maybe you're all breaking the law, building your own amplifiers?





You cant sell anything that isnt CE certified....and there is a reason for that !!!!

Dont get me all wrong, all im saying is that this is not to be made at home for obvious reasons. I know that trafos are made at home all the time, mostly i guess with no problems, the problem is that if something happens...its most likely real bad. Now since we know that it takes a little more than a roll of magnet wire and a core....then be prudent and have one made by a company thats got the right stuff for making one. The price is almost the same in the end anyway.

Cheer up Dan....loads of good and fun stuff to DIY...just not torriodal trafos :)

Magura
 
Well Peter you know what i mean ;)

Everything sure is possible.....including electricuting the neighbours that came over for a visit :(

I am aware of the fact that im fairly new on this board, but you will learn that i stick to the everything is possible satement pretty much....i just dont like people to do something they havnt done the footwork to be able to do in a safe manner. As i wrote in the previous post, "anybody able to wind a torriod safely, sure dont need my advice".

I like to take things to the limit, just like many of you (working on DIY 200W thick film resistors, wirewound 200W copper clad resistors, cast boxes....(in the name of a SOZ)), but i like to play it safe :)

MAgura
 
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