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Practical Transformer Winding




 
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k4kyv
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Don
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« on: October 18, 2011, 10:20:54 AM »

Even if you don't plan to wind or re-wind a transformer, here is some good information on how transformers are constructed, with plenty of photos. It doesn't cover the subject 100%, but is informative, especially for those who have never taken a transformer apart.

http://ludens.cl/Electron/trafos/trafos.html

He also has a link to another article on coils and transformers, but I don't think he is 100% correct on everything, particularly the section on DC chokes. He doesn't mention anything about gapping the core, and I question his statement that "... DC is simply a very, very low frequency... :-)" (like infinitely low, maybe?)

http://ludens.cl/Electron/Magnet.html





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Don, K4KYV                                       AMI#5
Licensed since 1959 and not happy to be back on AM...    Never got off AM in the first place.

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K5UJ
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« Reply #1 on: October 18, 2011, 01:35:35 PM »

Thanks don I did not know about that page.

Also if you scroll down here:

http://en.wikipedia.org/wiki/Transformer

There are diagrams on the right that show the way the coils are wound for the primary and secondary on an open EI core shell transformer.  Back last spring I realized that for me, transformers were another one of those black box type things i.e. I didn't really understand exactly how the coils were wound.  I found the wikipedia diagram under Windings helpful for a beginning understanding.

Rob
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KM1H
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« Reply #2 on: October 18, 2011, 07:57:22 PM »

I wish I had all that info when I started rewinding in the late 50's! Too much trial and error and I got away from it.

Id like to do a big mod transformer but that would likely be a couple of stacked toroids. Too much black magic in the old methods.
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Patrick J. / KD5OEI
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« Reply #3 on: October 18, 2011, 08:12:27 PM »

It is the need for tooling, pretty much specially made up for the bobbin at hand, and the neatly layered wire when more than a few layers are needed, that has prevented me from trying transformers with more than a couple hundred turns.

It is very satisfying to wind one's own transformers, even if just small filament units. I never tried toroids due to having to figure out how to pass the entire spool of wire through, all were small EI cores where I saved the bobbins. Only three fil. units and one 140V unit for RTTY magnet power so far, I guess I am lazy and that is not a very good score for 40 years of experiments!

I'd like to see a home made toroidal mod transformer, that would be very cool! Do it!
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Radio Candelstein - Flagship Station of the NRK Radio Network.
The Slab Bacon
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« Reply #4 on: October 19, 2011, 09:26:30 AM »

Transformer winding may be a P.I.T.A., but the most miserable thing I EVER did was to rewind a magneto coil! ! ! ! ! ! ! ! ! (myself and a friend did 3 of them). They were for an American Bosch magneto for a 1 1/2 Hp early 1920s model Z Fairbanks-Morse gas engine. This was before they started making their own magnetos.

(apparently all of them failed from moisture)

Myself and a friend (who was deeply religious and didn't cuss) must have invented at least a dozen NEW cusswords winding those things. That hair fine wire is miserable to work with! But that was 35 years ago and mine is still working fine.
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WZ1M
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« Reply #5 on: October 19, 2011, 09:46:57 AM »

Talk about "MISERABLE", try winding 30,000 turns of #38 on a bobbin. Those interstage transformers are a real PITA. After you have the winding completed, now you have to attach leads to the tiny wire. Many a time it has broken off. and you have to start all over.
Regards,
Gary  Angry
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The Slab Bacon
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« Reply #6 on: October 19, 2011, 11:00:38 AM »

Talk about "MISERABLE", try winding 30,000 turns of #38 on a bobbin. Those interstage transformers are a real PITA. After you have the winding completed, now you have to attach leads to the tiny wire. Many a time it has broken off. and you have to start all over.
Regards,
Gary  Angry

Gary,
       at this point in my life, I dont think I would have the patience for that fine wire anymore. I would probably give it "flying lessons". (or send it to you) 30,000 turns sounds to me like chucking the bobbin in a lathe with the lathe backgeared.
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K9PNP
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« Reply #7 on: October 19, 2011, 01:04:35 PM »

He doesn't mention anything about gapping the core, and I question his statement that "... DC is simply a very, very low frequency... :-)" (like infinitely low, maybe?)

I guess he's one of those guys that looks at it as "approaching zero tangently".

Good post, Don.  Didn't realize how much I had forgotten or didn't know about the subject.  Thanks.
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73,  Mitch

Since 1958. There still is nothing like tubes to keep your coffee warm in the shack.

Vulcan Theory of Troubleshooting:  Once you have eliminated the impossible, whatever remains, however improbable, must be the truth.
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« Reply #8 on: October 19, 2011, 02:31:44 PM »

Hey slab:
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