Iron Core Transformer Formula

[AndrewT]

paper will be a source of fuel for burning.
Similarly most varnishes will be fuel for burning.
Adhesives will be a fuel for burning.

Asbestos and glasswool and rockwool and mica have a very high resistance to burning. (I am not suggesting you use any of these, just showing what the difference is when thinking of Fuel).

You must choose carefully to avoid combustion during/after overheating.

BTW,
combustion (or charring) results in carbon residue that is likely to conduct electricity.

Hi temperature Mylar tape (without adhesive) is often used, but difficult to source.

[iko]

Have a look at this page, it has some good info on winding your own transformers, including info about insulating material.

output-trans-winding.html

[iko]

If you're looking for a cheap alternative insulating material you might want to consider the ptfe (teflon) plumbing tape. Of course, proper insulating paper like Nomex is what you should use, but it's very expensive.

[jcx]

NO!

teflon plumbers tape will "creep", flow under the slightest stress, thinning the insulation to nothing over time - it is NOT a suitable electrical insulator

[iko]

I agree that only proper insulating material should be used.

But I wonder why you say that the teflon tape would thin over time; even if layered thick enough? What kind of stresses would a transformer sustain in use? Just curious what you have in mind, that's all.

[jcx]

the pressure inside a multilayer winding can be huge - each additional layer of wire's winding tension adds to the pressure

then there is also extreme stress concentration when wires cross at angles instead of laying in the layers evenly

teflon in particular embodies the concept of "plastic" to a unintuitive extreme - the molecules are so slippery they will slide past each other on a very long time scale - look up "creep" in plastics

our intuition is more experienced with stuff like mylar that "work hardens" as stretching orients the molecules along the stress axis and they stick together enough to become more resistant to further deformation

teflon basicaly creeps forever

[iko]

Well then, forget considering plumber's teflon tape for use in transformers. Use Nomex.

[JOHN BALI]

ok, I wil to try find nomex

but if I can't find maybe I will use plumber's teflon tape I have it a lot
I don't know if anyone has really use it before on trafo making, maybe I'll be the one
the point is I must use anything that can resist fire & thin enough to put in

Thanks to all reply

[Tony]

i use all of these in my transformer builds....

i use "fishpaper", kraft paper, and many other kinds of papers, i never had a traffo burn out on me......

[JOHN BALI]

Originally Posted by Tony

i use all of these in my transformer builds....

i use "fishpaper", kraft paper, and many other kinds of papers, i never had a traffo burn out on me......

Thanks Tony

I find this paper

Maybe it is can be used...
my mother often use it in the kitchen to make some cake
btw, now is mother's day here in my country
Happy mother's day for my mom
wish you all the best

Then if we make trafo that run cool (below 1T)
why we need so expensive insulator material?
But if we run the trafo more than 1T
that good insulating material must be used

So if I go 0.8-0.9T & I use this paper I guess it just okay
but if not okay please tell me...
The trafo that I made earlier even not using inter layer insulator