Transformer winding insulation

"sbrehler"

But folk often wind their own RF coils and small inductors for loudspeaker x-overs.

..... Phil

You want 'Magnet Wire'

Classic insulations were Formvar and Heavy Formvar, which are very tough varnishes... so tough they are hard to strip. You can also use nylon or polyurethane insulated magnet wire, which self-strip with a very hot soldering iron but are not as tough. All will wind nicely without much danger of shorting. The Formvar is better for high-temperature use, and HF for high temp and/or high voltage.

I've hand-wound a lot of small transformers, mostly toroids and pot cores, with all sorts of wire as noted, and don't recall any winding shorts. Go for it.

John

"sbrehler"

But folk often wind their own RF coils and small inductors for loudspeaker x-overs.

..... Phil

Ah ha! Magnet wire. I get all kinds of hits on that. Once again, thank you both for your help.

Scott

Go to powerintegrations.com and download all thie app notes. If you don'y understand after that, you're in the wrong business.

Also look at TEW (triple insulated wire) Google it.

Graaam

Thankfully these aren't safety products.

Wht didn't you mention bobbins etc ?

Graham

AND an IEC standard.

Graham

Are you a MANIAC ?

John, my respect for you has dropped below the floor with such idiotic comments.

Graham

Yes, it acts as an insulator but you must ALSO know about MARGINS (these are seperations between primary and secondary essentially).

Forget that, it blows up, and you are in JAIL and your house is repossesed.

Graham

comments.

The fact that the DD doesn't like him raises the respect from anyone with a brain.

Must be hell to live in a communist nanny state, like yours.

comments.

He's an audio amateur disco sound guy. No wonder his windings short. Or his shorts are all wound up. Whatever.

John

comments.

Austin Powers with a $6 BSR plastic turntable.

For experiments with low voltage, low current stuff, you can sometimes scrounge the wire from old transformers or from old TV yoke coils.

Ed

People do wind their own. If you wind a lot of them you build a winding lathe that spins the bobbins for you and a turns counter that keeps track - and it is a whole lot less tedious.

I suspect people are just too lazy to wind their own - and laminations are a specialty item so you end up salvaging core material from other transformers.

Enamel magnet wire is very resistant to nicks as a rule. Sometimes a kink, pulled tight, will cause it to flake off.

I worked for a PS manufacturer in the 70's. It was SOP on some tight transformers to insulate layers with mylar tape, with an over wrap of heavy paper tape. To get them to fit the laminations sometimes we would hit them with a hammer to get the coils to fit (we protected the surface with a block of nylon then just gave it a whack to make the layers lay down enough to squeeze it in)

Its often easier to wind a big transformer than a small one for line frequencies - big easy to see wire that doesn't break easily, and fewer turns per volt because the iron is large.

I wound an induction coil with thirteen miles of #32 gauge wire in the secondary - four bobbins with paper between layers. Took me a week but I did paint varnish on each layer before laying down another layer. ~40 layers per bobbin. Each layer took about 15 minutes with a motorized winder.

Winding transformers is fun in my opinion.

When the rotor on my motorcycle alternator shorted I wound a new one and saved ~$300

x-former

own?

He's in the US, so he doesn't need any 'Idiotic European Crap'