Rewinding Toroidals for Dummys?

[ken.berg]

I've often seen mention of lowering the voltage of a toroidal transformer by removing secondary windings.

What I have not seen is any indication of appropriate materials to use when re-wrapping the transformer or appropriate methods to provide strain relief to the flying leads.

Now, it is possible that all will be apparent once I cut the thing open, but I remember thinking that same thing about my father's Movado watch when I was seven...

I've googled, but cannot find any photos of the process, or specific materials guidance - can anyone proved same, or does anyone know of good web reference that I missed?

[Stuart Easson]

Ken,

My guidance has always come from the transformer I am reworking. Most are wrapped in some sort of plastic tape, the last couple being kapton as far as I could tell. I always figured the best plan was simply to put it back when I was done. So far I haven't ever seen the stuff for sale, but then the sort of shops I frequent would be more likely to have complete transformers than the components to make them.

Strain relief is trickier, last transformer I worked on didn't have any except for the coloured sleeves over the enamelled wire emerging from the windings. On another piece I saw a fibrous cardboard material used to wrap the soldered connections between the various secondaries and the output wires and then got buried under the final layers of wire.

For me strain relief is a lesser issue, I try not to put any physical strain on the leads anyway, I leave them longish (~4")then terminate and connect them at something solidly mounted.

Stuart

[Magura]

Originally posted by ken.berg
I've often seen mention of lowering the voltage of a toroidal transformer by removing secondary windings.

What I have not seen is any indication of appropriate materials to use when re-wrapping the transformer or appropriate methods to provide strain relief to the flying leads.

Transformers are usually wrapped in mylar film.....not easily found in the local hardware store.

Magura