You may well have the ability or just learn on the job and good luck to you,
BUT, since the transformer is the main barrier to mains electricity supply
this is the major safety element. You can buy or hire instruments to test
the final product for inter-winding breakdown and breakdown to core and if
you are very careful with your windings at the edge of the bobbin you might
be able to get the proper creepage and clearance distances required. If you
use a split bobbin design this is much easier.
You will also need to get the winding tension just right so as to stretch
the wire a little (that makes in thinner and stiffer and carry less current)
and you need to get the right packing density otherwise you will run out of
winding space and the transformer will not perform properly, (magnetising
current etc).
When you have made your transformer you then need to do temperature rise
tests: apply the absolute maximum load (not easy to know in a
rectifier/capacitor/resistor load including on-off ratio) and measure the
temperature rise with 115% high mains voltage. The rise must be within UL
limits for the wire, insulation and bobbin you are using. You need to leave
it on load until the temperature stabilises.
For me one of the best things to happen to transformers in the last 20 or so
years is the advent of the PTC resistor in series with the supply winding.
This should be embedded into/onto the primary winding so it picks up local
heat but also generates its own. It will trip to high resistance on
overload of either or both temperature and current. It's tricky to get the
right value but makes for a very much better design.
When you've made a few prototypes and got everything just right, you then
you need to put your neck on the line, your hand on your heart and say this
product is safe.
You will be on very tricky ground if you allow anyone else to operate that
equipment other than yourself.
I would not wind my own mains transformer, I know too much and too little.
David
G3UNA
> Where can an individual purchase core material, paper, wire, etc? We may
> need to get serious about winding our own...
> Wonder if there is a distributor who will sell Hypersil C cores to hams.
> I would love to give it a try -- but can seem to locate anything on the
> Internet.
>
>
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