winding yer own transformers, somewhat OT.

[Mark Amundson]

> >Ok, I have been dabbling with winding hi voltage
> transformers for projects like jacobs ladders and such 
> >
> > I recently bought a pre-made ferrite E-core complete with
> a hollow spindle and clips..nifty... 
> 
> I haven't got any experience with 'Jacobs ladders' and
> stuff, but as a SMPS designer perhaps I can say something
> usefull here.... The biggest difference between these two materials is the
> operating frequency range...

> In high voltage apps, the way of winding the transformer is
> very important  Daniel...

I want to add to Daniels response by recommending a check of B-H curves
for the cores you are using. Frequency and power capability is a concern
here. A grasp of magnetics design equations should be mandatory before
picking cores. Ferrite will work, but it is considered overkill for
frequency applications. Also the effective core gap and reluctance
numbers are very different from E-I to Ferrite.

High voltage winding are non trivial here also. You are going to have to
have a good winding stategy and know the dielectric breakdown strengths
of the magnet wire insulation, bobbin and layer seperator material
(usually yellow Kapton Tape). Arcing and corona formation get be an
issue on closely wound and small transformers in kilo-volt applications.

Mark Amundson,