Re: CCFL transformer

On 25-04-2024 16:52, legg wrote:

On Wed, 24 Apr 2024 01:57:36 +0200, Klaus Vestergaard Kragelund
<klauskvik@hotmail.com> wrote:
 

Hi
>
I need a low distributed capacitance winding transformer, for a HV
stepup function (3.5kV)
>
I am zeroing in on similar concept as CCFL transformers with
sectionalized bobbin.
>
For example:
>
https://www.coilcraft.com/en-us/products/transformers/power-transformers/ccfl-transformers/fl/
>
Possibly using Triple Insulated Wire to create some distance between the
individual turns.
>
Not many sells CCFLs these days.
>
Guess I will keep it alive....
>
Regards
>
Klaus

 Stress between turns is limited by v/n limit of core. It's layer
stress and section stress that you have to deal with.
That's what the multisection bobbin and pancake windings do.
 

Yes, but there will loss associated with the distributed capacitance between turns, that's why I am trying to reduce that one also

If the CCFL transformer will allow only 1600V, imagine the
precautions required for 3x that stress. I'm not sure you
can avoid vacuum impregnation / potting in anything 'small'.
 

I am actually working on an alternative idea, using 2 CCFL transformers, since as you write they are normally rated for 1600V. Incidentially, the 1600V is the start voltage, runs steady state at 600V.
The idea is to parallel 2 CCFL transformers primary winding, and series connect the secondary windings. Then connect the center tap to GND, that way I get -1600V and +1600V, total 3200V without violating the ratings of the transformer