RE: help needed to build transformer

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com> 

 >You will need about 1500 turns of 18 AWG on the primary and 15000 turns of
 >22 AWG on the secondary.

at 100kHz?!?!?! surely not.. you'll need a ferrite core to start with, and
probably about 20 primary turns and 200 secondary, depending on the size of
the core. You will have serious trouble with parasitic inductance and
capacitance.

One way round this is interleaving- you might make 5 layers of 40 secondary
turns, interleaved with 4 layers of 5 primary turns (preferably using copper
strap instead of round wire) This can cause trouble with insulation, though:
you will need thick insulation between layers, and maybe vacuum impregnation
or operation under oil.

You might want to read these articles that deal with output transformers for
SSTC magnifiers (a similar application to yours)

http://members.aol-dot-com/alansharp03/page6.htm
http://members.aol-dot-com/alansharp03/xformer.htm

Even with interleaving, the leakage inductance might be too high to operate
at 450kHz, and it might prove easier to redesign your power supply to
resonate with the leakage inductance, as in Marco DeNicolai's "Thor" power
supply.

Steve C.