HF Trafo Core Selection

[kall]

i really hope u guys and girls have a solution to my problem....i hope its okey.

i want to build a transformer but i cant find a suitable core for my calculated values....

here is some data:
n: 20/1
P: 2.5kW
f: 100kHz
I1rms ~ 7A
I2rms: ~ 115A

the thing is, i want to use a UU, UI core, and with U93 from ferroxcube i get a flux at 10mT .... im basically not using the core at all

if i go down in size, the windings wont fit because i need atleast n1 to be 40 turns due to the large turnsratio of 20 to 1 ....

am i thinking wrong??, i think u experienced builders have a solution to this....

[Sch3mat1c]

Who cares about current, what's voltage? Flux is Wb == V.s, nothing to do with amps.

Tim

[sawreyrw]

Tim,

The transformer current is important, because that sets the wire size. Yes, the number of turns depends on the applied volt seconds.

kall,

I can't remember the exact formula for the number of turns, but it is given by E=N*d(B*Ac)/dt or N=E/(d(B*A)/dt).

Rick

[kall]

well, N1 = (Vd*D*Ts )/(Ae*B)

Vd = 400V