power transformer design help...

Hi,

I'm trying to design a power transformer that has Lprim~=86mH and Lsek~=1.62H values. I use potcore ferroxcube 3c91.

I tried to measure the inductance of secondary winding (primary winding is not placed yet) by applying DC voltage for a while and then measuring di,dt and DC voltage through inductor (VL) so (VL)*dt/di in the linear region gives the inductance OK. but during the measurement of inductance I realized that the saturation current of the secondary winding is too low (at about 20mA).
I used AWG32 wire and about 450 turns. do you think there is a problem? is it possible to saturate current levels like this or I have a wrong angle of view? or during the winding should I do smt like putting insulator between each layer (thats not possible because of crowded potcore) please somebody give me a the right angle of view!

During the design I suffered lack of knowledge! if somebody suggest an application note (not too complicated) that covers transformer design will be more than appreciated.

thanks everybody

That saturation current doesn't sound too unrealistic. Depends on the core area though. What size is the core?

If saturation is a problem, then your only option is likely to either use a larger core or use an air gap and add more turns.