My input voltage is 120 Vac at 400 Hz, and my desired output voltage is 26 volts with a load of 85 ohms, and a power rating of 8 VA.

Using a Magnetic Metals 25EI core with a 0.5" stack height, I calculate the primary turns should be about 322 with B = 13 k Gauss. I plan to use 30 AWG magnet wire for both primary and secondary.

Does anyone know how I can calculate the secondary turns to meet the 26 volt full load spec? (No spec for No load output voltage is given - I know it would be 70 turns if it was 26 Volts out at no load)

If so, could you show me how, including the formulas?

Also, I would like to be able to calculate the temperature rise for this design. If someone knows how, please help.

Thanks