i have desined a transformer for follwing parameters 21v , 200mA 12v, 50mA 27v, 80mA for this i m using bobbinn and core EF25 , 10 PIn horzontal former i already checked guage and number of turns . guage is adequate for current right now i don't have data for guage and turns so post it tommorow. and ambient temp. is around 25'c (room temp). transformer works properly without heating if i test my supply outside my instrument housing but gets heated when i put it in housing.