hello, I've just finished a module of Transformer theory in trade school and was hoping to try some of it out. I plan on experimenting with winding my own toroidal power transformer. I require a 1:2 step up at 20V 150hz supply aiming at 150-300VA or so.
I have found a general ballpark equation to calculate primary turns for an EI type transformer which goes like this: is N = (E · 10^8)/ (4.44·f·A·B),
N= number of pri turns E= supply voltage f= frequency A= Cross sectional area of core (I think in square inches) B=max flux lines = rough figure of 60,000
Using a toroidal core with a CSA of 1sq" it gives me 50 turns for the primary.
Is this equaiton correct? Is the value of B ok for say a Mains 300VA toroidal core off the shelf? If anyone can help me answer these two questions, or point me somewhere that can I would be very greatfull.
Thankyou gavin.