hello I have this problem:

1. a 3300/250v, 50Hz,1pH transformer has a core of effective cross sectional area of
   13000m^2 and a low voltage winding of 80 turns.

Determine:
the number of turns on the high voltage windings
a, 250v / 3300v = 0.075 80 / 0.075 = 1066.6 turns


the maximum flux density of the core

b, 13000mm^2 / 1000,000 = 0.013m^2

3300/4.44*50*1066.6*0.013 = 1.072T

I was told this was wrong, though I cant find what is wrong. I have a guess that maybe the 0.013m^2 may be wrong but im not to sure. or the method for finding the high voltage windings

any help would be appreciated
thanks
simon

 

Your primary turns calculation is the source of the error.

 

+1 You have a rounding error.
Try solving by cross-multiplying.

 

ratio of voltages are 3300V/250V = 13.2:1

low voltage turns =80, so high voltage turns = 80x 13.2= 1056 turns

 

hey thanks a lot everyone for your help
I looked at a few formulas and found that answer

I used np = vp*ns/vs 3300*80/250 = 1056

I then got 1.0828T for maximum flux density by using

3300/4.44*50*1056*0.013


actually im not sure about that last part and cant figure it out properly.

13000mm^2, is that 0.013m^2, I don't know if that's right?

 

hello

could I get some help, with this, im not sure if im right

13000mm^2 is that 0.013m^2

I don't know if that's correct?

cheers

simon