Transformer turns ratio

hi all
I need some help with a transformer problem ,getting problem to determine the turns ratio
my Vs=150 and Vp=225
also Ip=5 and Is=7.5 I divided 225/150 and got 1.5 however the actual turns ratio the book states is 3:2 how do I proceed in working this to get 3:2 I tried Np/Ns=Vs/Vp but still not getting true

And 3/2 is?

Your approcing the problem wrong:

225/150; you need to use the least common divisor.

because it ends in 5, numerator and denominator are divisible by 5 any you get 45/30
So continue.

Your answer is 1.5:1 which is 3/2; it's also 15/10 or 3/2 or 3:2

Take the ----- as divide and 10/10 to be 1.

Another way is to factor 225 and 150 and cancel like terms in numerator and denominator.
(5*45)/(5*30)
and keep continuing.

Thanks alot, I thought I had to use the formula...

Hi,

You do use a formula, but then you try to get rid of the fractional part and express both numbers as whole numbers. For your example you get:
1.5/1

and if you multiply top and bottom by 2, you get:
3/2

and that is the same as 3:2 so you see how easy this is.

If we had a different transformer and we got:
1.3333/1

then we would multiply top and bottom by 3 to get:
4/3

which is the same as 4:3, and notice this time we rounded a little.

When using the formula Vp/Vs for your problem we get a single number:
Vp/Vs=225/150=1.5

but as im sure you can see we can write this as:
1.5/1

and then we just see what it takes to get that top number to be a whole number through multiplication. Since if we multiply 1.5 times 2, we use the factor '2' on both the top and the bottom to arrive at the 3/2 and then we may just write it as 3:2 instead.

Since this is an ideal power xformer, Vp*Ip=Vs*Is, so Vp:Vs and Ip:Is and Np:Ns is related by the same proportionality constant.

It's just that a typical "ratio" is the ratio of 2 integers. A "math" thing.