Page 542 - Basic Electrical Engineering

E = N ϕ ω
m
m

or,

E = N ϕ 2πϕ
m
m

We know for a sinusoidal voltage, the RMS value is times its maximum

value. If, E is the RMS value of the induced EMF, then

Primary winding has N turns. The induced EMF in the primary winding E 1
1
is

E = 4.44 ϕ f N V (6.3)
1
m
1
Since the same flux producing E also links the secondary winding having N 2
1
number of turns, the induced EMF in the secondary winding, E is
2

E = 4.44 ϕ f N V (6.4)
2
2
m
Dividing eq. (6.3) by eq. (6.4),

K is called the ratio of voltage transformation. For a step-up transformer, N 2

> N , and hence, the value of K is more than 1. For a step-down transformer,
1