Question

What is the RMS value of the inducted EMF/turn in a transformer?

1. \( \frac{{{4.44f}}}{{{\phi _m}}} V\)
2. 4.44 f ϕm V
3. 1.11 f ϕm V 
4. 4 f ϕm V

Answer 1

Correct Answer - Option 2 : 4.44 f ϕm V

Induced emf of the transformer can be determined as 

E1 = 4.44 ϕ f N1

E2 = 4.44 ϕ f N2

Where,

E1 = RMS value of primary side induced emf

E2 = RMS value of secondary side induced emf

ϕ = flux

N1= Number of turns in the primary side

N2 = Number of turns in the secondary side

f = supply frequency

∴ RMS value of the inducted EMF/turn in a transformer is given by

\(\frac{{{E_1}}}{{{N_1}}} = \frac{{{E_2}}}{{{N_2}}} = 4.44f{\phi _m}\)

This is called the emf equation of transformer, which shows, emf/number of turns is the same for both primary and secondary winding.