Question

With the increase in supply frequency of transformer, there is _____ in rating.
1. Decrease
2. Increase
3. No change
4. None of these

Answer 1

Correct Answer - Option 2 : Increase

Concept:

The voltage of primary of the transformer is,

\(V_1 = 4.44\times f\times \phi_m\times N_1\)

The voltage of secondary of the transformer is,

\(V_2 = 4.44\times f\times \phi_m\times N_2\)

Where,

N₁ is the number of turns of the primary 

N₂ is the number of turns of secondary

f is the supply frequency

ϕm is the flux

As we know that, 

kVA rating is the multiplication of voltage and current.

kVA = V × I 

As we know the kVA  ∝ V

And V ∝ f

As the increase in frequency, the kVA rating is also increasing.

 

The frequency is inversely proportional to the size of the transformer.

\(f \propto \frac{1}{Size}\)

As the increase in the frequency then the size of the transformer decreases and vice-versa.