Question

The maximum flux density in the core of a 300/3000 V, 50 Hz single phase transformer. If the EMF per turn is 10 V, determine primary and secondary turns, respectively.
1. 30, 300
2. 3, 30
3. 300, 300
4. 15, 30

Answer 1

Correct Answer - Option 1 : 30, 300

Concept :

Transformation Ratio :

• Transformation ratio is defined as the ratio of secondary voltage to the primary voltage.
• It can also be defined as the ratio of the number of turns in the secondary winding to the number of turns in the primary winding.
• It can also be related to the current flowing in the primary winding to the current flow in the secondary winding.
• It is represented by the letter ‘K’

K = (E1 / E2) = (N1 / N2) = (I1 / I2)

Calculations :

Given ELV = 300 V, EHV = 3000

Emf per turn = 10 V

ELV = NLV × emf per turn

∴ NLV = ELV / emf per turn

Similarly NHV = EHV / emf per turn

NLV = 300 / 10 = 30

NHV = 3000 / 10 = 300