Determine the regulation of a transformer in which ohmic loss is 1% of the output and the reactance drop is 5% of the voltage when power factor is unity.

The correct answer is option 1): 1%

Concept:

Voltage regulation is the change in secondary terminal voltage from no load to full load at a specific power factor of load and the change is expressed in percentage.

E₂ = no-load secondary voltage

V₂ = full load secondary voltage

Voltage regulation for the transformer is given by the ratio of change in secondary terminal voltage from no load to full load to no load secondary voltage.

Voltage regulation  \(= \frac{{{E_2} - {V_2}}}{{{E_2}}}\)

Regulation = %R cos ϕ ± %X sin ϕ

Calculation:

Ohmic loss (%R) = 1%

Reactance drop (%X) = 5%

Power factor = cos ϕ = 1

sin  ϕ = 0

Regulation = %R cos ϕ ± %X sin ϕ

= 1(1) + 0

= 1