Question

A power transmission line feeds input power at 2300v to a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 v by the transformer. If the currents in the primary of the transformer is 5a and its efficiency is 90%, the output current would be

Answer 1

n% = \frac{P_{out}}{P_{in}}\times 100=\frac{V_{s}\, {i}'_{s}}{V_{P}\, {i}'P}\times 100

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\frac{v_{s}}{v_{p}}=\frac{n_{s}}{n_{p}}      (for ideal )

 

for non ideal \frac{p_{s}}{p_{p}}=0.9

\frac{I_{s}V_{s}}{V_{p}I_{p}}=0.9

I_{s}=\frac{0.9*2300*5}{230}

I_{s}=45A