Question

A power transformer has \[\;50\;\]turns for primary and \[300\] turns for
secondary. What is the turn ratio? How much is secondary voltage with primary voltage of
\[230\;V\]?

Answer 1

Hint: Voltage in primary is directly proportional to the number of turns in the primary and voltage in the secondary is directly proportional to the number of turns in the secondary because when the magnetic lines of flux flow around the core, they pass through the turns of the primary winding, causing a voltage to be induced into the primary coil of the transformer. And when the magnetic lines of flux flow around the core, they pass through the turns of the secondary winding.

Step by step answer:Turns for primary = ${N_1} = 50$
Turns for secondary = ${N_2} = 300$
The ratio of the number of turns in the primary winding to the number of turns in the secondary winding is called turn ratio
Turn ratio = $\dfrac{{{N_2}}}{{{N_1}}}$ = $\dfrac{{300}}{{50}} = 6$
When the magnetic lines of flux flow around the core, they pass through the turns of the primary winding, causing a voltage to be induced into the primary coil of the transformer.
And when the magnetic lines of flux flow around the core, they pass through the turns of the secondary winding, causing a voltage to be induced into the secondary coil of the transformer.
Since voltage in primary is directly proportional to the number of turns in the primary and voltage in the secondary is directly proportional to the number of turns in the secondary,
\[\dfrac{{{V_1}}}{{{V_{_2}}}} = \dfrac{{{N_1}}}{{{N_2}}}\]
Where, ${V_1}$= voltage in the primary
${V_2}$ = voltage in the secondary
Voltage in the secondary= ${V_2}$ = \[\dfrac{{{V_1}}}{{{N_1}}} \times {N_2}\]
Hence ${V_2}$ = \[\dfrac{{230}}{{50}} \times 300\]
${V_2}$ = 1380V

Note: The amount of voltage induced in the transformer when current flows through it will be determined by faraday’s law. As there are two coils in the transformer so care must be taken that which term is founded out from which circuit.