NNOMMER

${?}^{719004070}$

$(8080074)$

$(4)$

$[30]$

QUESTION $4$: TRANSFORMERS

O$20$Q$1$E$2419004070$

$4\mathrm{.}1$ Show using a two single$-$phase configuration, how a star$-$delta transformer is connected for a three$-$phase, four$-$wire system.

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$4\mathrm{.}2$ A single$-$phase $\frac{222}{2220}V,50Hz$ transformer has a net area of $100c{m}^2$ and $200$ turns on the primary windings.

Calculate the maximum flux density in Tesla and the number of turns in the secondary windings.

$(4)$

$[10]$