$4-13.$ A $25-$MVA, $12\mathrm{.}2-$kV$,0\mathrm{.}9-$PF$-$lagging, three$-$phase, two$-$pole, Y$-$connected, $60-$Hz synchronous generator was tested by the open$-$circuit test, and its air$-$gap voltage was extrapolated with the following results: Open$-$circuit test Field current, A $320365380475570$ Line voltage, kV $13\mathrm{.}013\mathrm{.}814\mathrm{.}115\mathrm{.}216\mathrm{.}0$ Extrapolated air$-$gap voltage, kV $15\mathrm{.}417\mathrm{.}518\mathrm{.}322\mathrm{.}827\mathrm{.}4$ The short$-$circuit test was then performed with the following results: Short$-$circuit test Field current, A $320365380475570$ Armature current, A $10401190124015501885$ The armature resistance is $0\mathrm{.}6$ per phase. $($a$)$ Find the unsaturated synchronous reactance ofthis generator in ohms per phase and ohms per unit. $($b$)$ Find the approximate saturated synchronous reactance Xs at a field current of $380$ A$.$ Express the answer both in ohms per phase and per unit. SYNCHRONOUS GENERATORS $267($c$)$ Find the approximate saturated synchronous reactance at a field current of $475$ A$.$ Express the answer both in ohms per phase and in per unit. $($d$)$ Find the short$-$circuit ratio for this generator. $($e$)$ What is the internal generated voltage of this generator at rated conditions? $($f$)$ What field current is required to achieve rated voltage at rated load?