Q$8$: A $10-$hp$,208-$V$,60-$Hz$,6-$pole, three$-$phase, Y$-$connected, synchronous

motor has a synchronous impedance of $0\mathrm{.}25+$j$3\mathrm{.}5(\backslash$Omega $)/()$ phase. The friction and

windage loss are $450$ W $,$ the core loss is $250$ W $,$ and the field$-$excitation loss is

$100$ W $.$ Determine $($a$)$ the armature current, $($b$)$ the torque angle, $($c$)$ the shaft

torque, and $($d$)$ the efficiency when the motor operates at full load with a unity

power factor.

Answers: $23\mathrm{.}85$ A$,-36\mathrm{.}2\backslash$deg $,59\mathrm{.}36$Nm$,86\%$