A $500-$V$,37\mathrm{.}3$ kW$,1000$ r$.$p$.$m$.$ DC shunt motor has on full$-$load an efficiency of $90\%.$ The armature circuit resistance is $0\mathrm{.}24$ and there is total voltage drop of $2$ V at the brushes. The field current is $1\mathrm{.}8$ A$.$ Determine $($i$)$ Full$-$load line current $($ii$)$ Full load shaft torque in N$.$m $($iii$)$ Rotational loss in W $($iv$)($iv$)$ Total resistance in motor starter to limit the starting current to $1\mathrm{.}5$ times the full$-$load current.