$4-9.$ A $480-$V$,250-$kVA, $0\mathrm{.}8-$PF$-$lagging, two$-$pole, three$-$phase, $60-$Hz synchronous gen erator's prime mover has a no$-$load speed of $3650$ rlmin and a full$-$load speed of $3570$ r$/$min$.$ It is operating in parallel with a $480-$V$,250-$kVA, $0\mathrm{.}85-$PF$-$Iagging, four pole, $60-$Hz synchronous generator whose prime mover has a no$-$load speed of $1800$ rlmin and a full$-$load speed of $1780$ rlmin. The loads supplied by the two gen erators consist of $300$ kW at $0\mathrm{.}8$ PF lagging. $($a$)$ Calculate the speed droops of generator $1$ and generator $2.($b$)$ Find the operating frequency of the power system. $($e$)$ Find the power being supplied by each of the generators in this system. $($d$)$ Vlhat must the generator's operators do to adjust the operating frequency to $60$ Hz$?($e$)$ If the current line voltage is $460$ V$,$ what must the generator's operators do to correct for the low terminal voltage?