advertisement

EE 301 HW#37 AC Generators Part II la.) For a 4 pole, 60 Hz generator, determine the speed in rpm of the rotor: b.) For a 2 pole rotor operating at 7200 rpm, determine the frequency of the electrical signal. + == Np C#-fb~~_ ~(J200) 1;)0 ::2 /20 c.) How many poles would a generator need if it operated at half the rotor speed of problem (1 b), bllt produced the same frequel1cy? +- j:L CJ Np ~ CJ d- v Xl f).()) Lf po If>S "3{,oo 2) Given: At a hydroelectric plant on the great Coilimbia River, a 3-phase, Y-connected synchrol10us generator is rated at 300 MVA, 60Hz and 25KV. It operates with a lagging power factor of 0.75 and negligible armature resistance and reactance. Use Van as the voltage reference. /l Reg'd: ~f'.J /f'J a) Fil1d the line current phasor I a . (This would include the angle!). b) Draw the p"ower conversion diagram. c) If there are no mechanical losses, find PIN. What is the efficiency of this generator? f; N ~ r/ -I- r} f ~v + /f}~ j EE 301 HW#37 AC Generators Part II '3) Given: A Y-conl1ected, 4-pole, 3-phase, 2.2 KV, 60Hz synchronous generator with 0.060 per phase resistance supplies rated line voltage/current to a Y connected load with a 0.85 lagging' power factor. The power Ollt is 1.492 MW. The nlechanicallosses are 92KW. Use Van as the voltage reference Reg'd: a) Find Ia (pha-sor). b) What is the effiCie~Cy. of t.he generator? . . c) Draw the power conversion diagram. . d) At what speed does the shaft rotate (rpm)? / e) What is the prime mover tor:que? ~ ~ := ~.~ V~l1- ~ ItLl~Jj\1W ---:­ .-L a .-:-J- l­ N := 8 . VCtf\ - - J-Cl:::: LJ {p IA L -3l Cos --I 'Fp o - eo] -(;;). (tp =- ~~ I , ~ 0 ~o 0 _ ) ,tV - -=== L Lf 9d.- (Yl ().J -JI L{ ~d.. (Y\W + t 3lc;-:t Rq I) + 0 '?:> '$J. yY)w ~j~~r~:: ~ - -1iCM{~o .CJd.-' . If {P'7J-'l~ , ­ +- ·f I 0 Cj d- (Y1 W 09:2 (VI W TPrr\~ ­ P,IU W L Co 'J..J. fY\w !1(Pg2(YlW Cco'?i -- =l~,&II-fN.~ -­ ~~~~.~~~~~~\~.~~~.~(~~~~f.~~~~+ J,~g~m~ Z ~~ ? p(y) Wr -, ~ 1'~d-d-(Y\uJ I _~ ­