DGVCL Exam Paper (11-12-2011) Ybus used in power flow studies and Zbus used in short circuit studies Are the same Have no inter relation Are inverse of each other Are transpose of each other Are the same Have no inter relation Are inverse of each other Are transpose of each other ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) A 3 phase, 6 pole induction motor operates on 440 V, 50 Hz, supply. If the actual speed of the motor is 960 rpm the slip will be 0.4 % 5 % 6 % 4 % 0.4 % 5 % 6 % 4 % ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ns = 120f/PSlip=(Ns-Nr)/NsNs = 1000 and Nr = 960 from equation of slip, S = (1000-960)/1000S = 0.04 or 4%
DGVCL Exam Paper (11-12-2011) Bulk power transmission over long HVDC lines are preferred on account of No harmonic problems Low cost of HVDC terminals Minimum line power losses Simple protection No harmonic problems Low cost of HVDC terminals Minimum line power losses Simple protection ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The transient stability of a power system can be improved by Single pole switching of circuit breakers Phase shifting transformer Excitation control Increasing the turbine valve opening Single pole switching of circuit breakers Phase shifting transformer Excitation control Increasing the turbine valve opening ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The purpose of interpoles in DC machines is to nullify The reactance voltage Both the cross-magnetizing mmf and the reactance voltage The cross-magnetizing effect of armature mmf The demagnetizing effect of armature mmf The reactance voltage Both the cross-magnetizing mmf and the reactance voltage The cross-magnetizing effect of armature mmf The demagnetizing effect of armature mmf ANSWER EXPLANATION DOWNLOAD EXAMIANS APP interpoles is widely use to improve commutationplace between main poles fitted to yokefunctions:to neutralize armature mmf in commutating zoneto produce some flux in commutating zone
DGVCL Exam Paper (11-12-2011) Permittivity is expressed in terms of Farad/m Weber /m N/m farad/sq. m. Farad/m Weber /m N/m farad/sq. m. ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS