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 4 % 6 % 0.4 % 5 % 4 % 6 % 0.4 % 5 % 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) In a series RLC circuit at resonance Current is maximum and power factor is unity Current is minimum and power factor is 0.5 Current is minimum and power factor is unity Current is maximum and power factor is 0.5 Current is maximum and power factor is unity Current is minimum and power factor is 0.5 Current is minimum and power factor is unity Current is maximum and power factor is 0.5 ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) People can interact with each other through any part of the world through video conferencing using Scanner Joystick Speaker Webcam Scanner Joystick Speaker Webcam ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Under operating conditions, the secondary of a current transformer is always short ciruited because It protects the secondary ciruits It avoids core saturation and high voltage induction It is safe to human beings It protects the primary ciruits It protects the secondary ciruits It avoids core saturation and high voltage induction It is safe to human beings It protects the primary ciruits ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The transient stability of a power system can be improved by Phase shifting transformer Increasing the turbine valve opening Single pole switching of circuit breakers Excitation control Phase shifting transformer Increasing the turbine valve opening Single pole switching of circuit breakers Excitation control ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The efficiency of a transformer at full load, 0.8 p.f. lag is 90%. Its efficiency at full load, 0.8 p.f. lead will be Less than 90% More than 90% 90 % 80 % Less than 90% More than 90% 90 % 80 % ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Efficiency= output power/input powerefficiency = (v*i*cosφ)/((v*i*cosφ)+(x² Pc)+(Pi)) x=fractional part of full load
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