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 insulation coordination for UHV lines (above 500 kV) is done based on Switching surges Voltage level of the line Lightning and switching surges Lightning surges Switching surges Voltage level of the line Lightning and switching surges Lightning surges ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) What happens to the contents of RAM (Random Access Memory) when the power of the computer is turned off? Content is transferred to other memory Content remains intact Content is lost Content gets corrupted Content is transferred to other memory Content remains intact Content is lost Content gets corrupted ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Which motor is used to start heavy loads? Shunt motor Series motor Cumulatively compounded motor Differentially compounded motor Shunt motor Series motor Cumulatively compounded motor Differentially compounded motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Torque in d.c motor = k* φ * IaIn series motor φ α IaTα I²starting torque of dc series motor is high
DGVCL Exam Paper (11-12-2011) It is difficult interrupt a capacitive current because It has a leading power factor The restriking voltage can be high Current magnitude is very small Stored energy in the capacitor is very high It has a leading power factor The restriking voltage can be high Current magnitude is very small Stored energy in the capacitor is very high 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 % 4 % 5 % 6 % 0.4 % 4 % 5 % 6 % 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%
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