DGVCL Exam Paper (11-12-2011) Which type of back up protection is widely used for the protection of transmission lines? Control backup Breaker backup Relay backup Remote backup Control backup Breaker backup Relay backup Remote backup ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) A Mho relay is a Directional restrained over voltage relay Voltage restrained directional relay Directional restrained over current relay Voltage controlled over current relay Directional restrained over voltage relay Voltage restrained directional relay Directional restrained over current relay Voltage controlled over current relay ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Rated making capacity of a ciruit breaker is equal to √2 X rated symmetrical breaking capacity 1.11 X rated symmetrical breaking capacity Rated symmetrical breaking capacity 2.55 X rated symmetrical breaking capacity √2 X rated symmetrical breaking capacity 1.11 X rated symmetrical breaking capacity Rated symmetrical breaking capacity 2.55 X rated symmetrical breaking capacity 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 5 % 6 % 0.4 % 4 % 5 % 6 % 0.4 % 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) 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 More than 90% 90 % Less than 90% 80 % More than 90% 90 % Less than 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
DGVCL Exam Paper (11-12-2011) What type of insulator is used if the direction of the transmission line is to be changed? Pin type Suspebsion type Strain type Shakle type Pin type Suspebsion type Strain type Shakle type ANSWER DOWNLOAD EXAMIANS APP
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