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% 80 % 90 % Less than 90% More than 90% 80 % 90 % 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) An IDMT relay provides An inverse characteristic for low values of the fault current and a definite time characteristic for high values of the fault current A definite time characteristic for low values of the failt current and an inverse characteristic for high values of the fault current An inverse time current characteristic A definite time cuttent characteristic An inverse characteristic for low values of the fault current and a definite time characteristic for high values of the fault current A definite time characteristic for low values of the failt current and an inverse characteristic for high values of the fault current An inverse time current characteristic A definite time cuttent characteristic ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) DC series motors are best suited for traction work because Torque and speed are proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is directional proporational to torque Torque and speed are inversely proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is inversely proportional to torque Torque and speed are proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is directional proporational to torque Torque and speed are inversely proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is inversely proportional to torque ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Torque in d.c motor = k* φ * IaIn series motor φ α IaTα I²N α 1/φN α 1/T
DGVCL Exam Paper (11-12-2011) Which of the following correctly represents the sequence of operations of isolator, circiut breaker and earthing switch while opening a circuit? Open isolator close circuit breaker-open earthing switch Close circuit breaker-close isolator - open earthing switch Close earthing switch - open ciruit- breaker-open islotor Open circuit breaker-open isolator-close earthing switch Open isolator close circuit breaker-open earthing switch Close circuit breaker-close isolator - open earthing switch Close earthing switch - open ciruit- breaker-open islotor Open circuit breaker-open isolator-close earthing switch ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) If a 5 A fuse is blown frequently in a house lighting circuit, it is required to Check the load Insert a fuse of higher current rating Insert a fuse of higher voltage rating Reduce the load Check the load Insert a fuse of higher current rating Insert a fuse of higher voltage rating Reduce the load ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Which lightning stroke is most dangerous? Direct stoke on tower top Direct stroke on ground wire Indirect stroke on conductor Direct stroke on line conductor Direct stoke on tower top Direct stroke on ground wire Indirect stroke on conductor Direct stroke on line conductor ANSWER DOWNLOAD EXAMIANS APP
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