DGVCL Exam Paper (11-12-2011) If the percentage reactance of the system upto the point of fault is 20% and the base kVA is 10,000 the short ciruit kVA is 50 MVA 20 MVA 60 MVA 10 MVA 50 MVA 20 MVA 60 MVA 10 MVA ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Short circuit kVA = Base kVA/%X
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 earthing switch - open ciruit- breaker-open islotor Open circuit breaker-open isolator-close earthing switch Close circuit breaker-close isolator - open earthing switch Open isolator close circuit breaker-open earthing switch Close earthing switch - open ciruit- breaker-open islotor Open circuit breaker-open isolator-close earthing switch Close circuit breaker-close isolator - open earthing switch ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Rated making capacity of a ciruit breaker is equal to 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 √2 X rated symmetrical breaking capacity 1.11 X rated symmetrical breaking capacity ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Which of the following power distribution system gives better reliabity ? Ring main system DC 3 wire system None of these Radial system Ring main system DC 3 wire system None of these Radial system 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 is safe to human beings It protects the primary ciruits It avoids core saturation and high voltage induction It protects the secondary ciruits It is safe to human beings It protects the primary ciruits It avoids core saturation and high voltage induction 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% 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
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