DGVCL Exam Paper (11-12-2011) Under operating conditions, the secondary of a current transformer is always short ciruited because It protects the primary ciruits It is safe to human beings It protects the secondary ciruits It avoids core saturation and high voltage induction It protects the primary ciruits It is safe to human beings It protects the secondary 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% 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
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? Close circuit breaker-close isolator - open earthing switch Open circuit breaker-open isolator-close earthing switch Open isolator close circuit breaker-open earthing switch Close earthing switch - open ciruit- breaker-open islotor Close circuit breaker-close isolator - open earthing switch Open circuit breaker-open isolator-close earthing switch Open isolator close circuit breaker-open earthing switch Close earthing switch - open ciruit- breaker-open islotor ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Buchholz relay causes Tripping for both major and minor faults Tripping for major faults and alarm for minor faults Alarm for both major and minor faults Tripping for minor faults and alarm for major faults Tripping for both major and minor faults Tripping for major faults and alarm for minor faults Alarm for both major and minor faults Tripping for minor faults and alarm for major faults ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) An AC series circuit has R = 6 Ω, XL = 20 Ω and Xc = 12 Ω. The ciruit power factor will be 0.5 leading 0.6 leading 0.6 lagging 0.8 lagging 0.5 leading 0.6 leading 0.6 lagging 0.8 lagging ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) If the excitation of a synchronous generator fails, it acts as a Induction generator Synchronous generator Induction motor Synchronous motor Induction generator Synchronous generator Induction motor Synchronous motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP if excitation of synchronous generator fails, operate as induction motor
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