DGVCL Exam Paper (11-12-2011) A fuse wire should have High specific resistance and low melting point Low specific resistance and low melting point Low specific resistance and high melting point High specific resistance and high melting point High specific resistance and low melting point Low specific resistance and low melting point Low specific resistance and high melting point High specific resistance and high melting point 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% 90 % 80 % More than 90% Less than 90% 90 % 80 % More than 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) In the protection of transformers, harmonic restraint is used to guard against Switching over voltages Magnetizing inrush current Lightning Unbalanced protection Switching over voltages Magnetizing inrush current Lightning Unbalanced protection ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Initial inrush of magnetizing currents have high component of even and odd harmonics.2nd - 63%3rd -26.8%4th- 5.1%5th- 4.1%6th- 3.77th-2.4
DGVCL Exam Paper (11-12-2011) Hysteresis in an instrument means The inaccuracy due to change in temperature The reliability of the instrument The change in the same reading when the input is first increased and then decreased The repeatability of the instrument The inaccuracy due to change in temperature The reliability of the instrument The change in the same reading when the input is first increased and then decreased The repeatability of the instrument ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The mutual inductance between two unity coupled coils of 9 H and 4 H is 36 H 13 H 2.2 H 6 H 36 H 13 H 2.2 H 6 H ANSWER DOWNLOAD EXAMIANS APP
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
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