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 80 % More than 90% Less than 90% 90 % 80 % More than 90% Less than 90% 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) The positive and negative sequence impedance of a transmission line are Equal Zero Different Infinite Equal Zero Different Infinite ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) What happens to the contents of RAM (Random Access Memory) when the power of the computer is turned off? Content gets corrupted Content is transferred to other memory Content is lost Content remains intact Content gets corrupted Content is transferred to other memory Content is lost Content remains intact ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Fot fast load flow calculations, the best method is Approximate method Gauss-Siedal Newton-Raphson De-coupled method Approximate method Gauss-Siedal Newton-Raphson De-coupled method ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) In the protection of transformers, harmonic restraint is used to guard against Unbalanced protection Magnetizing inrush current Switching over voltages Lightning Unbalanced protection Magnetizing inrush current Switching over voltages Lightning 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) Permittivity is expressed in terms of Farad/m N/m Weber /m farad/sq. m. Farad/m N/m Weber /m farad/sq. m. ANSWER DOWNLOAD EXAMIANS APP
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