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 90 % 80 % More than 90% Less than 90% 90 % 80 % More than 90% Less 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) 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) People can interact with each other through any part of the world through video conferencing using Scanner Joystick Webcam Speaker Scanner Joystick Webcam Speaker ANSWER DOWNLOAD EXAMIANS APP
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 10 MVA 50 MVA 60 MVA 20 MVA 10 MVA 50 MVA 60 MVA 20 MVA ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Short circuit kVA = Base kVA/%X
DGVCL Exam Paper (11-12-2011) Two parallel conductors are carrying the current in the same direction. Which of the following statements is correct? The force increases when the distance between the conductors is decreased The force increases when the distance between the conductors is increased There is a repelling force between the conductors There is an attracting force between the conductors The force increases when the distance between the conductors is decreased The force increases when the distance between the conductors is increased There is a repelling force between the conductors There is an attracting force between the conductors ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) An over excited synchronous motor draws current at Unity power factor Leading power factor Depends on nature of load Lagging power factor Unity power factor Leading power factor Depends on nature of load Lagging power factor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Over excitation : leading currentUnder excitation : lagging currentNormal excitation : current with unity PF (in phase current)
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