DGVCL Exam Paper (11-12-2011) The insulation coordination for UHV lines (above 500 kV) is done based on Switching surges Voltage level of the line Lightning and switching surges Lightning surges Switching surges Voltage level of the line Lightning and switching surges Lightning surges ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The main advantage of using fractional pitch winding is to refuce Harmonics in the generated emf Amount of copper in the winding Size of the machine Cost of the machine Harmonics in the generated emf Amount of copper in the winding Size of the machine Cost of the machine ANSWER EXPLANATION DOWNLOAD EXAMIANS APP due to fractional pitch EMF can be approximately made into sine wavelosses due to harmonics reducedsaving in conductor materialmechanical strength of coil is increased.
DGVCL Exam Paper (11-12-2011) The purpose of providing a choke in a tube light is To avoid radio interference To eliminate corona effect To improve the power factor To limit the current to an appropriate value To avoid radio interference To eliminate corona effect To improve the power factor To limit the current to an appropriate value 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 0.6 lagging 0.8 lagging 0.5 leading 0.6 leading 0.6 lagging 0.8 lagging 0.5 leading 0.6 leading 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 6 H 2.2 H 36 H 13 H 6 H 2.2 H 36 H 13 H 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% 80 % 90 % More than 90% Less than 90% 80 % 90 % 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
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