DGVCL Exam Paper (11-12-2011) The form factor in AC means the ration of Peak value to r.m.s value R.M.S. value to peak value R.M.S. value to average value Peak value to average value Peak value to r.m.s value R.M.S. value to peak value R.M.S. value to average value Peak value to average value ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) A Mho relay is a Directional restrained over voltage relay Voltage restrained directional relay Voltage controlled over current relay Directional restrained over current relay Directional restrained over voltage relay Voltage restrained directional relay Voltage controlled over current relay Directional restrained over current relay ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Which motor is used to start heavy loads? Differentially compounded motor Series motor Cumulatively compounded motor Shunt motor Differentially compounded motor Series motor Cumulatively compounded motor Shunt motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Torque in d.c motor = k* φ * IaIn series motor φ α IaTα I²starting torque of dc series motor is high
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 % More than 90% 80 % Less than 90% 90 % More than 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) The corona effect can be minimized by increasing Spacing between the conductors Diameter of the conductor The length of the conductor Both spacing between the conductors and diameter of the conductor Spacing between the conductors Diameter of the conductor The length of the conductor Both spacing between the conductors and diameter of the conductor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Corona can be reduced by using large size of conductor, bundle conductor and hollow conductor.
DGVCL Exam Paper (11-12-2011) An over excited synchronous motor draws current at Leading power factor Unity power factor Depends on nature of load Lagging power factor Leading power factor Unity 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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