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 % Less than 90% 90 % More than 90% 80 % Less than 90% 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
DGVCL Exam Paper (11-12-2011) A fuse is inserted in Both phased and neutral wire Earth continuity conductor Phase wire Neutral wire Both phased and neutral wire Earth continuity conductor Phase wire Neutral wire ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The circuit breaker generally used in railway traction is Minimum Oil CB Vacuum CB Bulk Oil CB Air break CB Minimum Oil CB Vacuum CB Bulk Oil CB Air break CB ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) In a series RLC circuit at resonance Current is maximum and power factor is unity Current is maximum and power factor is 0.5 Current is minimum and power factor is unity Current is minimum and power factor is 0.5 Current is maximum and power factor is unity Current is maximum and power factor is 0.5 Current is minimum and power factor is unity Current is minimum and power factor is 0.5 ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The transient stability of a power system can be improved by Increasing the turbine valve opening Phase shifting transformer Single pole switching of circuit breakers Excitation control Increasing the turbine valve opening Phase shifting transformer Single pole switching of circuit breakers Excitation control ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) If the fault current is 2000 A, the relay plug setting is 50% and the CT ratio is 400/5, the plug setting multiple will be 25 10 50 15 25 10 50 15 ANSWER DOWNLOAD EXAMIANS APP