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) The advantage of slipring induction motor over the squirrel cage induction motor is It is suitable for higher speeds It's power factor is higher It can be started with the help of rotor resistances It has a higher efficiency It is suitable for higher speeds It's power factor is higher It can be started with the help of rotor resistances It has a higher efficiency ANSWER EXPLANATION DOWNLOAD EXAMIANS APP slip ring motor have high starting torque compare to squirrel cage motor and have good speed controlalso have high over loading capacity, smooth acceleration under heavy loads.
DGVCL Exam Paper (11-12-2011) The effect of electric shock on the human body depends on Voltage All of these Duration of contact Current Voltage All of these Duration of contact Current 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 Single pole switching of circuit breakers Phase shifting transformer Excitation control Increasing the turbine valve opening Single pole switching of circuit breakers Phase shifting transformer Excitation control 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 remains intact Content gets corrupted Content is lost Content is transferred to other memory Content remains intact Content gets corrupted Content is lost Content is transferred to other memory 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 0.5 leading 0.6 leading 0.8 lagging 0.6 lagging 0.5 leading 0.6 leading 0.8 lagging ANSWER DOWNLOAD EXAMIANS APP
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