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% More than 90% 90 % 80 % Less than 90% More than 90% 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) If a relay fails to operate inspite of a fault in its own zone of protection, it is said to Over reach Reach Under reach Pick up Over reach Reach Under reach Pick up ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) In which of the following motors, the stator and rotor magnetic fields rotate at the same speed? Universal motor Reluctance motor Synchronous motor Induction motor Universal motor Reluctance motor Synchronous motor Induction motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP In all machine stator and rotor magnetic field rotates (stationary with respect to each other) at synchronous speed with respect to stationary observer.
DGVCL Exam Paper (11-12-2011) Different computers are connected to a LAN by a cable and a Special wires Telephone line Modem Interface card Special wires Telephone line Modem Interface card ANSWER DOWNLOAD EXAMIANS APP
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 average value R.M.S. value to peak value Peak value to average value Peak value to r.m.s value R.M.S. value to average value R.M.S. value to peak value Peak value to average value ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Under operating conditions, the secondary of a current transformer is always short ciruited because It is safe to human beings It avoids core saturation and high voltage induction It protects the primary ciruits It protects the secondary ciruits It is safe to human beings It avoids core saturation and high voltage induction It protects the primary ciruits It protects the secondary ciruits ANSWER DOWNLOAD EXAMIANS APP
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