DGVCL Exam Paper (11-12-2011) People can interact with each other through any part of the world through video conferencing using Speaker Scanner Webcam Joystick Speaker Scanner Webcam Joystick ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) An over excited synchronous motor draws current at Lagging power factor Depends on nature of load Unity power factor Leading power factor Lagging power factor Depends on nature of load Unity power factor Leading power factor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Over excitation : leading currentUnder excitation : lagging currentNormal excitation : current with unity PF (in phase current)
DGVCL Exam Paper (11-12-2011) Which of the following power distribution system gives better reliabity ? Radial system None of these DC 3 wire system Ring main system Radial system None of these DC 3 wire system Ring main system 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 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) A 3 phase, 6 pole induction motor operates on 440 V, 50 Hz, supply. If the actual speed of the motor is 960 rpm the slip will be 5 % 0.4 % 4 % 6 % 5 % 0.4 % 4 % 6 % ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Ns = 120f/PSlip=(Ns-Nr)/NsNs = 1000 and Nr = 960 from equation of slip, S = (1000-960)/1000S = 0.04 or 4%
DGVCL Exam Paper (11-12-2011) Which lightning stroke is most dangerous? Direct stoke on tower top Direct stroke on ground wire Indirect stroke on conductor Direct stroke on line conductor Direct stoke on tower top Direct stroke on ground wire Indirect stroke on conductor Direct stroke on line conductor ANSWER DOWNLOAD EXAMIANS APP
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