DGVCL Exam Paper (11-12-2011) The circuit breaker generally used in railway traction is Air break CB Vacuum CB Bulk Oil CB Minimum Oil CB Air break CB Vacuum CB Bulk Oil CB Minimum Oil CB ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) At time t= 0+ , with zero initial condition, which of the following acts as a short circuit? Capacitor Voltage source Conductor Resistor Capacitor Voltage source Conductor Resistor ANSWER DOWNLOAD EXAMIANS APP
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 % 4 % 6 % 0.4 % 5 % 4 % 6 % 0.4 % 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) The picture on the monitor of a computer is made up of tiny coloured dots called Points Spots Icons Pixels Points Spots Icons Pixels 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 Less than 90% 80 % 90 % More than 90% Less than 90% 80 % 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) The purpose of interpoles in DC machines is to nullify The cross-magnetizing effect of armature mmf Both the cross-magnetizing mmf and the reactance voltage The reactance voltage The demagnetizing effect of armature mmf The cross-magnetizing effect of armature mmf Both the cross-magnetizing mmf and the reactance voltage The reactance voltage The demagnetizing effect of armature mmf ANSWER EXPLANATION DOWNLOAD EXAMIANS APP interpoles is widely use to improve commutationplace between main poles fitted to yokefunctions:to neutralize armature mmf in commutating zoneto produce some flux in commutating zone
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