DGVCL Exam Paper (11-12-2011) An IDMT relay provides An inverse characteristic for low values of the fault current and a definite time characteristic for high values of the fault current A definite time cuttent characteristic A definite time characteristic for low values of the failt current and an inverse characteristic for high values of the fault current An inverse time current characteristic An inverse characteristic for low values of the fault current and a definite time characteristic for high values of the fault current A definite time cuttent characteristic A definite time characteristic for low values of the failt current and an inverse characteristic for high values of the fault current An inverse time current characteristic ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Which of the following power distribution system gives better reliabity ? DC 3 wire system None of these Ring main system Radial system DC 3 wire system None of these Ring main system Radial system 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? Reluctance motor Induction motor Universal motor Synchronous motor Reluctance motor Induction motor Universal motor Synchronous 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) 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 % Less than 90% More than 90% 90 % 80 % Less than 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) Bulk power transmission over long HVDC lines are preferred on account of Low cost of HVDC terminals Simple protection No harmonic problems Minimum line power losses Low cost of HVDC terminals Simple protection No harmonic problems Minimum line power losses ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The corona effect can be minimized by increasing The length of the conductor Spacing between the conductors Diameter of the conductor Both spacing between the conductors and diameter of the conductor The length of the conductor Spacing between the conductors Diameter of the conductor Both spacing between the conductors and diameter of the conductor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Corona can be reduced by using large size of conductor, bundle conductor and hollow conductor.
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