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 % 6 % 4 % 0.4 % 5 % 6 % 4 % 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 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 80 % 90 % Less than 90% More than 90% 80 % 90 % 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) Buchholz relay causes Tripping for minor faults and alarm for major faults Tripping for major faults and alarm for minor faults Tripping for both major and minor faults Alarm for both major and minor faults Tripping for minor faults and alarm for major faults Tripping for major faults and alarm for minor faults Tripping for both major and minor faults Alarm for both major and minor faults ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) What type of insulator is used if the direction of the transmission line is to be changed? Suspebsion type Strain type Shakle type Pin type Suspebsion type Strain type Shakle type Pin type ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Two parallel conductors are carrying the current in the same direction. Which of the following statements is correct? The force increases when the distance between the conductors is decreased The force increases when the distance between the conductors is increased There is a repelling force between the conductors There is an attracting force between the conductors The force increases when the distance between the conductors is decreased The force increases when the distance between the conductors is increased There is a repelling force between the conductors There is an attracting force between the conductors ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Rated making capacity of a ciruit breaker is equal to 2.55 X rated symmetrical breaking capacity 1.11 X rated symmetrical breaking capacity Rated symmetrical breaking capacity √2 X rated symmetrical breaking capacity 2.55 X rated symmetrical breaking capacity 1.11 X rated symmetrical breaking capacity Rated symmetrical breaking capacity √2 X rated symmetrical breaking capacity ANSWER DOWNLOAD EXAMIANS APP
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