DGVCL Exam Paper (11-12-2011) Rated making capacity of a ciruit breaker is equal to √2 X rated symmetrical breaking capacity 2.55 X rated symmetrical breaking capacity Rated symmetrical breaking capacity 1.11 X rated symmetrical breaking capacity √2 X rated symmetrical breaking capacity 2.55 X rated symmetrical breaking capacity Rated symmetrical breaking capacity 1.11 X rated symmetrical breaking capacity ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Which lightning stroke is most dangerous? Direct stroke on line conductor Direct stroke on ground wire Indirect stroke on conductor Direct stoke on tower top Direct stroke on line conductor Direct stroke on ground wire Indirect stroke on conductor Direct stoke on tower top ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) In the protection of transformers, harmonic restraint is used to guard against Switching over voltages Lightning Magnetizing inrush current Unbalanced protection Switching over voltages Lightning Magnetizing inrush current Unbalanced protection ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Initial inrush of magnetizing currents have high component of even and odd harmonics.2nd - 63%3rd -26.8%4th- 5.1%5th- 4.1%6th- 3.77th-2.4
DGVCL Exam Paper (11-12-2011) If the excitation of a synchronous generator fails, it acts as a Synchronous motor Induction motor Induction generator Synchronous generator Synchronous motor Induction motor Induction generator Synchronous generator ANSWER EXPLANATION DOWNLOAD EXAMIANS APP if excitation of synchronous generator fails, operate as induction motor
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 4 % 5 % 6 % 0.4 % 4 % 5 % 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) Under operating conditions, the secondary of a current transformer is always short ciruited because It avoids core saturation and high voltage induction It protects the secondary ciruits It protects the primary ciruits It is safe to human beings It avoids core saturation and high voltage induction It protects the secondary ciruits It protects the primary ciruits It is safe to human beings ANSWER DOWNLOAD EXAMIANS APP
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