DGVCL Exam Paper (11-12-2011) In the protection of transformers, harmonic restraint is used to guard against Magnetizing inrush current Switching over voltages Lightning Unbalanced protection Magnetizing inrush current Switching over voltages Lightning 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) The form factor in AC means the ration of Peak value to r.m.s value Peak value to average value R.M.S. value to peak value R.M.S. value to average value Peak value to r.m.s value Peak value to average value R.M.S. value to peak value R.M.S. value to average value ANSWER DOWNLOAD EXAMIANS APP
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
DGVCL Exam Paper (11-12-2011) People can interact with each other through any part of the world through video conferencing using Scanner Webcam Speaker Joystick Scanner Webcam Speaker Joystick ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The purpose of providing a choke in a tube light is To avoid radio interference To improve the power factor To limit the current to an appropriate value To eliminate corona effect To avoid radio interference To improve the power factor To limit the current to an appropriate value To eliminate corona effect 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 6 % 5 % 4 % 0.4 % 6 % 5 % 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%
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