DGVCL Exam Paper (11-12-2011) If the percentage reactance of the system upto the point of fault is 20% and the base kVA is 10,000 the short ciruit kVA is 10 MVA 60 MVA 50 MVA 20 MVA 10 MVA 60 MVA 50 MVA 20 MVA ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Short circuit kVA = Base kVA/%X
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) DC series motors are best suited for traction work because Its torque is proportional to the square of the armature current and speed is inversely proportional to torque Torque and speed are proportional to the square of the armature current Torque and speed are inversely proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is directional proporational to torque Its torque is proportional to the square of the armature current and speed is inversely proportional to torque Torque and speed are proportional to the square of the armature current Torque and speed are inversely proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is directional proporational to torque ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Torque in d.c motor = k* φ * IaIn series motor φ α IaTα I²N α 1/φN α 1/T
DGVCL Exam Paper (11-12-2011) In the protection of transformers, harmonic restraint is used to guard against Lightning Magnetizing inrush current Unbalanced protection Switching over voltages Lightning Magnetizing inrush current Unbalanced protection Switching over voltages 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) People can interact with each other through any part of the world through video conferencing using Webcam Joystick Scanner Speaker Webcam Joystick Scanner Speaker ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) If the fault current is 2000 A, the relay plug setting is 50% and the CT ratio is 400/5, the plug setting multiple will be 25 50 10 15 25 50 10 15 ANSWER DOWNLOAD EXAMIANS APP
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