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 50 MVA 10 MVA 60 MVA 20 MVA 50 MVA 10 MVA 60 MVA 20 MVA ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Short circuit kVA = Base kVA/%X
DGVCL Exam Paper (11-12-2011) In the protection of transformers, harmonic restraint is used to guard against Lightning Magnetizing inrush current Switching over voltages Unbalanced protection Lightning Magnetizing inrush current Switching over voltages 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) Which lightning stroke is most dangerous? Direct stroke on ground wire Direct stroke on line conductor Indirect stroke on conductor Direct stoke on tower top Direct stroke on ground wire Direct stroke on line conductor Indirect stroke on conductor Direct stoke on tower top 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 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 increased The force increases when the distance between the conductors is decreased 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 increased ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Transposition of transmission line is done to Reduce skin effect Reduce line loss Balance line voltage drop Reduce corona Reduce skin effect Reduce line loss Balance line voltage drop Reduce corona ANSWER DOWNLOAD EXAMIANS APP
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 directional proporational to torque Torque and speed are inversely proportional to the square of the armature current Torque and speed are proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is inversely proportional to torque Its torque is proportional to the square of the armature current and speed is directional proporational to torque Torque and speed are inversely proportional to the square of the armature current Torque and speed are proportional to the square of the armature current Its torque is proportional to the square of the armature current and speed is inversely proportional 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
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