DGVCL Exam Paper (11-12-2011) In the protection of transformers, harmonic restraint is used to guard against Unbalanced protection Lightning Switching over voltages Magnetizing inrush current Unbalanced protection Lightning Switching over voltages Magnetizing inrush current 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) In which of the following motors, the stator and rotor magnetic fields rotate at the same speed? Synchronous motor Universal motor Induction motor Reluctance motor Synchronous motor Universal motor Induction motor Reluctance motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP In all machine stator and rotor magnetic field rotates (stationary with respect to each other) at synchronous speed with respect to stationary observer.
DGVCL Exam Paper (11-12-2011) An over excited synchronous motor draws current at Unity power factor Lagging power factor Depends on nature of load Leading power factor Unity power factor Lagging power factor Depends on nature of load Leading power factor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Over excitation : leading currentUnder excitation : lagging currentNormal excitation : current with unity PF (in phase current)
DGVCL Exam Paper (11-12-2011) An IDMT relay provides An inverse characteristic for low values of the fault current and a definite time characteristic for high values of the fault current An inverse time current characteristic A definite time characteristic for low values of the failt current and an inverse characteristic for high values of the fault current A definite time cuttent characteristic An inverse characteristic for low values of the fault current and a definite time characteristic for high values of the fault current An inverse time current characteristic A definite time characteristic for low values of the failt current and an inverse characteristic for high values of the fault current A definite time cuttent characteristic ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The effect of electric shock on the human body depends on Current Duration of contact All of these Voltage Current Duration of contact All of these Voltage ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Hysteresis in an instrument means The repeatability of the instrument The reliability of the instrument The change in the same reading when the input is first increased and then decreased The inaccuracy due to change in temperature The repeatability of the instrument The reliability of the instrument The change in the same reading when the input is first increased and then decreased The inaccuracy due to change in temperature ANSWER DOWNLOAD EXAMIANS APP
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