DGVCL Exam Paper (11-12-2011) The purpose of providing a choke in a tube light is To limit the current to an appropriate value To avoid radio interference To eliminate corona effect To improve the power factor To limit the current to an appropriate value To avoid radio interference To eliminate corona effect To improve the power factor ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) In which of the following motors, the stator and rotor magnetic fields rotate at the same speed? Induction motor Universal motor Synchronous motor Reluctance motor Induction motor Universal motor Synchronous 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) 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 20 MVA 10 MVA 50 MVA 60 MVA 20 MVA 10 MVA 50 MVA 60 MVA ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Short circuit kVA = Base kVA/%X
DGVCL Exam Paper (11-12-2011) An over excited synchronous motor draws current at Lagging power factor Depends on nature of load Unity power factor Leading power factor Lagging power factor Depends on nature of load Unity power factor 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) What type of insulator is used if the direction of the transmission line is to be changed? Suspebsion type Shakle type Strain type Pin type Suspebsion type Shakle type Strain type Pin type ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The transient stability of a power system can be improved by Single pole switching of circuit breakers Increasing the turbine valve opening Excitation control Phase shifting transformer Single pole switching of circuit breakers Increasing the turbine valve opening Excitation control Phase shifting transformer ANSWER DOWNLOAD EXAMIANS APP
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