DGVCL Exam Paper (11-12-2011) The mutual inductance between two unity coupled coils of 9 H and 4 H is 36 H 2.2 H 6 H 13 H 36 H 2.2 H 6 H 13 H ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) Different computers are connected to a LAN by a cable and a Telephone line Interface card Special wires Modem Telephone line Interface card Special wires Modem ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) What type of insulator is used if the direction of the transmission line is to be changed? Shakle type Pin type Strain type Suspebsion type Shakle type Pin type Strain type Suspebsion 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 Phase shifting transformer Excitation control Increasing the turbine valve opening Single pole switching of circuit breakers Phase shifting transformer Excitation control Increasing the turbine valve opening ANSWER DOWNLOAD EXAMIANS APP
DGVCL Exam Paper (11-12-2011) The efficiency of a transformer at full load, 0.8 p.f. lag is 90%. Its efficiency at full load, 0.8 p.f. lead will be Less than 90% More than 90% 90 % 80 % Less than 90% More than 90% 90 % 80 % ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Efficiency= output power/input powerefficiency = (v*i*cosφ)/((v*i*cosφ)+(x² Pc)+(Pi)) x=fractional part of full load
DGVCL Exam Paper (11-12-2011) An over excited synchronous motor draws current at Unity power factor Leading power factor Lagging power factor Depends on nature of load Unity power factor Leading power factor Lagging power factor Depends on nature of load ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Over excitation : leading currentUnder excitation : lagging currentNormal excitation : current with unity PF (in phase current)
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