GETCO Exam Paper (22-07-2015) A transformer has negative voltage regulation when its load PF is leading zero lagging unity leading zero lagging unity ANSWER EXPLANATION DOWNLOAD EXAMIANS APP Voltage regulation = ((no load voltage)-(full load voltage)/(no load voltage))VR at leading PF = ((I*R*cosφ)-(I*X*sinφ))/VVR at lagging PF = ((I*R*cosφ)+(I*X*sinφ))/V
GETCO Exam Paper (22-07-2015) In case of a balanced three phase sinusoidal AC supply, because of the phase difference all are correct rotating magnetic field is produced neutral wire is not required, if load is balanced neutral current is high if load is not balanced all are correct rotating magnetic field is produced neutral wire is not required, if load is balanced neutral current is high if load is not balanced ANSWER DOWNLOAD EXAMIANS APP
GETCO Exam Paper (22-07-2015) For eliminating 7th harmonics from generated EMF in alternator the fractional pitch must be 6\7 7\8 5\6 2\3 6\7 7\8 5\6 2\3 ANSWER EXPLANATION DOWNLOAD EXAMIANS APP fractional pitch = Cos( α/2)α is obtain from: (nα/2)=90˚ where n is harmonicα=25.7143˚fractional pitch=6/7
GETCO Exam Paper (22-07-2015) Which of the following is not true about fuel cells? cost is higher than batteries need more than two electrode more efficient no recharging is needed cost is higher than batteries need more than two electrode more efficient no recharging is needed ANSWER DOWNLOAD EXAMIANS APP
GETCO Exam Paper (22-07-2015) Hopkinson's test is the test to be carried out on induction motor with any DC motor two identical induction motors two identical DC motors induction motor with synchronous motor induction motor with any DC motor two identical induction motors two identical DC motors induction motor with synchronous motor ANSWER EXPLANATION DOWNLOAD EXAMIANS APP In hopkinson test known as regenerative testtwo identical machine coupledD.C shunt motorD.C shunt generatortemperature rise can be check under rated conditionlarge machine can be tested without drawing much power.
GETCO Exam Paper (22-07-2015) For formation of the Y bus matrix (using node voltage analysis) in power system network modelling _____ is used KCL KVL all are correct Faraday's law KCL KVL all are correct Faraday's law ANSWER DOWNLOAD EXAMIANS APP
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