DBATU Model MCQ – Electrical Machines 2Spread the love Views: 132[adinserter block="1"] Welcome to your Electrical Machine 2, dated April 20, 2021 1. A differential relay comparator used for the protection of three phase transformers hasDeselect AnswerOne comparatorTwo comparatorThree comparatorSix comparator 2. In double delta transformation, a double delta refers to the case where there are two delta transformations inDeselect AnswerParallelSeriesBoth series and parallelNeither series nor parallel 3. In Scott connection, the voltage across the teaser leads the mains byDeselect Answer30 degree90 degree60 degree1200 degree 4. For large low voltage transformers, the most commonly used connections areDeselect AnswerStar - star connectionDelta - delta connectionV connectionAll of these 5. In a three phase transformer, the current flowing in three primaries produces three corresponding fluxes. The sum of these three fluxes at any instant isDeselect AnswerZeroThree times of any individual fluxOne third of any individual fluxNone of these 6. The constant current transformer are mainly used forDeselect AnswerSupplying series connected street lightPersonal computersArc weldingElectric toys 7. Small iron core transformers used in certain frequency range is also called audio frequency transformer. The audio frequency range isDeselect Answer20 to 2000 Hz20 to 20000 Hz2 to 2000 Hz200 to 20000 Hz 8. The output voltage of constant voltage transformer contains excessive harmonics which can be filtered out by usingDeselect AnswerRC filterRL filterLC filterNone of these 9. A constant voltage transformer is fed with the sinusoidal input voltage. Its output isDeselect AnswerSinusoidalFlat toppedSaw toothZig-zag 10. A star connected three phase transformer is provided with tertiary delta connected winding which allows the flow ofDeselect AnswerSecond harmonic of exciting currentThird harmonic of exciting currentFifth harmonic of exciting currentSeventh harmonic of exciting current Please fill in the comment box below. [adinserter block="1"]Spread the love