DBATU Model MCQ – Electrical Machines 2 Views: 531 [adinserter block="1"] Welcome to your Electrical Machine 2, dated May 30, 2023 1. A differential relay comparator used for the protection of three phase transformers has Deselect Answer One comparator Two comparator Three comparator Six comparator 2. In double delta transformation, a double delta refers to the case where there are two delta transformations inDeselect Answer Parallel Series Both series and parallel Neither series nor parallel 3. In Scott connection, the voltage across the teaser leads the mains byDeselect Answer 30 degree 90 degree 60 degree 1200 degree 4. For large low voltage transformers, the most commonly used connections areDeselect Answer Star - star connection Delta - delta connection V connection All 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 Answer Zero Three times of any individual flux One third of any individual flux None of these 6. The constant current transformer are mainly used forDeselect Answer Supplying series connected street light Personal computers Arc welding Electric toys 7. Small iron core transformers used in certain frequency range is also called audio frequency transformer. The audio frequency range isDeselect Answer 20 to 2000 Hz 20 to 20000 Hz 2 to 2000 Hz 200 to 20000 Hz 8. The output voltage of constant voltage transformer contains excessive harmonics which can be filtered out by usingDeselect Answer RC filter RL filter LC filter None of these 9. A constant voltage transformer is fed with the sinusoidal input voltage. Its output isDeselect Answer Sinusoidal Flat topped Saw tooth Zig-zag 10. A star connected three phase transformer is provided with tertiary delta connected winding which allows the flow ofDeselect Answer Second harmonic of exciting current Third harmonic of exciting current Fifth harmonic of exciting current Seventh harmonic of exciting current Please fill in the comment box below. [adinserter block="1"]
