ELECTRICIAN 1st YEAR MODULE -Transformer July 2, 2025June 30, 2025 by admin TRANSLATE THIS QUIZ IN YOUR LANGUAGE इस प्रश्नोत्तरी का अपनी भाषा में अनुवाद करें <<1234567891011121314151617181920212223242526272829303132333435>> 0% Question 1 of 35 1. What condition gives maximum transformer efficiency? Copper loss = Eddy current loss Copper loss < Iron loss Copper loss = Iron loss Copper loss > Iron lossQuestion 1 of 35Question 2 of 35 2. What activates the top float switch in a Buchholz relay? Moisture presence High temperature condition Open circuit condition Overloading conditionQuestion 2 of 35Question 3 of 35 3. How is moisture controlled in transformer breathers? Transformer oil Sodium chloride Ammonium jelly Silica gelQuestion 3 of 35Question 4 of 35 4. What is the purpose of tap changing in power transformers? Maintain secondary voltage Maintain primary voltage Change distribution voltage ratio Optimize for maximum efficiencyQuestion 4 of 35Question 5 of 35 5. What type of transformer is this? Core type transformer Audio frequency transformer Shell type transformer Auto transformerQuestion 5 of 35Question 6 of 35 6. Which cooling method is used in pole-mounted distribution transformers? Oil natural air blast Oil natural air natural Air natural Oil forced air forcedQuestion 6 of 35Question 7 of 35 7. Why does a current transformer core have low reactance and low core losses? To minimize reading errors To maintain constant output To minimize the burden To prevent high static shieldQuestion 7 of 35Question 8 of 35 8. Why are ferrite cores used in radio receivers? Reduce constant losses Increase receiver efficiency Reduce electric interference Improve sound qualityQuestion 8 of 35Question 9 of 35 9. What is the function of Buchholz relay in power transformers? Protection from tank pressure Protection from moisture in oil Protection from overloading and short circuits Protection from high temperatureQuestion 9 of 35Question 10 of 35 10. How is copper loss determined in transformers? Impulse test Short circuit test Ratio test Open circuit testQuestion 10 of 35Question 11 of 35 11. Why is load disconnected before OFF-load tap changing? Avoid heavy sparking at contacts Disconnect diverter moving contact Disconnect tappings from neutral Provide electrical isolation for windingsQuestion 11 of 35Question 12 of 35 12. What is the relationship between primary voltage (E1 V1 ) and secondary voltage (E2, V2) in an ideal transformer? E1 < V1 and E2 < V2E1= V1 and E2 = V2E1 > V1 and E2 > V2E1 = V1 and E2 = V2Question 12 of 35Question 13 of 35 13. Why are laminated cores used in transformers? Reduce eddy current loss Reduce hysteresis loss Reduce copper loss Reduce mechanical lossQuestion 13 of 35Question 14 of 35 14. Why are distribution transformers typically delta-primary and star-secondary? Maintain constant voltage Reduce transformer losses Avoid overloading Facilitate 3-phase 4-wire distributionQuestion 14 of 35Question 15 of 35 15. Which transformer measures high voltage installations? Constant voltage transformers Ignition transformers Potential transformers Pulse transformersQuestion 15 of 35Question 16 of 35 16. What is the purpose of an explosion vent in power transformers? Air releasing Moisture releasing Pressure releasing Heat releasingQuestion 16 of 35Question 17 of 35 17. Which construction technique reduces copper loss in large transformers? Stepped core arrangement Reduced core thickness Laminated core Grain oriented coreQuestion 17 of 35Question 18 of 35 18. What is this power transformer component called? Tap charger Buchholz relay Breather Explosion ventQuestion 18 of 35Question 19 of 35 19. What type of EMF is induced in an ideal two-winding transformer? Dynamically induced EMF Mutually induced EMF Statically induced EMF Self induced EMFQuestion 19 of 35Question 20 of 35 20. Calculate the voltage regulation percentage if no-load voltage is 240V and full-load voltage is 220V: 8.30% 9.09% 7.20% 8.71%Question 20 of 35Question 21 of 35 21. What is the disadvantage of auto transformers? More losses Heavier weight Cannot isolate secondary winding Poor voltage regulationQuestion 21 of 35Question 22 of 35 22. What material is used in breathers to prevent moisture in transformer oil? Ammonium chloride Silica gel Charcoal-salt mixture Sodium chlorideQuestion 22 of 35Question 23 of 35 23. What is absolutely essential for parallel transformer operation? Type of cooling Phase sequence Insulation class Nature of loadQuestion 23 of 35Question 24 of 35 24. Why is the primary of a potential transformer wound with thin wire and many turns? To obtain required voltage ratio To regulate primary current To stabilize input/output voltage To offer high inductanceQuestion 24 of 35Question 25 of 35 25. What is the cooling method of transformers? Oil natural cooling Oil natural water forced cooling Oil forced air forced cooling Oil natural air forced coolingQuestion 25 of 35Question 26 of 35 26. Which material is used to make the core of power transformers? Rolled steel Cold rolled grain oriented steel Soft iron Copper alloyQuestion 26 of 35Question 27 of 35 27. How can potential transformer reading errors be reduced? Providing long magnetic path Using good quality core material Using thin laminated core Using high flux density materialQuestion 27 of 35Question 28 of 35 28. Which loss is assessed by open-circuit test? Hysteresis loss only Eddy current loss only Copper loss Core lossQuestion 28 of 35Question 29 of 35 29. What does the crackle test of transformer oil determine? Dielectric strength Viscosity Acidity MoistureQuestion 29 of 35Question 30 of 35 30. What type of transformer is this? Air core transformer Ferrite core transformer Ring core transformer Iron core transformerQuestion 30 of 35Question 31 of 35 31. Which transformer loss is determined by short circuit test? Windage loss Copper loss Hysteresis loss Eddy current lossQuestion 31 of 35Question 32 of 35 32. What is the advantage of stepped core in large transformers? Reduces hysteresis loss Reduces core space Reduces eddy current loss Minimizes copper useQuestion 32 of 35Question 33 of 35 33. What is the function of a conservator in a transformer? Releases internal pressure Transfers heat to atmosphere Allows oil expansion due to load variation Prevents moisture entryQuestion 33 of 35Question 34 of 35 34. Which type of transformer is used for high frequency applications? Ferrite core transformer Grain oriented core transformer Silicon steel core transformer Ring core transformerQuestion 34 of 35Question 35 of 35 35. What is the composition of silicon steel in transformer cores? 95% steel, 5% silicon 97% steel, 3% silicon 93% steel, 7% silicon 90% steel, 10% siliconQuestion 35 of 35 Loading...
