Test your basic knowledge |

Transformers

Subject : engineering
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Instrument transformers reduce high voltages and currents to safe - usable values for the operation of _____ equipment.






2. For a step up and step down transformer if the turns ratio is constant this is the only way to change the output voltage






3. The transformer winding to which voltage is supplied is called the _____ winding.






4. A ___________ transformer is a continuously adjustable Autotransformer.






5. The turns ratio between the windings (primary & secondary) of a transformer unless otherwise specified.






6. A variable transformer is a continuously adjustable _____ - has the primary winding and secondary winding electrically connected.






7. How coercivity is minimized






8. A magnetic field changing with respect to the conductor will generate a _____ in the conductor.






9. A transformer primary (H) that has 400 turns is wound to step the voltage down from 240 volts to 120 volts. The number or turns (TX) required in the secondary (X) winding is _____.






10. It refers to the direction of current flow in a closed circuit.






11. How coils serve as the primary and secondary windings for an autotransformer






12. The relationship between current and voltage in the coils are inverse






13. The total numbre of lines or force issuing from a pole. (north or south)






14. Copper loss is known as _____ loss.






15. With no load on the secondary winding - a small current flows in the primary called _____ _____.






16. Some losses occur in all transformers. These losses are classified as copper losses and _____ losses.






17. Determines if the transformer is a step up or step down transformer






18. The current related to turns ratio law






19. The terminals of the low voltage winding are marked _____.






20. The characteristic that requires energy to carry out the constant reorientation of the magnetic dipoles in the hysteresis loss






21. The 4 types of transformer cores






22. The turns of both windings are cut by the same flux; therefore the induced emf in each turn of both windings is the _____.






23. Two coils wound on a closed iron core form a ________.






24. Core losses are _____ loss and _____ - _____ loss.






25. The formula for the voltage related to turns ratio






26. Both the primary and secondary coils in a transformer are arranged around this






27. Kind of wire is the secondary coil in a transformer






28. The current flowing through the primary winding - in response to the applied primary voltage - sets this up






29. Connected to earth or to some conducting body which serves in place of the earth.






30. Is concentrated in the metal core






31. 3 types of transformers






32. The capacity of a transformer is rated in ____ _____.






33. Current flows through the primary winding in response to primary voltage and sets up a magnetic field that varies in direction and stregnth. under the influence of the changing magnetic field an AC voltage/kv is induced across the secondary coil by e






34. Divergence of the magnetic field causes this






35. The output rating of a transformer is based upon the maximum _____ the transformer is capable of carrying without exceeding a certain temperature rise.






36. How a variable degree of core saturation is accomplished in a saturable reactor?






37. Anything above 600 volts is _____?






38. The transformer winding to which the load is connected is called the _____ winding.






39. Defined as the ratio of the power output to the power input (in a closed circuit containing resistance)






40. An instrument used to measure electrical current.






41. Provides the ratio between the applied primary voltage and the induced secondary voltage as result of the turns ratio






42. both coils in this core are heavily insulated






43. A transformer is a device that either increases or decreases alternating current and voltage using this principle






44. A transformer loses less than _% in energy






45. ___________ is often used in laminated cores - increases electrical resistance which decreases eddy currents






46. A system of conductors in which at least one conductors or point (usually the middle wire or neutral point of a transformer or generator windings) is intentionally grounded either solididly or through a current-limiting device.






47. has a laminated iron core (layers of metal plates)






48. A partial or total local failure in the insulation or continuity of a conductor.






49. What does transformer efficiency mean?






50. A magnet made by winding a coil of wire around a soft iron core. Current passed through this winding produces magnetic lines of force in the coil.






Can you answer 50 questions in 15 minutes?



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