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






2. The 3 principle components of a transformer






3. An abnormal connection of relative low resistance - whether made accidentally or intentionally - between two point of different potential in a circuit.






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






5. 3 types of transformers






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






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






8. A large amount of power wasted with the open-ended core






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






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






11. Modern; extremely efficient-more effective coupling between primary and secondary coils; smaller and lighter






12. Copper loss is known as _____ loss.






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






14. The current related to turns ratio law






15. A transformer is a device that has no moving parts and that transfers energy from one circuit to another by _____.






16. This core is more efficient than the air core because the iron core in each coil intensifies the magnetic flux in both primary and secondary coils when they become magnetized as current flows through each set of coils






17. This is the most advanced and most efficient type of tansformer; it is commonly used in x-ray equipment






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






19. How the voltage and the number of turns are related for the voltage related to turn ratio






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






21. Insulated primary and secondary coils are in close proximity to each other - no iron core and very innefficient






22. Autotransformers are not safe when they supply a _____ voltage from a high voltage source.






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






24. Central magnetic core made of






25. In a transformer the _____ current will always flow in such a direction that its magnetizing action will oppose the magnetizing action of the primary winding.






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






27. Refers to the transformer's ability to avoid power loss (heat)






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






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






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






31. What is a rotation meter?






32. Transformers with 4800 volt primaries and 120/240 volt secondaries - either pole or subway type - with two secondary windings terminating at internal links which provide for parallel operation of the secondary windings at 120 volts or series operatio






33. A designated limit of operating characteristics based on definite conditions.






34. The formula for the current related to voltage law






35. The entire transformer is placed in a metal tank then immersed in ________.






36. 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






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






38. Transformers designed for 4800 volt primary operation - but the secondaries are connected 240/480 volts. Winding ratio is 10:1






39. The magnetic lines of force that flow from the north pole of a magnet and return to the south pole.






40. The formula for the voltage related to turns ratio






41. The input side that attaches to the AC supply it recieves the electrical energy or incoming voltage






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






43. 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.






44. What does transformer efficiency mean?






45. A ___________ transformer is a continuously adjustable Autotransformer.






46. 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 _____.






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






48. A transformer loses less than _% in energy






49. To minimize ________ in transformer construction - the primary and secondary windings are placed on the same leg(s) of the core.






50. To prevent injury to personnel when servicing any equipment connected to a current transformer - the secondary winding must be ____ - _____.