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. The current related to turns ratio law






2. _____ shows that the voltages across the windings of a transformer are directly proportional to the turns in each winding.






3. The formula for the voltage related to turns ratio






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






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






6. Instrument transformers reduce high voltages and currents to safe - usable values for the operation of _____ equipment.






7. Instrument transformers reduce high voltages and currents to safe - usable values for the operation of _____ _____.






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






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






10. An electromagnetic device that operates on the principle of self induction. It uses AC.






11. The formula for the current related to voltage law






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






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






14. The voltage induced in the coil is directly proportional to this






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






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






17. 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.






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






19. 3 types of transformers






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






21. The volt-amperes of the primary of a transformer is equal to the _____ - _____ output of the transformer.






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






23. If the transformer is used as a _____ transformer - the low voltage winding is the primary.






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






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






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






27. If the transformer is used as a _____ transformer - the high voltage winding is the primary.






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






29. The winding to which voltage is supplied is called the _____ winding.






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






31. Is concentrated in the metal core






32. A transformer loses less than _% in energy






33. Reference to a jumper or conductor - to or from a piece of electrical equipment.






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






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






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






37. The simplest type of transformer core






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






39. 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






40. A choke coil uses this to induce current






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






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






43. The energy is always transferred without a change in frequency - but usually with changes in _____ and _____.






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






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






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






47. _____ shows that the voltamperes of the primary of a transformer equal the voltamperes of the secondary of a transformer.






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






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






50. Divergence of the magnetic field causes this