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 transformer rated at 500KVA and below used for voltage transformation on the distribuition system.






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






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






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






5. The winding to which the load is connected is called the _____ winding.






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






7. The output which can be delivered for the time specified at rated secondary voltage and rated frequency without exceeding the specified temperature limitations.






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






9. A transformer loses less than _% in energy






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






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






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






13. Is concentrated in the metal core






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






15. The 3 types of transformer power loss






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






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






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






19. What does transformer efficiency mean?






20. A part of a circuit made of a low melting point material so that it will melt and break the circuit when a specified current exceeded. Always the weakest point in the circuit.






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






22. 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.






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






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






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






26. What is a rotation meter?






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






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






29. A ___________ transformer is a continuously adjustable Autotransformer.






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






31. Transformer losses are classified as _____ and _____.






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






33. The formula for the current related to voltage law






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






35. The terminals of the high voltage winding are marked _____.






36. 3 types of transformers






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






38. both coils in this core are heavily insulated






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






40. Hysteresis Loss can be reduced by using a core with this feature






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






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






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






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






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






46. A single electrical circuit.






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






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






49. Function of the dielectric oil






50. Used to increase the magnetic flux in a transformer