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






2. 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 _____.






3. Copper loss is known as _____ loss.






4. When an alternating current is applied to the high-voltage (H) winding of a transformer with no load on the secondary (X) winding - a small current - called the _____ current - flows in the primary.






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






6. Divergence of the magnetic field causes this






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






8. The number of turns can be adjusted in these types of transformers






9. The formula for the current related to voltage law






10. A transformer loses less than _% in energy






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






12. What does transformer efficiency mean?






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






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






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






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






17. A ___________ transformer is a continuously adjustable Autotransformer.






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






19. 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.






20. The relationship between amperage flowing through the coils and the number of turns on individual coils is inverse






21. 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






22. A stationary device for transferring alternating current electrical energy from one circuit to another circuit by electromagnetic means.






23. Is concentrated in the metal core






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






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






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






27. Waste of power known as transformer loss - often produced by closed-ended core






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






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






30. 3 types of transformers






31. This type of transformer power loss is caused by the continually changing AC current movement which constantly magnetizes/demagnetizes/re-magnetizes






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






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






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






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






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






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






38. _____ currents are reduced by laminating the core.






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






40. 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






41. The 3 principle components of a transformer






42. 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.






43. Anything above 600 volts is _____?






44. The simplest type of transformer core






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






46. What is a rotation meter?






47. The loss of power required to reverse the core magnatism each time the current reverses. This loss is caused by friction between the molecules of iron as these particles are aligned first in one direction and the in the opposite direct as current dir






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






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






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