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. An instrument used to measure electrical current.






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






3. 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.






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






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






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






7. The 4 types of transformer cores






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






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






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






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






13. How coercivity is minimized






14. Anything above 600 volts is _____?






15. What does transformer efficiency mean?






16. The shape of the core of the transformer ensures a ______________ for the magnetic flux with maximum concentration within the core and minimum leakage of the air






17. This type of core is moderately efficient due to closing the core and layering design which reduces power loss from less leakage flux which provides a continuous path for magnetic flux and an increase in field strength






18. A test instrument used to indicate low voltage potentials in the range of 110 to 600 volts either alternating or direct current. (slang term: wiggy)






19. Is concentrated in the metal core






20. The formula for the voltage related to turns ratio






21. The simplest type of transformer core






22. A choke coil uses this to induce current






23. A single electrical circuit.






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






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






26. A transformer which when supplied from a constant potential source automatically maintans a constant current in its secondary circuit under varying conditions of load impedance. Used on series street light circuits.






27. 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






28. 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.






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






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






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






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






33. The current related to turns ratio law






34. A simple design has a core within each coil






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






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






37. What is a rotation meter?






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






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






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






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






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






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






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






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






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






47. 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






48. 3 types of transformers






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






50. A ___________ transformer is a continuously adjustable Autotransformer.