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






2. What does transformer efficiency mean?






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






4. closed core with a top and bottom. It directs the magnetic field towards the primary and secondary coils and increases the field stregnth






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






6. Is concentrated in the metal core






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






8. 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






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






10. 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.






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






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






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






14. 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.






15. The formula for the current related to voltage law






16. It refers to the direction of current flow in a closed circuit.






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






18. A simple design has a core within each coil






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






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






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






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






23. A choke coil uses this to induce current






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






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






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






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






28. Central magnetic core made of






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






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






31. 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






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






33. 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.






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






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






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






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






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






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






40. The 3 principle components of a transformer






41. An instrument used to measure electrical current.






42. The simplest type of transformer core






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






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






45. 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






46. The winding of a transformer to which electrical energy is supplied.






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






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






49. A single electrical circuit.






50. Copper loss is known as _____ loss.