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






2. Central magnetic core made of






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






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






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






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






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






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






9. Is concentrated in the metal core






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






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






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






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






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






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






16. A simple design has a core within each coil






17. What is a rotation meter?






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






19. A ___________ transformer is a continuously adjustable Autotransformer.






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






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






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






23. Copper loss is known as _____ loss.






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






25. Modern; used to control filament circuit; replaced both the rheostat and choke coil; operated on the electromagnetic principle that if an iron core within or near a coil is saturated with magnetic flux by an independed source of direct current - the






26. 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






27. 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.






28. The simplest type of transformer core






29. The 4 types of transformer cores






30. 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






31. The current related to turns ratio law






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






33. The 3 principle components of a transformer






34. 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






35. 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






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






37. Anything above 600 volts is _____?






38. Two coils wound on a closed iron core form a ________.






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






40. What does transformer efficiency mean?






41. The output side it develops AC by electromagnetic mutual induction - Secondary voltage is induced in this coil






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






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






44. An instrument used to measure electrical current.






45. 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 _____.






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






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






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






49. 3 types of transformers






50. 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.