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 formula for the voltage related to turns ratio






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






3. An abnormal connection of relative low resistance - whether made accidentally or intentionally - between two point of different potential in a circuit.






4. Central magnetic core made of






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






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






7. 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






8. The 3 types of transformer power loss






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






10. The current related to turns ratio law






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






12. 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.






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






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






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






16. 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.






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






18. The formula for the current related to voltage law






19. A choke coil uses this to induce current






20. 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.






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






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






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






24. Function of the dielectric oil






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






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






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






28. A simple design has a core within each coil






29. What is a rotation meter?






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






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






32. 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






33. 3 types of transformers






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






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






36. 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






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






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






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






40. Used to increase the magnetic flux in a transformer






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






42. Is concentrated in the metal core






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






44. 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.






45. 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






46. What does transformer efficiency mean?






47. Copper loss is known as _____ loss.






48. Some losses occur in all transformers. These losses are classified as copper losses and _____ losses.






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






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