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. 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






2. The 3 principle components of a transformer






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






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






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






6. 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.






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






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






9. _____ currents are reduced by laminating the core.






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






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






12. The formula for the voltage related to turns ratio






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






14. Is concentrated in the metal core






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






16. The 3 types of transformer power loss






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






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






19. 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.






20. 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






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






22. Used to increase the magnetic flux in a transformer






23. 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






24. ___________ is often used in laminated cores - increases electrical resistance which decreases eddy currents






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






26. The formula for the current related to voltage law






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






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






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






30. What is a rotation meter?






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






32. 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.






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






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






35. Divergence of the magnetic field causes this






36. A choke coil uses this to induce current






37. The current related to turns ratio law






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






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






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






41. Transformer losses are classified as _____ and _____.






42. The terminals of the low voltage winding are marked _____.






43. A simple design has a core within each coil






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






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






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






47. 3 types of transformers






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






49. 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)






50. 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.