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






2. Used to increase the magnetic flux in a transformer






3. Kind of wire is the secondary coil in a transformer






4. The 3 principle components of a transformer






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






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






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






8. 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






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






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






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






12. both coils in this core are heavily insulated






13. Divergence of the magnetic field causes this






14. 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






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






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






17. A ___________ transformer is a continuously adjustable Autotransformer.






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






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






20. A choke coil uses this to induce current






21. 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






22. How coercivity is minimized






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






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






25. An instrument used to measure electrical current.






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






27. 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






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






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






30. A single electrical circuit.






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






32. The formula for the current related to voltage law






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






34. _____ currents are reduced by laminating the core.






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






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






37. Defined as the ratio of the power output to the power input (in a closed circuit containing resistance)






38. Copper loss is known as _____ loss.






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






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






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






42. 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.






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






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






45. What is a rotation meter?






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






47. 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.






48. Is concentrated in the metal core






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






50. 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