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 designated limit of operating characteristics based on definite conditions.






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






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






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






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






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






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






8. 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)






9. A transformer loses less than _% in energy






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






11. The turns of both windings are cut by the same flux; therefore the induced emf in each turn of both windings is the _____.






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






13. 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






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






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






16. A part of a circuit made of a low melting point material so that it will melt and break the circuit when a specified current exceeded. Always the weakest point in the circuit.






17. A choke coil uses this to induce current






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






19. The output rating of a transformer is based upon the maximum _____ the transformer is capable of carrying without exceeding a certain temperature rise.






20. How coercivity is minimized






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






22. A ___________ transformer is a continuously adjustable Autotransformer.






23. A simple design has a core within each coil






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






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






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






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






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






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






30. What does transformer efficiency mean?






31. Transformers with 4800 volt primaries and 120/240 volt secondaries - either pole or subway type - with two secondary windings terminating at internal links which provide for parallel operation of the secondary windings at 120 volts or series operatio






32. Copper loss is known as _____ loss.






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






35. The current related to turns ratio law






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






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






38. 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 _____.






39. 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






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






41. What is a rotation meter?






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






43. The simplest type of transformer core






44. Is concentrated in the metal core






45. Used to increase the magnetic flux in a transformer






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






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






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






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






50. 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.