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






2. Function of the dielectric oil






3. 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






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






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






6. 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






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






8. 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.






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






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






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






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






13. Used to increase the magnetic flux in a transformer






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






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






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






17. _____ currents are reduced by laminating the core.






18. 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






19. How coercivity is minimized






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






21. A single electrical circuit.






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






23. Anything above 600 volts is _____?






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






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






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






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






28. 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






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






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






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






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






33. A simple design has a core within each coil






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






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






36. A choke coil uses this to induce current






37. 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.






38. Transformer losses are classified as _____ and _____.






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






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






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






42. What is a rotation meter?






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






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






45. A transformer loses less than _% in energy






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






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






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






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






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