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






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






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






4. A magnetic field changing with respect to the conductor will generate a _____ in the conductor.






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






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






8. 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.






9. What does transformer efficiency mean?






10. A ___________ transformer is a continuously adjustable Autotransformer.






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






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






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






14. A transformer loses less than _% in energy






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






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






17. A choke coil uses this to induce current






18. A transformer is a device that has no moving parts and that transfers energy from one circuit to another by _____.






19. 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.






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






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






22. 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






23. Is concentrated in the metal core






24. 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.






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






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






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






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






29. 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 _____.






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






31. A designated limit of operating characteristics based on definite conditions.






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






33. The 3 principle components of a transformer






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






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






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






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






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






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






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






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






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






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






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






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






46. Copper loss is known as _____ loss.






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






48. 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






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






50. Anything above 600 volts is _____?