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






2. 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.






3. 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)






4. Hysteresis Loss can be reduced by using a core with this feature






5. 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 _____.






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






7. 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.






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






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






10. To prevent injury to personnel when servicing any equipment connected to a current transformer - the secondary winding must be ____ - _____.






11. _____ currents are reduced by laminating the core.






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






13. Divergence of the magnetic field causes this






14. The total numbre of lines or force issuing from a pole. (north or south)






15. The 3 types of transformer power loss






16. Anything above 600 volts is _____?






17. The simplest type of transformer core






18. The 3 principle components of a transformer






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






20. How coercivity is minimized






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






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






23. The current related to turns ratio law






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






25. A single electrical circuit.






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






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






28. Transformer losses are classified as _____ and _____.






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






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






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






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






33. Function of the dielectric oil






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






35. 3 types of transformers






36. The formula for the voltage related to turns ratio






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






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






39. Is concentrated in the metal core






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






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






42. An instrument used to measure electrical current.






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






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






45. A simple design has a core within each coil






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






47. Used to increase the magnetic flux in a transformer






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






49. Copper loss is known as _____ loss.






50. The 4 types of transformer cores