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






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






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






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






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






6. Anything above 600 volts is _____?






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






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






9. Divergence of the magnetic field causes this






10. The current related to turns ratio law






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






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






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






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






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






16. Function of the dielectric oil






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






18. Central magnetic core made of






19. 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






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






21. 3 types of transformers






22. A simple design has a core within each coil






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






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






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






26. Copper loss is known as _____ loss.






27. It refers to the direction of current flow in a closed circuit.






28. Current flows through the primary winding in response to primary voltage and sets up a magnetic field that varies in direction and stregnth. under the influence of the changing magnetic field an AC voltage/kv is induced across the secondary coil by e






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






30. What does transformer efficiency mean?






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






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






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






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






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






36. With no load on the secondary winding - a small current flows in the primary called _____ _____.






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






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






39. What is a rotation meter?






40. 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.






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






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






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






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






45. _____ currents are reduced by laminating the core.






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






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






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






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






50. 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