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. Function of the dielectric oil






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






3. 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 _____.






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






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






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






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






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






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






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






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






12. The shape of the core of the transformer ensures a ______________ for the magnetic flux with maximum concentration within the core and minimum leakage of the air






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






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






15. 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.






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






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






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






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






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






21. 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






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






23. Copper loss is known as _____ loss.






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






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






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






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






28. 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.






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






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






31. 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.






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






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






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






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






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






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






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






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






40. both coils in this core are heavily insulated






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






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






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






44. A ___________ transformer is a continuously adjustable Autotransformer.






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






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






47. A single electrical circuit.






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






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






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