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






2. both coils in this core are heavily insulated






3. A stationary device for transferring alternating current electrical energy from one circuit to another circuit by electromagnetic means.






4. 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)






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






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






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






8. The 4 types of transformer cores






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






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






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






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






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






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






15. 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.






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






17. A part of a circuit made of a low melting point material so that it will melt and break the circuit when a specified current exceeded. Always the weakest point in the circuit.






18. 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






19. The 3 principle components of a transformer






20. 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 _____.






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






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






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






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






25. The current related to turns ratio law






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






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






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






29. 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






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






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






32. The simplest type of transformer core






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






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






35. Copper loss is known as _____ loss.






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






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






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






39. Function of the dielectric oil






40. The formula for the current related to voltage law






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






42. What is a rotation meter?






43. A transformer loses less than _% in energy






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






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






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






47. How coercivity is minimized






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






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






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