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






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






3. Copper loss is known as _____ loss.






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






5. Anything above 600 volts is _____?






6. The output which can be delivered for the time specified at rated secondary voltage and rated frequency without exceeding the specified temperature limitations.






7. The 4 types of transformer cores






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






9. What does transformer efficiency mean?






10. both coils in this core are heavily insulated






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






12. 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.






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






14. A transformer is a device that either increases or decreases alternating current and voltage using this principle






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






16. 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.






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






18. 3 types of transformers






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






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






21. A simple design has a core within each coil






22. The current flowing through the primary winding - in response to the applied primary voltage - sets this up






23. Is concentrated in the metal core






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






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






26. How coercivity is minimized






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






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






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






30. 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.






31. Function of the dielectric oil






32. 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)






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






34. 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.






35. Transformer losses are classified as _____ and _____.






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






37. 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 _____.






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






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






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






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






42. _____ currents are reduced by laminating the core.






43. Central magnetic core made of






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






45. 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






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






47. The 3 principle components of a transformer






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






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






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