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. 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.






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






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






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






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






6. Central magnetic core made of






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






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






9. How coercivity is minimized






10. 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.






11. A ___________ transformer is a continuously adjustable Autotransformer.






12. _____ currents are reduced by laminating the core.






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






14. Function of the dielectric oil






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






16. Transformer losses are classified as _____ and _____.






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






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






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






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






21. The 4 types of transformer cores






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






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






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






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






26. 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)






27. The 3 principle components of a transformer






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






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






30. Divergence of the magnetic field causes this






31. 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.






32. Used to increase the magnetic flux in a transformer






33. The formula for the voltage related to turns ratio






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






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






36. 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.






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






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






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






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






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






42. A transformer rated at 500KVA and below used for voltage transformation on the distribuition system.






43. What is a rotation meter?






44. 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






45. The current related to turns ratio law






46. Copper loss is known as _____ loss.






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






48. The magnetic lines of force that flow from the north pole of a magnet and return to the south pole.






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






50. Autotransformers are not safe when they supply a _____ voltage from a high voltage source.