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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. Copper loss is known as _____ loss.






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






3. How coercivity is minimized






4. Divergence of the magnetic field causes this






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






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






7. The formula for the voltage related to turns ratio






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






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






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






11. 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)






12. 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.






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






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






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






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






17. 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






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






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






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






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






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






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






24. _____ currents are reduced by laminating the core.






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






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






27. both coils in this core are heavily insulated






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






29. A ___________ transformer is a continuously adjustable Autotransformer.






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






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






32. What is a rotation meter?






33. 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.






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






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






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






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






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






39. 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






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






41. An instrument used to measure electrical current.






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






43. 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.






44. 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.






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






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






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






48. 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






49. The formula for the current related to voltage law






50. Modern; used to control filament circuit; replaced both the rheostat and choke coil; operated on the electromagnetic principle that if an iron core within or near a coil is saturated with magnetic flux by an independed source of direct current - the







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