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 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.






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






3. The transformer winding to which the load is connected is called the _____ winding.






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






5. The 3 principle components of a transformer






6. This type of core is moderately efficient due to closing the core and layering design which reduces power loss from less leakage flux which provides a continuous path for magnetic flux and an increase in field strength






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






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






9. What does transformer efficiency mean?






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






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






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






13. 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






14. 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.






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






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






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






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






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






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






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






22. 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)






23. A ___________ transformer is a continuously adjustable Autotransformer.






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






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






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






27. Anything above 600 volts is _____?






28. The formula for the voltage related to turns ratio






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






30. _____ currents are reduced by laminating the core.






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






32. Transformer losses are classified as _____ and _____.






33. The 3 types of transformer power loss






34. 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






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






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






37. The output side it develops AC by electromagnetic mutual induction - Secondary voltage is induced in this coil






38. 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.






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






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






41. 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






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






43. What is a rotation meter?






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






45. Is concentrated in the metal core






46. 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






47. A single electrical circuit.






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






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






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