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






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






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






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






5. A ___________ transformer is a continuously adjustable Autotransformer.






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






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






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






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






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






11. 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.






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






13. 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






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






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






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






17. Used to increase the magnetic flux in a transformer






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






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






20. 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






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






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






23. The 4 types of transformer cores






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






25. The formula for the current related to voltage law






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






27. both coils in this core are heavily insulated






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






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






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






31. 3 types of transformers






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






33. 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.






34. 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.






35. A simple design has a core within each coil






36. 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)






37. What is a rotation meter?






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






39. The simplest type of transformer core






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






41. An instrument used to measure electrical current.






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






43. Copper loss is known as _____ loss.






44. 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.






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






46. _____ currents are reduced by laminating the core.






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






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






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






50. Central magnetic core made of