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






2. 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.






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






4. The simplest type of transformer core






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






6. An instrument used to measure electrical current.






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






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






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






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






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






12. 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






13. The 4 types of transformer cores






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






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






16. The 3 types of transformer power loss






17. A ___________ transformer is a continuously adjustable Autotransformer.






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






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






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. 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)






22. 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.






23. 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






24. A simple design has a core within each coil






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






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






27. Anything above 600 volts is _____?






28. The current related to turns ratio law






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






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






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






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






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






34. The winding of a transformer to which electrical energy is supplied.






35. 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






36. What does transformer efficiency mean?






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






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






39. _____ currents are reduced by laminating the core.






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






41. closed core with a top and bottom. It directs the magnetic field towards the primary and secondary coils and increases the field stregnth






42. The formula for the voltage related to turns ratio






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






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






45. Transformers with 4800 volt primaries and 120/240 volt secondaries - either pole or subway type - with two secondary windings terminating at internal links which provide for parallel operation of the secondary windings at 120 volts or series operatio






46. The volt-amperes of the primary of a transformer is equal to the _____ - _____ output of the transformer.






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






48. Central magnetic core made of






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






50. The 3 principle components of a transformer