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






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






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






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






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






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






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






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






9. The 3 types of transformer power loss






10. Reference to a jumper or conductor - to or from a piece of electrical equipment.






11. Central magnetic core made of






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






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






15. The output rating of a transformer is based upon the maximum _____ the transformer is capable of carrying without exceeding a certain temperature rise.






16. A ___________ transformer is a continuously adjustable Autotransformer.






17. An instrument used to measure electrical current.






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






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






20. Refers to the transformer's ability to avoid power loss (heat)






21. For a step up and step down transformer if the turns ratio is constant this is the only way to change the output voltage






22. 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






23. Anything above 600 volts is _____?






24. Function of the dielectric oil






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






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






27. 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






28. The output which can be delivered for the time specified at rated secondary voltage and rated frequency without exceeding the specified temperature limitations.






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






30. The formula for the current related to voltage law






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






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






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






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






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






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






37. 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)






38. 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






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






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






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






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






43. A choke coil uses this to induce current






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






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






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






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






48. Waste of power known as transformer loss - often produced by closed-ended core






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






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