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






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






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






4. Anything above 600 volts is _____?






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






6. How coercivity is minimized






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






8. The formula for the current related to voltage law






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






10. What does transformer efficiency mean?






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






12. 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






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






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






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






16. _____ currents are reduced by laminating the core.






17. A choke coil uses this to induce current






18. Function of the dielectric oil






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






20. 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)






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






22. What is a rotation meter?






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






24. An instrument used to measure electrical current.






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






26. The current related to turns ratio law






27. 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






28. The formula for the voltage related to turns ratio






29. The 4 types of transformer cores






30. 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.






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






32. The 3 types of transformer power loss






33. Transformer losses are classified as _____ and _____.






34. When an alternating current is applied to the high-voltage (H) winding of a transformer with no load on the secondary (X) winding - a small current - called the _____ current - flows in the primary.






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






36. 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






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






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






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






40. Used to increase the magnetic flux in a transformer






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






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






43. 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






44. both coils in this core are heavily insulated






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






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






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






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






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






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